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Executive Summary


Strategic Advice on Managed Aquifer Recharge using Treated Wastewater on the Swan Coastal Plain

Section 16(e) report and recommendations of the Environmental Protection Authority

Environmental Protection Authority Perth, Western Australia Bulletin 1199 October 2005

ISBN. 0 7307 6839 2 ISSN. 1030 - 0120

Executive Summary
Introduction The Environmental Protection Authority (EPA) has been requested by the Minister for the Environment to provide advice under section 16(e) of the Environmental Protection Act 1986 on managed aquifer recharge (MAR) using treated wastewater on the Swan Coastal Plain. The EPA released a Discussion Paper on this topic for 12 weeks public comment on 4 April 2005 and held six forums around the Perth metropolitan area. This allowed the EPA to obtain feedback on the issues raised in the Discussion Paper, and to consider public and government agency comments in the formulation of its advice. The EPA subsequently released draft section 16(e) advice in July 2005 for a 4 week public comment period. Following consideration of the contributions arising from this consultation process, this report provides the final section 16(e) advice requested by the Minister. Advice MAR is the infiltration or injection of water into an aquifer. This advice considers only MAR using treated wastewater for the Swan Coastal Plain. The EPA notes that MAR is increasingly being used as a means of water management both within Australia, and around the world. The EPA supports in principle the concept of wastewater reuse, and recognises the potential for MAR using treated wastewater to play an important role in the sustainable management of Western Australia’s water resources. This is particularly the case given the reduction in rainfall which has occurred in the south west of the State since the mid 1970s, and the large reliance on groundwater resources. There are a number of potential environmental, health and social issues associated with MAR, and these will need to be addressed prior to the implementation of any significant MAR scheme. The use of MAR has the potential to provide benefits for water resources and environmental management. These include maintenance of wetlands and caves, reduced salt water intrusion, increased water availability for irrigation use, and augmentation of drinking water supplies. The EPA recognises that it will not be possible to implement MAR using treated wastewater without some degree of risk. These risks should be assessed against the potential environmental and sustainability benefits of MAR schemes, and the risks associated with taking no action. The EPA expects that in a number of situations, the risks associated with MAR can be managed to negligible or low levels to provide, on balance, a number of benefits for water resources and environmental management. The EPA supports further investigation of MAR on the Swan Coastal Plain, while advocating a precautionary approach to ensure that the environment and public health are protected. A staged approach is recommended, starting with trials and projects of low risk. Given the lack of experience with MAR on the Swan Coastal Plain to date, and the site-specific nature of transport and attenuation of contaminants, the EPA

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expects that trials will be necessary prior to the implementation of any large scale MAR scheme. Proponents of MAR schemes will be required to undertake a systematic risk assessment of their proposal. Any MAR proposal that is likely, if implemented, to have a significant effect on the environment must be referred to the EPA under section 38 of the Environmental Protection Act 1986. The EPA expects that any large scale MAR using treated wastewater, or any trials or MAR proposals in areas of high environmental value, are likely to require risk assessment and environmental impact assessment. In line with Department of Environment and Department of Health advice, the EPA considers that trials should be conducted outside of Public Drinking Water Source Areas before any large scale proposal for use of MAR to augment drinking water supplies is developed. MAR proposals require Department of Health approval under the Health Act 1911. Recommendations The EPA submits the following recommendations to the Minister for the Environment:
? ? ?

that the Minister notes that this advice addresses managed aquifer recharge (MAR) using treated wastewater on the Swan Coastal Plain; that the Minister considers the report on the relevant factors as set out in Section 4; that the Minister notes that the EPA supports in principle the concept of wastewater use and supports the investigation of MAR using treated wastewater as a means of water management on the Swan Coastal Plain. The EPA has provided a strategic framework in which the concept of MAR on the Swan Coastal Plain can be considered further.

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Contents
Page Executive Summary ......................................................................................................i 1. 2. Introduction..........................................................................................................1 Background ..........................................................................................................1 2.1 2.2 2.3 2.4 3. Managed Aquifer Recharge .......................................................................1 Water Recycling and Wastewater Treatment ............................................2 Risk Assessment Framework.....................................................................6 Consultation ...............................................................................................7

Context ..................................................................................................................7 3.1 3.2 3.3 3.4 International Context .................................................................................7 National Context ......................................................................................10 State Context............................................................................................12 Principles of the Environmental Protection Act 1986 .............................14

4.

Factors.................................................................................................................15 4.1 4.2 4.3 4.4 4.5 4.6 Sustainability............................................................................................15 Environment.............................................................................................17 Public Health............................................................................................21 Regulatory Requirements and Guidelines ...............................................23 Aboriginal Heritage .................................................................................25 Community Involvement .........................................................................26

5.

EPA Advice.........................................................................................................26 5.1 5.2 Overarching advice ..................................................................................26 Potential Applications on the Swan Coastal Plain...................................28

6. 7. 8.

Other advice .......................................................................................................36 Future Work.......................................................................................................37 Conclusions.........................................................................................................38

Tables 1. Summary of recycled water class quality and uses 2. Summary of key issues and requirements related to potential MAR applications Figures 1. MAR by infiltration, (b) MAR by injection with well abstraction 2. A common wastewater treatment process used to obtain secondary treated wastewater in Perth (Tertiary treatment can involve many different processes and is not represented in detail here) 3. Major wastewater treatment plants in the Perth region (Water Corporation) 4. Depletion of the Gnangara Mound since 1979 (Vogwill 2004) Appendices 1. References 2. Draft Department of Health ‘Recycled Water – Groundwater Recharge Guidelines’ 3. Summary of MAR forum outcomes 4. List of Submitters (Discussion Paper) 5. Summary of Submissions and Response (Discussion Paper) 6. List of Submitters (Draft section 16(e)) 7. Summary of Submissions and Response (Draft section 16(e))

1.

Introduction

The Environmental Protection Authority (EPA) has been requested by the Minister for the Environment to provide advice under section 16(e) of the Environmental Protection Act 1986 regarding managed aquifer recharge (MAR) using treated wastewater on the Swan Coastal Plain. The Minister requested that this advice provide the guiding principles and advice of the EPA in order to provide a strategic framework within which the concept of MAR on the Swan Coastal Plain can be considered further. As a first stage in providing this advice, the EPA released a Discussion Paper in April 2005 (Environmental Protection Authority 2005) for 12 weeks public comment. This is available from www.epa.wa.gov.au. The EPA also held six public forums around the Perth metropolitan area in May 2005 to provide an opportunity for members of the public to learn about and raise issues related to MAR. The key issues raised in the public consultation phase are discussed in Section 2.4, and further details of the submissions and forum outcomes are provided in Appendices 3 and 5. Following consideration of the issues raised, the EPA released draft section 16(e) advice in July 2005 for a 4 week public comment period. The issues raised in relation to the draft are provided with the EPA’s responses in Appendix 7. This report provides the final advice of the EPA to Government and to future proponents of MAR schemes using treated wastewater on the Swan Coastal Plain. It identifies what the EPA views as the key risks and opportunities associated with MAR, and key knowledge gaps which require further research. This advice also identifies issues that should be addressed in order for the EPA to determine the acceptability of any MAR proposal. The latter part of this report considers a number of potential applications of MAR identified by the Water Corporation, and provides the initial considerations of the Authority regarding these.

2.
2.1

Background
Managed Aquifer Recharge

Aquifers are below ground layers of earth or porous rock that are saturated with groundwater. These are an important source of drinking water in Perth, with approximately half of Perth’s drinking water sourced from aquifers (Allison et al. 2002). They are also used to provide large quantities of water for horticulture, industrial uses and irrigation of recreation areas and gardens. Additionally, many natural features, such as wetlands, are either directly or indirectly reliant on groundwater. MAR, also known as artificial recharge, is the infiltration (Figure 1a) or injection (Figure 1b) of water into an aquifer. Infiltration methods include recharge basins, surface spreading, irrigation pits, and trenches. Injection is carried out using a bore (injection well) or series of bores, generally for deeper or confined aquifers. The term MAR encompasses both aquifer recharge without abstraction, and recharge for later abstraction (Figure 1b). Abstraction is the withdrawal of groundwater.

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MAR has been used for centuries throughout the world, particularly in arid and desert areas where natural recharge is intermittent (Pyne 1995). MAR may be used as a means of storing water underground in times of surplus to meet need in times of demand. The water recovered may be used for purposes including the prevention of salt water intrusion in coastal areas, horticultural irrigation, environmental benefits, or to increase drinking water supplies. MAR is described in detail in Management of Aquifer Recharge for Sustainability (Dillon 2000).

a

b Figure 1: (a) MAR by infiltration, (b) MAR by injection with well abstraction

2.2

Water Recycling and Wastewater Treatment

Drinking water is scheme water that is supplied to residential areas and is suitable for drinking and domestic uses, such as cooking, showers, baths and garden reticulation. Wastewater (or sewage) is the spent or used water from a community. It comes from domestic, commercial and industrial sources, and includes toilet water. Treated wastewater is wastewater that has undergone treatment in a wastewater treatment plant, as shown schematically in Figure 2. Wastewater treatment may comprise up to three stages, described below. The major wastewater treatment plants in the Perth area are shown in Figure 3. More details of wastewater treatment processes can be found in Wastewater Engineering: Treatment, Disposal and Reuse (Tchobanoglous and Burton 1991).

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AR PRIM

NT TME REA YT

SE

CO ND A

Primary Settling Aeration Tank

RY T

RE A

TM EN T

Grit Chamber
Grit

Waste Sludge

Returned Sludge

Final Settling Screen Racks
Screenings Treated Wastewater

TERTIARY TREATMENT

Figure 2: A common wastewater treatment process used to obtain secondary treated wastewater in Perth. (Tertiary treatment can involve many different processes and is not represented in detail here) Primary treatment is the initial stage of wastewater treatment and involves removing solid particles from the wastewater. Heavy particles sink to the bottom and are removed. Secondary treatment follows primary treatment. The wastewater flows into tanks where bacteria are used to treat it, often with addition of oxygen. The wastewater then flows into settling tanks where more particles settle to the bottom for removal and any floating scum is also removed. This treatment helps to remove dissolved and suspended organic and inorganic solids. Tertiary treatment further removes inorganic compounds, and substances such as compounds of nitrogen and phosphorus. Tertiary treatment can involve a range of different processes depending on the required end water quality. It commonly involves filtration, either through a medium such as sand, or through a membrane (or multiple membranes for very high water quality) and may include disinfection with chlorine, ozone or ultra-violet radiation. Recycled (or reclaimed) water is water which, as a result of treatment of waste, is suitable for direct beneficial use or a controlled use that would not otherwise occur. In Australia, recycled water is classified by water quality parameters and subsequent safe uses, however there is some variation in definitions between the states. As used in this paper, the five classes of recycled water are: Class A+ Class A+ water is made by the process used to produce Class A water, with the addition of an advanced treatment stage. Advanced treatment processes include chemical clarification, carbon adsorption, reverse osmosis and other membrane processes, air stripping, ultrafiltration, and ion exchange. There is the potential for this class of water to be used to provide drinking water by MAR.

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Two Rocks WWTP Yanchep WWTP Proposed Alkimos WWTP Bullsbrook WWTP Bullsbrook

BEENYUP OUTFALL 34 GL/yr

Beenyup WWTP Mundaring WWTP Mundaring Subiaco WWTP

SUBIACO OUTFALL 20 GL/yr

Woodman Pt WWTP Kwinana WWTP

Point Peron WWTP

CAPE PERON OUTFALL 44 GL/yr

Proposed East Rockingham WWTP

Gordon Rd WWTP Halls Head WWTP Caddadup WWTP Pinjarra WWTP

Figure 3: Major wastewater treatment plants in the Perth region. Corporation)

(Water

Class A Class A water is produced by tertiary treatment process with pathogen removal. Both Class A and A+ water require disinfection (the destruction, inactivation or removal of pathogenic micro-organisms). Class A water may be used for: ? urban non-drinking water use with uncontrolled public access; ? agricultural production, e.g. food crops which are consumed raw; and ? industrial applications with the potential for worker exposure. The Kwinana Water Reclamation Plant produces Class A recycled water using wastewater from the Woodman Point Wastewater Treatment Plant. This is used for industrial purposes such as process and cooling water in the Kwinana Industrial Area.

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Class B Class B water is produced by secondary treatment with some pathogen reduction. This water may be used for: ? agricultural application such as cattle grazing; and ? industrial applications such as washdown water. Class C Class C water is produced by secondary treatment with minor pathogen removal. With strict management processes Class C water can be used for: ? urban non-drinking water applications with controlled access; ? food crop production where produce is cooked or washed; and ? industrial systems with no potential for worker exposure. Class C water is used in Western Australia to irrigate bluegum (Eucalyptus globulus) plantations in places such as Manjimup, Margaret River, Nannup and Albany. With strict management processes Class C water is also used to irrigate ovals and golf courses in places such as Broome, Manjimup, Karratha and Northam. Class D Class D water is produced by a secondary treatment process. Class D water may be used for: ? non-food crops such as woodlots, turf growing and flowers. Class D water is infiltrated to shallow aquifers in Halls Head and Geraldton, and extracted downstream as a higher quality product for use in irrigation. The California Code of Regulations Title 22 is also referred to in this document, and is used as the basis for wastewater quality requirements in other States of Australia. This sets bacteriological water quality standards on the basis of the expected degree of public contact with the recycled water. For applications with a high potential for the public to come in contact with the recycled water, Title 22 requires disinfected tertiary treatment. For applications with a lower potential for public contact, Title 22 requires three levels of secondary treatment, basically differing by the amount of disinfection required. In addition to establishing recycled water quality standards, Title 22 specifies the reliability and redundancy for each recycled water treatment and use operation. The EPA notes that the Department of Health is the responsible agency for approving the health aspects of water recycling schemes in Western Australia. Water quality requirements, such as turbidity, chlorine residual and bacterial requirements, for each class of water are provided in the Department of Health Draft Guidelines (Appendix 2). The classes are summarised in Table 1.

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Table 1. Summary of recycled water class quality and uses Class Pathogen target Uses Class A+ 1 7 log reductions2 Drinking water by MAR Class A 7 log reductions Unrestricted urban non-drinking water use. Food crops for raw human consumption. Third pipe systems. Class B <100 E. coli Agricultural, e.g. dairy grazing. Industrial systems with potential worker exposure Class C <1000 E. coli Controlled access urban use. Food crops for cooked or processed human consumption. Industrial systems with no potential worker exposure. Class D <10 000 E. coli Agricultural non-food crops, such as turf, woodlots and flowers
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Class A+ water must also meet the Department of Health chemical guidelines for recycled water (currently under development). 2 A measure of effectiveness of a process to remove certain viruses or bacteria. Each log reduction reduces the number of infectious units (e.g. viruses or bacteria) by a factor of 10. For example, one log reduction reduces the original level by 90%, two log reductions reduces the original level by 99%, three by 99.9%, etc. The log reduction targets are based on recycled blackwater, the worst case scenario, and would be less for greywater or stormwater systems.

2.3

Risk Assessment Framework

Exposure to risk is recognised as a normal aspect of everyday life. People accept a certain level of risk as necessary to achieve certain benefits. For example, driving a car is a risk which most people take daily. It is generally not practical to seek zero risk; instead risks must be balanced against potential benefits. In evaluating the concept of MAR, risk benefit analysis provides a tool for the comparison of the risks to its related benefits. Risk is defined as a combination of the probability, or frequency, of occurrence of a defined hazard and the magnitude of the consequences of the occurrence (Warner 1992). A hazard is the potential for adverse consequences of some primary event, sequence of events or combination of circumstances (Warner 1992). Principle 1 of the Environmental Protection Act 1986 (The precautionary principle) requires assessment of the risk-weighted consequences of options in decision-making. Around the world there are a large number of standards and guidelines for the use of recycled water. These reflect the difference in attitudes to risk management, in addition to resource availability (Anderson et al. 2001). In Australia, National Guidelines on Water Recycling are being developed by the Joint Steering Committee for Environmental Protection and Heritage Council and National Resource Management Ministerial Council. A critical part of this is the development of an environmental risk assessment process for the use of treated wastewater. With regard to public health, the Australian Drinking Water Guidelines (National Health and Medical Research Council and Natural Resources Management Ministerial Council 2004) provides guidance on the monitoring and management of drinking water systems, and information on potential contaminants. The guidelines recommend a multi-barrier risk based framework for the protection of drinking water

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quality. Potential hazards to the water supply are identified and assessed in terms of the level of risk each poses. The World Health Organization (Aertgeerts and Andelakis 2003) also use a risk management framework for the consideration of MAR.

2.4

Consultation

As described earlier, in order to invite comment on MAR using treated wastewater on the Swan Coastal Plain and to provide an opportunity for members of the public and government agencies to raise issues relating to MAR, the EPA released a Discussion Paper and held six public forums. The Discussion Paper was released on 4 April 2005 for 12 weeks public comment. This is available from www.epa.wa.gov.au. Forums were held in Mosman Park, Hillarys, Riverton, Wanneroo, Bibra Lake and Midland during May 2005. Attendees came from three categories: those self-selected in response to newspaper advertisements, by invitation as a member of an interest group, and those invited following random selection from the electoral roll. At the forums, representatives from the key Government agencies, the Department of Environment; Water Corporation; and Department of Health, presented the key issues associated with MAR, and its potential applications on the Swan Coastal Plain. The PowerPoint slides shown at the forums are available from www.epa.wa.gov.au. The key issues identified in submissions to the EPA and the key outcomes from each forum are provided in Appendix 3. A list of submitters is also provided in Appendix 4, and Appendix 5 provides the response of the EPA to the submissions. The forum attendees were generally aware of the current water issues facing Perth, and supportive of the concept of wastewater recycling. There was generally a high level of support for MAR using treated wastewater on the Swan Coastal Plain, particularly for non-drinking water applications. The potential for drinking water reuse raised the greatest number of concerns, however the majority of attendees, supported the concept of MAR using treated wastewater to provide drinking water. Members of the public were of the view that it is the responsibility of the Departments of Health and Environment to set and enforce appropriate health and environmental standards respectively. Following consideration of the issues arising from the Discussion Paper, the EPA released draft section 16(e) advice in July 2005 for a 4 week public comment period. A list of submitters is also provided in Appendix 7, and Appendix 7 provides a summary of the issues raised in relation to the draft, along with the EPA’s responses.

3.
3.1

Context
International Context

Around the world, demand for freshwater is increasing rapidly. An investigation by the World Resources Institute found that while many regions of the world have ample freshwater supplies, four in 10 people currently live in regions experiencing water scarcity (Revenga et al. 2000). By 2025, at least 3.5 billion people, nearly half of the world’s population, will face water scarcity. Water shortages are a result of factors 7

including increasing population, unsustainable water abstraction, contamination of water sources, and changing climatic and precipitation patterns. The EPA notes that a number of international guidelines related to MAR exist, including the World Health Organization (Aertgeerts and Angelakis 2003), and the International Source Book On Environmentally Sound Technologies for Wastewater and Stormwater Management (United Nations Environment Programme 2000). In many areas of the world, inadvertent water recycling occurs through the discharge of wastewater into rivers and lakes, with subsequent use downstream. This occurs in Europe and North America in areas where populations live along inland river systems (Prime Minister’s Science, Engineering and Innovation Council 2003). For example, along the Thames, the Rhine and the Ohio Rivers, wastewater from upstream cities is treated and returned to the river. The mix of river water and treated wastewater is retreated and used to provide drinking water downstream. Planned wastewater reuse, both direct and indirect, is also common around the world. Uses include: ? horticulture; ? industry; ? environmental benefits; and ? drinking water. Direct reuse of wastewater is considered to provide context, however this section 16(e) advice does not consider the direct reuse of wastewater. Direct reuse is the direct transfer of wastewater to the user, without intermediate storage in the environment. Horticulture In many cities, wastewater is discharged directly to land or water without any treatment. For example, untreated wastewater from the Mexico City basin has been used for decades to irrigate cropland in the Mezquital Valley, State of Hidalgo, Mexico (Pescod 1992). This may present a health risk in cases where there is direct human contact with the wastewater. In Monterey Bay, California, tertiary treated wastewater is used by vegetable growers for crop irrigation. This project was initiated in the 1980’s due to seawater intrusion in the Salinas Valley impacting on the quality of groundwater. Currently 24 GL1 per year of recycled water meeting the Title 22 California Code of Regulations is supplied to approximately 4900 ha of farmland in the northern Salinas Valley for agricultural and irrigation uses (Pescod 1992). In Israel, MAR is used in combination with direct wastewater reuse to provide irrigation water. Between 65 and 70% of urban and industrial wastewater is reused in agriculture following secondary treatment (Icekson-Tal et al. 2003). The Dan Region Reclamation Plant is the largest wastewater treatment and reuse project in Israel, producing over 130 GL of recycled water per year. It has been in operation for 25 years. Wastewater from the Dan Region is conveyed to four recharge basins covering

1 gigalitre = 109 L = 1000 000 000 L. One gigalitre is the approximate volume of 450 Olympic swimming pools.

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an area of 80 ha, with infiltration by alternate flooding and drying (Icekson-Tal et al. 2003). Abstraction wells are located 300 to 1500 m from the recharge basins. Industry Direct reuse of wastewater for industrial purposes is common around the world and generally well-supported by communities due to the low level of human contact with the recycled water. Industrial reuse schemes exists in many countries, for example in Singapore treated wastewater produced by the NEWater plant (tertiary treated with microfiltration, reverse osmosis, and disinfection) is used in wafer fabrication plants (http://www.pub.gov.sg/NEWater). MAR is uncommon for the supply of recycled water to industry. Heavy industries generally use water at a relatively constant rate year round, and therefore can be supplied directly with recycled water, which is also produced at a relatively constant rate throughout the year. Environmental benefits A number of examples of MAR projects for environmental benefits exist around the world, often overlapping with horticultural and drinking water use. For example, Water Factory 21 in Orange County, California prevents sea water intrusion by injecting treated wastewater into the aquifer. This project has been in operation since 1976. It has provided significant data on the capability and reliability of advanced wastewater treatment processes to remove microbiological and chemical constituents, and data on groundwater quality and monitoring techniques. In the West Basin Municipal Water District, California, secondary treated wastewater is injected into the coastal South Bay aquifers, following microfiltration and reverse osmosis, to prevent salt water from entering the aquifer (Australian Academy of Technological Sciences and Engineering 2004). Initially a combination of 50% imported water and 50% of recycled water were injected. In 2000 an expert review panel and the California Department of Health Services gave approval for 100% recycled water to be injected. Drinking water Direct reuse of treated wastewater for drinking is relatively uncommon. In Windhoek, Namibia, treated wastewater from the Gammams wastewater treatment plant supplies half of the water into the Windhoek drinking water network, with the other half obtained from a surface reservoir. The capacity of the plant is currently being upgraded to 7.67 GL per year. Since 1968, recycled water has contributed 4% of the total water supply in Windhoek, though this has reached up to 31% during droughts (Anderson 2003). In Singapore the NEWater demonstration water recycling plant was commissioned to produce treated wastewater for drinking. Wastewater is tertiary treated with advanced dual-membrane (microfiltration and reverse osmosis) and ultraviolet technologies. A review by an expert panel concluded in 2002 that the plant has demonstrated that drinking water can be produced consistently and reliably on a large scale. This water is indirectly used to supply drinking water, with approximately 12.4 GL per annum of NEWater, around 1% of daily supply, blended into the raw water reservoir (http://www.pub.gov.sg/NEWater). 9

MAR to increase public drinking water supplies is used in a number locations in the United States and around the world. For example, the Hueco Bolson Recharge Project in Texas treats wastewater to drinking water quality, which is then injected directly into the primary drinking water source for the city of El Paso. At this site approximately 14 GL per year of treated wastewater is injected, of which half (7 GL) may enter drinking water supplies (Southwest Consortium for Environmental Policy and Research 1999). At Water Factory 21 in California, mentioned earlier in relation to preventing salt water intrusion, approximately 21 GL of secondary treated wastewater is further treated by microfiltration and reverse osmosis for injection into four coastal aquifers. Up to 5% (1 GL per year) of this water may return to the drinking water supply. To date there has been no evidence of any significant health risks from this practice (Australian Academy of Technological Sciences and Engineering 2004). The largest scale MAR project to provide drinking water in Europe is in the VeurneAmbacht region of Belgium. Approximately 2.5 GL per year of tertiary treated wastewater is infitrated into dunes following microfiltration and reverse osmosis. This water takes approximately 40 days to reach the aquifer, and is extracted at a minimum distance of 40 m from the edges of the infitration pond. This supplies an additional 2.5 GL of drinking water, constituting 40-50% of the regional drinking water demand (Johan Verbauwhede, IWVA, Intercommunale Waterleidingsmaatschappij van Veurne-Ambacht, personal communication).

3.2

National Context

At a national level, water availability and management is a critical issue. Australian domestic water use per person is second highest in the world, following the United States of America (Australian Academy of Technological Sciences and Engineering 2004). The Australian Water Services Association found that the country is facing a 275 GL shortage of drinking water in the next 10 years unless drastic conservation measures and new treatment methods are put into place. On 17 June 2005 it was reported in the Australian Newspaper that dam levels in eastern Australia were at record lows (The Australian, p 14, Cities have outgrown their dams). Sydney and Canberra have less than two years water supply left without further substantial rain, and Melbourne has only slightly more. Given this context, the Australian Academy of Technological Sciences and Engineering (2004) review of current trends in water recycling in Australia concluded that governments should recognise wastewater, stormwater and rainwater as additional water resources rather than disposal problems. It recommended that wider use of recycled water should be undertaken for applications where drinking water quality is not required. Increased water recycling is also supported by The Value of Water: Inquiry into Australia’s Management of Urban Water (Allison et al. 2002) and Recycling Water for Our Cities (Prime Minister’s Science, Engineering and Innovation Council 2003). A range of wastewater reuse projects are operational in Australia, both direct and indirect, with water sourced from both stormwater and treated wastewater. For

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example, in South Australia 20 GL per year of Class A water from the Bolivar Wastewater Treatment Plant is directly used in horticultural irrigation on the North Adelaide Plains. At Werribee in Victoria, the largest water reuse project in Melbourne, up to 8.5 GL of Class A water will be supplied to vegetable growers and the surrounding environment per year. This will increase the reliability of water supply for local growers and provide significant environment benefits to the area. At present, 22 MAR schemes are operational in the Adelaide region, injecting approximately 2 GL per year of rural and urban stormwater runoff into aquifers (Department of Water, Land and Biodiversity Conservation South Australia 2005). There are also a number of operational MAR schemes in Queensland. For example, at Bribie Island, up to 1.8 GL per year of secondary treated wastewater is discharged into three shallow ponds. This water forms a groundwater mound between the ocean and water supply trenches in order to prevent salt water intrusion into the scheme water supply (Resource Sciences and Knowledge 2000). While most MAR to date in Australia has been for applications with lower human contact, a MAR trial at the Greenfields Railway Station site in South Australia has recently commenced to examine the potential for recovering pre-treated stormwater to provide public drinking water supplies (Department of Water, Land and Biodiversity Conservation South Australia, 2005). In June 2005 the Goulburn Mulwaree Council made a submission to the Federal Government through its Water Smart Australia Program for funding of the Goulburn Mulwaree Council Sustainable Cities Project. This $32 million project aims to increase the secure yield of Goulburn’s water supply by reclaiming wastewater and returning it to the Sooley Dam catchment. The project includes: ? construction of a new wastewater plant; ? construction of an advanced water reclamation plant to produce drinking quality water for transfer to Bumana Creek watercourse and into Sooley Dam via a chain-of-ponds wetland; ? rehabilitation of the chain-of-ponds wetland system in Bumana Creek to polish the water before the final indirect recharge of the existing storage at Lake Sooley; and ? the provision of off takes from the transfer pipeline to allow urban reuse, including the Racetrack and sporting field irrigation (Parsons Brinckerhoff 2005). The Toowoomba City Council has also requested funding through the Water Smart Australia Program for the $68 million Toowoomba – Water Futures project. This includes: ? purifying 5000 ML per year of wastewater to a standard higher than drinking water and pumping this into Cooby Dam to supplement drinking water supplies; ? supplying the reject stream from the advanced water treatment plant to a coal mine after the reject stream has been mixed with a slightly higher quality water from the water reclamation plant; ? supplying 1000 ML per year of water from the advanced water treatment plant to a horticultural area;

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supplying 500 ML per year of reclaimed water to urban areas for non drinking uses; and ? supplying reclaimed water to meet future needs of a planned industrial estate. (Toowoomba City Council 2005). The Victoria Environmental Protection Authority ‘Use of Reclaimed Water – Guidelines for Environmental Management’ (2003) states that there is currently insufficient information available to develop generic guidelines, therefore proposals will be assessed on a case by case basis. In Queensland, guidelines are being developed which include indirect drinking water reuse of wastewater (Queensland Environmental Protection Agency 2004).

?

3.3

State Context

The climate of Perth is drying, with a significant reduction in rainfall measured in the south-west of Western Australia since the mid 1970s (Berti et al. 2004). Over the past 28 years, there has been a 10-20% reduction in rainfall in the south-west of the State, with a subsequent 40-50% reduction in runoff to dams, and reduced recharge of groundwater (Government of Western Australia 2003a). It is expected that climate change due to greenhouse gas emissions will continue to dry the climate in future (Water and Rivers Commission 2000). At the same time, the population of the Swan Coastal Plain, and therefore demand for water, is increasing. From 1985 to 2000, water use in Western Australia approximately doubled, to nearly 1800 GL per year, and groundwater use increased threefold (Water and Rivers Commission 2000). In Western Australia between 1999 and 2000, irrigated agriculture was the largest water user in the state, constituting 40% of the total state-wide demand. This was followed by the mining industry (24%), then household use (13%) (Water and Rivers Commission 2002), however not all of this is of drinking water quality. The total annual demand for water in the Perth metropolitan area is currently estimated at almost 600 GL, with approximately half of this being self-supply for irrigation and half for public scheme water (Government of Western Australia 2003a). A management strategy has been in place since 1994 to reduce demand for drinking water (Water and Rivers Commission 2002). This includes public awareness campaigns and water restrictions, such as two day per week sprinkler use. Demand management has succeeded in reducing summer demand for water, however the Australian Academy of Technological Sciences and Engineering (2004) considered that the success of demand management has ‘hardened’ water consumption, making it more difficult to achieve future savings either through efficiency gains or water restrictions. The Western Australia Water Assessment (2000) predicted that water use will double over the next 20 years (Water and Rivers Commission 2000). This is expected as a result of increasing population, along with increasing water use in the mining, industry and service sectors, and the estimate that irrigated agricultural use will more than double over this period (Government of Western Australia 2003a). Increasing demand for water, coupled with decreasing rainfall, has significant implications for water resource management, in particular the determination of sustainable yields and the allocation of water resources. Currently drinking water

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supplies in Perth are sourced from both protected surface and groundwater catchments, with approximately half from each source (Allison et al. 2002). The Western Australia Water Assessment (Water and Rivers Commission 2000) found that approximately one third of the State’s water resource systems are at a high or fully allocated level, with some areas being over-allocated. For the Perth groundwater division, it was reported that water use is at or near the sustainable limits, including the Gnangara and Jandakot superficial aquifers, and the Leederville and Yarragadee confined aquifers (Water and Rivers Commission 2000). In a number of groundwater sub-areas on the Coastal Plain there is no further groundwater currently available for allocation. Should the drying climate trend continue, it is likely that the current sustainable limits will be reduced. Figure 4 shows the decline in the Gnangara Mound, the largest and most important shallow groundwater resource in the Perth area, since 1979. In response to these issues and the need for a long term plan for water resource management, the State Water Strategy for Western Australia (Government of Western Australia 2003a) was developed. In this strategy, Government set a target of recycling 20% of wastewater by 2012. Recycling wastewater may allow for new water supply source developments to be postponed, wastewater disposal to the marine environment to be reduced, and high quality treated water to be retained for high value uses. Currently in the Perth region 3.3% (3.4 GL per year) of wastewater is recycled (Water Corporation 2002), with approximately 100 GL per year discharged to the marine environment (Government of Western Australia 2003a). This is predicted to grow to 160 GL by 2025, and exceed 200 GL by 2040 (Water Corporation 2005). The State Water Strategy identifies large-scale, scheme-based reuse options as a priority above reuse at a household scale in view of environmental, economic and health considerations. The Strategy highlights the potential for recycling to provide water ‘fit for purpose’ for irrigated horticulture, green space irrigation and industry, as well as the potential for MAR to increase water availability in groundwater systems, and to maintain environmental values. The major wastewater reuse project in Western Australia at present is the Kwinana Water Reclamation Plant, which came online in November 2004. The reclamation plant will reduce industry demand for scheme water by up to 6 GL per year. The plant takes wastewater from the Woodman Point Wastewater Treatment Plant, and treats it to Class A quality by filtration and reverse osmosis, producing water of a quality suitable for major Kwinana industrial customers. A form of MAR, using stormwater rather than wastewater, currently occurs in Perth with the infiltration of stormwater from residential roofs into soakwells and from roads into stormwater sumps. This accounts for approximately 80% of the stormwater in Perth, with the remaining 20% (120-130 GL per year) drained to rivers and the ocean outfalls (CSIRO submission 17 June 2005).

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Figure 4. Depletion of the Gnangara Mound since 1979 (Vogwill 2004) Several small-scale Water Corporation MAR projects using treated wastewater are currently operational, and a number of feasibility and pilot studies have been conducted. At the Kwinana, Geraldton and Halls Head Wastewater Treatment Plants, secondary treated wastewater is infiltrated and later withdrawn for use in irrigation. Also in Kwinana, Alcoa use groundwater supplemented by treated wastewater from the Kwinana Wastewater Treatment Plant (Water Corporation submission 28 June 2005). MAR trials have been conducted at Canning Vale (Edmonds et al. 1987), and feasibility studies undertaken at the Broome Wastewater Treatment Plant and on the Mosman Peninsula (SKM 1996, Australian Groundwater Technologies 2004). The Halls Head Indirect Reuse Scheme is a currently-operational MAR research and development plant (Toze et al. 2002, 2004). Treated wastewater is infiltrated into the shallow aquifer using infiltration basins. For a 24 month period, groundwater was monitored for potential environmental and health risks from major contaminants, particularly microbial pathogens, and for the influence of MAR on the local groundwater system (Toze et al. 2002). The CSIRO concluded that at this site the recovered MAR water is of suitable quality for irrigation purposes and has negligible health and/or environmental risks.

3.4

Principles of the Environmental Protection Act 1986

Any MAR proposal should have regard for the principles of the Environmental Protection Act 1986, as set out below. MAR is considered in the context of these principles in this section 16(e) advice. The precautionary principle Where there are threats of serious or irreversible damage, lack of full scientific certainty should not be used as a reason for postponing measures to prevent environmental degradation. In the application of the precautionary principle, decisions should be guided by -

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(a) careful evaluation to avoid, where practicable, serious or irreversible damage to the environment; and (b) an assessment of the risk-weighted consequences of the various options. The principle of intergenerational equity The present generation should ensure that the health, diversity and productivity of the environment is maintained or enhanced for the benefit of future generations. The principle of the conservation of biological diversity and ecological integrity Conservation of biological diversity and ecological integrity should be a fundamental consideration. Principles relating to improved valuation, pricing and incentive mechanisms 1. Environmental factors should be included in the valuation of assets and services. 2. The polluter pays principle – those who generate pollution and waste should bear the cost of containment, avoidance or abatement. 3. The users of goods and services should pay prices based on the full life cycle costs of providing goods and services, including the use of natural resources and the assets and the ultimate disposal of any wastes. 4. Environmental goals, having been established, should be pursued in the most cost effective way, by establishing incentive structures, including market mechanisms, which enable those best placed to maximise benefits and/or minimise costs to develop their own solutions and responses to environmental problems. The principle of waste minimisation All reasonable and practicable measures should be taken to minimise the generation of waste and its discharge into the environment.

4.
4.1

Factors
Sustainability

To be sustainable, development must meet the needs of current and future generations through an integration of environmental, social and economic goals (Government of Western Australia 2003b). Sustainability requires that the precautionary principle be employed where there is the risk of serious or irreversible environmental damage, and that intergenerational equity apply to ensure that the health, diversity and productivity of the environment be maintained or enhanced for the benefit of future generations. Increasing demand for water has traditionally been met by the development of new sources, such as the construction of dams. The environmental, social and economic costs of such approaches may be high, and in some cases these costs are seen as unacceptable (Allison et al. 2002). MAR should not be considered in isolation, but evaluated against the range of alternative water supply options, as required by the Precautionary Principle. This involves consideration of energy intensity, including requirements for water treatment and pumping, and other infrastructure. MAR should be considered as part of an integrated system.

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The EPA notes that MAR is consistent with the principle of waste minimisation. MAR is supported by the waste hierarchy defined in EPA Position Statement 7 ‘Principles of Environmental Protection’ (Environmental Protection Authority 2004), which places reuse and recycling above disposal. The Western Australian State Sustainability Strategy sets out several objectives with regard to the protection of drinking water and aquatic ecosystems. These objectives include: ? protect all drinking water catchments and all aquatic systems of high environmental/conservation, scenic and heritage significance; ? ensure that the abstraction of water does not exceed the water requirements of aquatic ecosystems; and ? provide for the protection of water-dependent ecosystems, while allowing for management and development of water resources to meet the needs of current and future users (Government of Western Australia 2003b). With regard to these objectives, MAR has the potential to increase the sustainable yields of aquifers by allowing recharge water to be used following a residence time in the aquifer, or by increasing water pressure in a confined aquifer and thus making other water available. The use of recycled water in this way has the potential to maintain groundwater dependent ecosystems, such as wetlands and caves, which are currently being impacted by declining groundwater levels. However, these potential benefits must be balanced against the risks, such as the potential for decreased water quality to adversely affect the environment. As part of the risk assessment for any MAR proposal, both the current and future beneficial uses of the environment should be considered. A balance should also be sought between the economic costs of treating water and the environmental costs associated with that water quality. Should the water quality requirement be so high that the project does not proceed, there is a risk that a potential environmental benefit may be lost. The EPA considers that increased wastewater recycling provides an opportunity to better and more sustainably manage water resources in Western Australia. However, the EPA notes that there is also a risk that, if not applied and implemented judiciously, there is the potential for MAR to be contrary to the principles of sustainability. As an example of this, MAR may provide the best means of maintaining groundwater dependent ecosystems on the Gnangara Mound for future generations. However, given the range of environmental issues associated with MAR, the implementation of schemes in areas of high environmental value may be incompatible with the precautionary principle. A high level of understanding of the potential impacts of MAR schemes would be required before considering any large scale proposals in such areas. Any MAR proposal referred to the EPA should address sustainability.

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4.2

Environment

4.2.1 Environmental Risks There are a number of environmental risks associated with MAR. Key risks relate to: ? groundwater contamination; ? surface and marine water contamination; and ? ecosystem degradation. Groundwater Contamination MAR has the potential to affect groundwater quality and flow. The recharge and abstraction of water may cause changes in groundwater levels, and may affect yield by changing the hydraulic parameters of the aquifer. The integrity of aquifer composition under conditions of long-term injection of wastewater has been identified by Scatena and Williamson (1999) as requiring further investigation. Treated wastewater may contain nutrients, such as nitrogen and phosphorus, at levels higher than in the native groundwater. It may also contain pathogens, heavy metals and chemicals. The concentrations of these contaminants will be dependent on the level of wastewater treatment prior to recharge. Some studies have also reported the potential for trihalomethanes to be formed when residual chlorine present in the recharge water continues to react with organic matter in the aquifer (Fram et al. 2003, Pavelic et al. 2005). This requires investigation with particular focus on the Swan Coastal Plain. The introduction of wastewater into an aquifer may induce geochemical reactions such as mineral precipitation, dissolution, cation exchange and redox reactions (Toze et al. 2001). These reactions have the potential to affect the adsorption or attenuation of metal or inorganic contaminants. For example, Appleyard et al. (submitted) postulate that MAR in the Gwelup area using wastewater with a high biochemical oxygen demand (BOD) could change groundwater chemistry, with the potential to cause acidification and the release of heavy metals from aquifer sediments. However, the CSIRO submit that the use of high BOD water would be impractical, causing microbial growth in the vicinity of the recharge site which would lead to clogging and therefore decrease recharge (CSIRO submission 17 June 2005). The EPA considers that this will be resolved in the development of specific proposals and through MAR trials. The potential for pathogens to survive and multiply in aquifers has been identified (Resource Sciences and Knowledge 2000), however it is expected that this is quite rare (CSIRO submission 17 June 2005). It has been reported that the number of organisms surviving in an aquifer declines at an exponential rate, depending upon a range of chemical, physical and biological processes, indigenous groundwater microorganisms and water chemistry (Toze et al. 2001). Site-specific data on pathogen survival will be necessary for the EPA to evaluate any large-scale MAR proposal for Class B and C schemes, particularly in cases when MAR is reliant on the aquifer to improve environmental water quality. For MAR schemes of Class A or above, the Department of Health require the absence of pathogens to be demonstrated.

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Changes in groundwater quality may affect subterranean fauna such as stygofauna and troglofauna. Stygofauna are aquatic subterranean animals, found in a variety of groundwater systems, while troglofauna occur in air chambers in underground caves or voids (Environmental Protection Authority 2003). The coastal karst system of the Swan Coastal Plain is known to contain a rich subterranean community. Changes as a result of MAR may be adverse, however there is also the potential that MAR using treated wasterwater may benefit stygofauna (CSIRO submission 17 June 2005). Stygofauna predominantly rely on the presence of bacteria and dissolved organic carbon for growth, therefore MAR may provide an environment suited to their growth. This requires further research. Surface and Marine Water Contamination MAR using treated wastewater may influence surface water quality as the recharge water moves into surface water bodies, with the potential for nutrient enrichment (eutrophication). For inland waters, the presence of phosphorus at certain concentrations has the potential to cause algal blooms in wetlands and streams. It is generally accepted that groundwater on the Swan Coastal Plain eventually discharges to the marine environment through surface flows and direct groundwater discharge. Appropriate management of MAR is therefore necessary to ensure that marine environmental values2 are protected. The outflow of nitrogen rich water into coastal marine waters may cause eutrophication (Government of Western Australia 2003c). Eutrophication of the marine environment in Western Australia has been documented in Cockburn Sound (DEP 1996) and Albany Harbours (EPA 1990), where proliferation of algae in the water column (i.e. phytoplankton) and on the leaves of seagrass (i.e. epiphytes) was attributed to excessive inputs of nutrients from industry and the catchment. In both locations, excessive growth of phytoplankton and epiphytes reduced light reaching seagrass leaves, ultimately leading to dramatic loss of seagrass and changes to fundamental ecological processes. Having a sound understanding of the mechanisms of groundwater flow to the marine environment is important for MAR. For example it is possible that where karstic limestone occurs as part of the nearshore geology, solution pipes could potentially provide preferential groundwater flow direct to the marine environment. While it is possible that, depending on water treatment prior to MAR, nitrogen loads to the marine environment may be reduced by discharging treated wastewater to groundwater for MAR, the potential for impacts from other contaminants (e.g. toxicants), where concentration rather than load affects marine biota, may be increased because there is no dilution through a diffuser. This requires consideration in planning any MAR scheme. The EPA also recognises that the level of wastewater treatment prior to MAR may have implications for the marine environment. Reverse osmosis of wastewater is one high-level treatment option being explored by the Water Corporation to minimise
2

Particular values or uses of the environment that are important for a healthy ecosystem or for public benefit, welfare, safety or health which require protection from the effects of pollution, waste discharges and deposits (NWQMS: ARMCANZ /ANZECC 1994).

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potential for contaminants to enter aquifers. A by-product of the reverse osmosis process is a concentrated waste stream which will require disposal. If a decision were to be taken to discharge reverse osmosis waste products directly to the marine environment, it should be recognised that while the total load of contaminants is unchanged, as compared with traditional ocean disposal of wastewater, the concentrations of contaminants in the waste stream will increase and the mixing and dispersion characteristics of the more concentrated effluent may be altered. The environmental significance of the issues outlined above will be dependent on factors including the method and level of wastewater treatment prior to MAR, biogeochemical processes acting on treated wastewater in the aquifer, the mode and rate of discharge, and the characteristics of the receiving environment. Ecosystem Degradation MAR using treated wastewater has the potential to affect ecosystem values in groundwater and other systems, such as wetlands. One of the key concerns is the introduction of chemicals. Chemicals of concern include endocrine disruptors, pharmaceutically active products and personal care products (such as sunscreen and soaps). Endocrine disruptors are exogenous substances that interfere with the structure and function of the endocrine system, causing effects largely through interaction with hormone receptors of the affected organism (Toze et al. 2001). These have been associated with developmental, reproductive and other health problems in wildlife and laboratory animals. Chemicals in wastewater may survive in waterways for several years, and in some cases may interact with other chemicals in the environment to form new compounds (Allison et al. 2002). The Inquiry into Australia’s Management of Urban Water (Allison et al. 2002) found that the extent to which pharmaceutically active chemicals constitute a problem in Australia is difficult to ascertain. Ecosystem protection values for chemicals require separate consideration to values for the protection of human health, as these are not necessarily sufficient to protect environmental values. The CRC for Water Quality and Treatment, Occasional Paper 7, Review Of Endocrine Disruptors In The Context Of Australian Drinking Water (Falconer et al. 2003) states that concentrations of endocrine disruptors in domestic wastewater may cause changes in aquatic fauna. The levels involved are orders of magnitude less than the concentrations likely to cause detectable health effects in humans if this water is a component of drinking water. The potential for endocrine disruptors and pharmaceutical products to cause aquatic environmental damage has only recently been recognised, and information on their effects is relatively scarce. This is currently an active area of research. The EPA notes that the concentrations of chemicals are related to the level of wastewater treatment. A variety of advanced treatment technologies have been shown to significantly increase the quality of treated wastewater (e.g. Chapman 2003), thereby decreasing the number of chemicals of environmental concern in the water. However further research in this area is needed, particularly with regard to environmental and ecotoxicological impacts. The Department of Fisheries advise that the potential for these chemicals to cause aquatic damage has only relatively recently

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become recognised and information on their effects is scarce and often of poor quality (Department of Fisheries, letter 22 November 2004). With regard to ecosystem values, the EPA notes that the Department of Environment encourages research on potential contaminants in treated wastewater (DoE submission 9 September 2005). This includes methods to accurately estimate their presence and quantities, and the establishment of an environmental risk assessment framework to assess any contaminants that are likely to be detected and interact in groundwater dependent ecosystems. A further environmental issue associated with MAR using treated wastewater is the potential for heavy metals to accumulate in soils. Heavy metals are easily and efficiently removed from wastewater during common treatment processes, however in some cases, such as wastewater from an industrial source, there is the potential that they may become bioavailable. This requires further research. 4.2.2 Environmental Benefits MAR projects may be proposed for two key environmental purposes: ? improvement in water quality; and ? environmental water allocation. Improvement in water quality Infiltration or injection of treated wastewater into a groundwater aquifer may improve the quality of the recharge wastewater by physical, chemical and biological processes in the aquifer. For example, the soil may act as a filter, removing suspended solids, biodegradable materials and micro-organisms. Residence time in the aquifer may also allow for the die-off of microbial pathogens and their removal by indigenous native groundwater micro-organisms, and the attenuation of chemicals such as organics. When the injected water is of a higher quality than the native groundwater, this may produce a net improvement in water quality through dilution or the promotion of favourable geochemical reactions (Centre for Groundwater Studies 1999). For example, in South Australia saline and brackish aquifers have been freshened by MAR with seasonally available fresh water. This water is then suitable for use in irrigation during the dry months (Pyne 1995). Another potential application of MAR is to prevent salt water intrusion in coastal aquifers. Salt water intrusion can occur when fresh groundwater is withdrawn at a greater rate than it is replenished, allowing salt water from the ocean to intrude into the fresh water aquifer. This may lead to the aquifer becoming salty and unsuitable as a source of drinking or irrigation water. MAR may be applied in such areas to create a hydraulic barrier to the salt water. This excludes salt water from the aquifer as the recharge water moves towards the coast. Environmental water allocation MAR using treated wastewater may be used to restore groundwater levels in areas where these have been lowered, with the potential to restore the environmental values of systems such as wetlands or caves. MAR may also free up allocations of water to allow rivers, wetlands or vegetation to be maintained or restored.

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Treated wastewater may be used in irrigated horticulture, having the potential to significantly decrease horticultural water requirements from other sources and provide public drinking water or groundwater benefits. In cases where recycled wastewater is used for horticultural applications, the nutrients in recycled water may lessen the requirement for commercial fertilisers. Given the drying climate of the south-west, MAR may present a means of protecting groundwater dependent ecosystems and preventing acidification due to the drying of acid sulphate soils.

4.3

Public Health

Health risks include both microbiological and chemical risks. The major microbiological risk is infection from viruses, bacteria, protozoa and helminths. The risk associated with chemicals is adverse health effects following prolonged human exposure (ARMCANZ/ANZECC 2000a). In order to manage these risks, the Western Australia Department of Health (DoH) has developed draft Recycled Water – Groundwater Recharge Guidelines (2005) which will apply to any MAR scheme using treated wastewater. These Guidelines are attached in Appendix 2. The general principles underpinning MAR schemes will need to be met irrespective of the end use proposed. The extent of compliance with monitoring and drinking water quality guidelines required for individual schemes will be proportional to the human exposure and subsequent public health risk. The DoH Guidelines are based on the following principles: A number of principles underpin the derivation of health guidelines for aquifer recharge settings and these must be addressed in any proposal. They are: 1. All schemes must be individually approved although new users may be added to a scheme if the proposed new use is of an equivalent or lesser human exposure level. 2. All schemes must adopt a risk management framework. 3. All schemes are approved on a “fit for purpose” basis. The allocation of any proposed scheme to a “fit for purpose” category is based on the extent of human exposure and the subsequent modelled risk. For example, all aquifer recharge schemes involving indirect potable use are assumed to have an ingestion exposure of two litres per day for 70 years. 4. Requirements will include both quality and process components 5. All schemes require three types of monitoring. 5.1. Validation (will it work): this may include chemical and pathogen testing to demonstrate effectiveness of removal processes however surrogates can be

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used to demonstrate this (eg MS2 phage)3. Validation testing is based on obtaining a sufficient database to provide convincing evidence that a process or method will work. 5.2. Operational Testing (is it working): this will include a series of measurements and observations to confirm performance of preventative measures. Operational monitoring is based on the need to allow timely intervention and can be both continuous (disinfection, filtered water turbidity) or six monthly (inspection of structures). 5.3. Verification (did it work): this may include testing for chemicals and microorganisms. The frequency of required monitoring is based on an assessment of need, and is based on notional ideas about the variability of water quality characteristics system complexity and other perceptions. 6. The water extracted from the aquifer after the recharge process must be of a required quality without extra treatment being necessitated. 7. While a risk management approach is required for all aquifer recharge proposals, for those involving indirect potable reuse, the best available technology is also mandated and must include a reverse osmosis component. 8. The major health issues of concern are chemicals and pathogens, including viruses, bacteria, helminths, and parasites. Overseas work has demonstrated the relative unimportance of heavy metals and radiation although local validation of this will be required. Chemicals are only a concern for indirect drinking water schemes. 9. Separation times will be required between recharge and extraction for all proposals involving indirect potable re-use. Minimum times based on the mode of recharge will be identified. These will be shorter for infiltration compared to injection but, in all cases, the longer the time between recharge and extraction, the greater the margin of safety. Minimum separation distances between infiltration or injection and extraction will also be required. Separation times will also be required for class A schemes such as horticulture, if these have been approved without a requirement for full treatment prior to spreading. In setting health guidelines for MAR, the Department of Health has taken account of the current development of national guidelines for wastewater reuse and guidelines in place in MAR schemes elsewhere in the world. The Department of Health believes that wherever possible local guidelines should reflect best practice described in national and international policies. The Department of Health does however recognise that in this instance, pressures in Western Australia for consideration of MAR for source development put the local health debate well ahead of national processes. In addition, pressures on source development in international communities may lead to the guidelines that are deemed inadequately protective in a Western Australian setting.
MS2 phage is a bacteriophage or a virus that infects bacteria. These bacteriophages are easier to grow and propagate than viruses which infect man and are used to test how other viruses would act when these viruses can’t be examined directly. MS2 phage, a single stranded RNA virus, has been used in many water reuse schemes to monitor how, more difficult to assess, human viruses of concern would be affected.
3

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4.4

Regulatory Requirements and Guidelines

The Commonwealth is involved in water management in Australia through the National Environmental Protection Council Act 1994, and the Environment Protection and Biodiversity Conservation Act 1999. Constitutional responsibility for recycled water rests with the States and Territories (Australian Academy of Technological Sciences and Engineering 2004). The National Water Quality Management Strategy provides a series of national guidelines for water quality management at a federal level. This is supported in Western Australia by the State Water Quality Management Strategy, 2001 (Government of Western Australian 2003c). The National strategy is comprises 21 guideline documents for water quality management, including the Australian and New Zealand Guidelines for Fresh and Marine Water Quality (ARMCANZ/ANZECC 2000c). Two Guidelines are directly relevant to MAR: Australian Guidelines for Sewerage Systems – Effluent Management (ARMCANZ/ANZECC 1997) and Australian Guidelines for Sewerage Systems – Reclaimed Water (ARMCANZ/ANZECC 2000a). The National Resource Management Ministerial Council is currently developing National Guidelines For Water Recycling, expected to be released for public comment in late 2005. These will consist of a suite of documents including a Framework for Management of Recycled Water Quality and Use and documents which provide specific criteria and guidance for health and environmental parameters relating to identified priority uses. Additionally, the Australian Guidelines for Water Quality Monitoring and Reporting (ANZECC/ARMCANZ 2000b) are relevant to MAR as they provide methodologies for setting quality objectives for surface and groundwater. In 1982 the Australian Water Resources Council published guidelines on the use of reclaimed water for aquifer recharge. These guidelines were updated in the 1996 Guidelines on the Quality of Stormwater and Treated Wastewater for Injection into Aquifers for Storage and Reuse (Dillon and Pavelic 1996). These guidelines recommend that the level of groundwater protection should be dependent on the potential beneficial uses of the native groundwater, and therefore on current groundwater quality. The EPA notes that such a differential protection policy is unlike policies in many other parts of the world, as it does not assume drinking water quality as an essential objective. This takes into account that much groundwater in Australia is too saline for drinking water supplies, and also that the allowable concentrations of some contaminants, such as phosphorus, are lower for ecosystem protection than for drinking water supplies (Dillon and Pavelic 1998). In Western Australia, water resources are managed by the Water and Rivers Commission (Department of Environment). Under the Rights in Water and Irrigation Act 1914, the right to use, flow and control groundwater is vested in the Crown. This Act requires the licensing of all wells abstracting from aquifers in proclaimed Groundwater Areas, and all artesian wells. Public Drinking Water Source Areas (PDWSAs) are proclaimed and protected from contamination risks through the Metropolitan Water Supply, Sewerage and Drainage Act 1909 and Country Areas Water Supply Act 1947, administered by the Water and Rivers Commission. PDWSA

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is the collective description for Underground Water Pollution Control Areas, Water Reserves, and Catchment Areas declared under the above Acts. PDWSAs are classified into three groups: Priority 1 areas are managed in accordance with the principle of risk avoidance to ensure no degradation of the drinking water source; Priority 2 areas are defined to ensure that there is no increased risk of pollution to the water source, and Priority 3 areas are where it is practical to manage the risk of pollution to the water source. By-laws under the above Acts enable the management and control of specified potentially polluting activities and land uses. Accordingly, the Department of Environment will be a decision maker through its legislative responsibilities for MAR proposals. The extent of its decision making powers is still to be determined for MAR and it may vary depending on the proposal. The Department of Environment is also developing a management policy for MAR in the 2005-06 financial year. It is expected that options for trading and/or cost recovery of MAR schemes would form part of the policy (Department of Environment submission 27 June 2005). MAR proposals will be considered under the provisions of the Environmental Protection Act 1986. Under Part III of the Environmental Protection Act 1986, the Environmental Protection (Gnangara Mound Crown Land) Policy 1992 applies on the Gnangara Mound. The policy aims to protect the level and quality of groundwater, native vegetation and wetlands in this area by controlling activities that cause the quality of groundwater to be decreased. The discharge of contaminants in the policy area is only permitted if done so under authorisation of the Environmental Protection Act 1986. This includes authorisation following assessment of a proposal by the EPA, or the decision of the EPA not to assess. This policy is due to be updated. Part IV of the Environmental Protection Act 1986 provides for the assessment of proposals considered likely to have a significant environmental impact. This is discussed further in Section 5. MAR proposals may also be subject to Part V of the Act. This part of the Act regulates discharge through works approvals and licences. The Government policy context underpinning the evaluation of the potential impacts of MAR on the marine environment is provided in the State Water Quality Management Strategy (SWQMS) Document No 6 (Government of WA, 2004), which is based on, and consistent with, the National Water Quality Management Strategy documents. The framework described in the SWQMS No. 6 involves identifying Environmental Values and Environmental Quality Objectives and clearly setting out where they do and do not apply through consultation with the community. Environmental Quality Criteria are the numerical and/or narrative benchmarks which are used in combination with results of environmental monitoring to gauge whether management strategies are effective in protecting the Environmental Values. The EPA is implementing the environmental quality management framework described in SWQMS No. 6 in the marine environment through its policy formulation (e.g State Environmental (Cockburn Sound) Policy, 2005) and environmental impact assessment roles under the Act. Consistent with the SWQMS, the EPA, through consultation with the community, has established a set of EVs and spatially defined boundaries for the Environmental Quality Objectives in the State marine waters between Mandurah and Yanchep.

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Proposals with the potential to either positively or negatively impact on coastal waters will be considered by the EPA in the context of the Environmental Values and Environmental Quality Objectives set out in Perth’s Coastal Waters Environmental Values and Objectives (Environmental Protection Authority 2000). Potential impacts on the Swan or Canning rivers should be assessed against the management targets set out in the Swan Canning Cleanup Program (Swan River Trust 1999). State and Local Government planning processes exist to protect water sources through the Western Australian Planning Commission’s Statement of Planning Policies (for example, Statement of Planning Policy No. 2: Environment and Natural Resources Policy, and Statement of Planning Policy No. 2.7: Public Drinking Water Source Policy). These policies are prepared under provisions in the Town Planning and Development Act 1928. Amendments may also require approval under the relevant Metropolitan Regional Scheme and/or Local Government Town Planning Scheme. The EPA also notes that Planning (or Development) Approval may be required for any development works which may be involved with MAR proposals. The Health Act 1991 includes provisions to protect public health in relation to the consumption of drinking water. Approval by the Department of Health is required for any water recycling in Western Australia under sections 97, 107 2 (b) and 129 of the Health Act 1911. Under this Act, it is an offence for any person to pollute any water supply or water catchment containing water intended for human consumption. The Economic Regulation Authority (ERA) is responsible for the licensing of water service providers to ensure the delivery of safe water. The Water Division of the Economic Regulation Authority is responsible for the functions outlined in section 4 of the Water Services Licensing Act 1995. These functions consist of licensing water service providers and monitoring the performance of water industry service providers. In addition, the Minister may refer to the ERA an inquiry on water issues. The Water Division would be responsible for managing this inquiry. The ERA licenses water service providers in Western Australia, setting out the conditions by which water and wastewater services operate. The ERA also benchmarks water providers to evaluate business performances and to encourage water providers to gain efficiencies and improve performance.The Commonwealth Department of Environment and Heritage may be involved in MAR proposals under the Environment Protection and Biodiversity Conservation Act 1999.

4.5

Aboriginal Heritage

The Western Australia Department of Indigenous Affairs (DIA) provided advice (DIA, letter 26 April 2005) that MAR proposals may impact on Aboriginal sites. DIA recommend that a comprehensive Aboriginal heritage study of any MAR area be undertaken, including desktop studies to identify any previously registered Aboriginal heritage sites within MAR areas. DIA also advised that an archaeological and ethnographic survey should be undertaken in consultation with the Aboriginal community. It is DIA’s preference that Aboriginal sites are avoided. Where this is not possible, the proponent may seek the consent of the Minister for Indigenous Affairs to use the land under section 18 of the Aboriginal Heritage Act 1972.

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4.6

Community Involvement

There is a high level of support for the concept of water recycling, with unfavourable attitudes generally found to be more likely with a higher level of human contact or proximity to the application (ARMCANZ/ANZECC 2000a). Community involvement from the initial planning stages will be important to allow any concerns to be identified and addressed. The Water for a Healthy Country National Research Flagship recently released a report ‘Predicting Community Behaviour in Relation to Wastewater Reuse – What Drives Decisions to Accept or Reject?’ (Po et al. 2005). This reports on a three year investigation which attempted to develop a measure of community intended behaviour in relation to wastewater reuse. It includes the results of a case study of providing drinking water using MAR in Perth, in which 400 people were surveyed regarding their intended behaviours. The EPA recommends proponents of MAR schemes consider the findings of this report prior to the design of a community involvement plan. Any MAR proposal subject to environmental impact assessment under section 38 of the Environmental Protection Act 1986 will require a high level of community consultation. The EPA notes that it may be preferable in some cases that consultation and/or peer review of proposed schemes is carried out by an independent third party.

5.
5.1

EPA Advice
Overarching advice

The EPA is of the view that MAR using treated wastewater has the potential to play an important role in the sustainable management of Western Australia’s water resources. This is particularly the case given the reduction in rainfall which has occurred in the south west of the State since the mid 1970s, and the large reliance on groundwater resources. There are a number of potential environmental, health and social issues associated with MAR, and these will need to be addressed prior to the implementation of any significant MAR scheme. The use of MAR has the potential to provide benefits for water resources and environmental management. These include maintenance of wetlands and caves, reduced salt water intrusion, increased water availability for irrigation use, and augmentation of drinking water supplies. The EPA recognises that it will not be possible to implement MAR using treated wastewater without some degree of risk. These risks should be assessed against the potential environmental and sustainability benefits of MAR schemes, and the risks associated with taking no action. The EPA expects that in a number of situations, the risks associated with MAR can be managed to negligible or low levels to provide, on balance, a number of benefits for water resources and environmental management. The specific environmental risks associated with MAR are highly dependent on the proposal characteristics. These include the proposed wastewater treatment process, the intended final use of the recharged water, the environment likely to be impacted, aquifer characteristics, and the proposed management system. Proponents of MAR 26

schemes will be required to perform a systematic risk assessment of their proposals. The EPA understands that the National Guidelines on Water Recycling (National Resource Management Ministerial Council), to be released for public comment in late 2005, will also support a risk management framework. The EPA recommends a staged approach to MAR, starting with trials and projects of lower risk. Given the limited experience with MAR on the Swan Coastal Plain to date, and the site-specific nature of transport and attenuation of contaminants, the EPA expects that trials will be necessary prior to the implementation of any large scale MAR using treated wastewater. The EPA supports the principles of the National Water Quality Management Strategy (ARMCANZ/ANZECC 1997, 2000a, 2000b), and has been given the task by Government of coordinating the implementation, and reporting on the success, of the framework for protecting the State’s water resources which is set out in the State Water Quality Management Strategy Document No. 6 (Government of Western Australia 2004), which provides a national framework for the protection of groundwater resources. The goal of groundwater protection is to ensure that groundwater resources can support their beneficial uses in an environmentally, economically and socially sustainable and acceptable manner. Beneficial uses include abstraction for irrigation and stock, and maintenance of ecosystems, both in environment receiving groundwater discharge and within the aquifer itself. The EPA will not support MAR where it is considered likely, on the basis of risk assessment, to unacceptably affect the beneficial uses of groundwater or any other identified beneficial uses. The EPA expects proponents of MAR schemes using treated wastewater to demonstrate that the recharge water is chemically and microbiologically compatible with the native groundwater. At the point of withdrawal or movement into marine or terrestrial water bodies supporting defined EVs, the recharge water should meet the relevant environmental water quality guidelines for protecting the designated Environmental Values of the water. In cases where MAR is reliant on the treatment of water by natural processes in the aquifer, EPA support will be dependent upon whether risk assessment provides assurance that the scheme will not cause unacceptable degradation of the aquifer or the marine environment, or detrimentally affect the beneficial use of the resource. While there is currently no specific environmental legislation relating to MAR, it is the view of the EPA that Part V of the Environmental Protection Act 1986 provides a suitable regulatory mechanism for managing the daily operation of MAR schemes. Any MAR proposal that is likely, if implemented, to have a significant effect on the environment should be referred to the EPA under section 38 of the Environmental Protection Act 1986 for environmental impact assessment. At this time the EPA considers that any large-scale MAR using treated wastewater, or proposals for MAR or trials in areas of high environmental value, are likely to require formal assessment. The EPA expects that its assessment of such proposals would be informed by the results of scientifically sound studies to predict mixing and dispersion of discharges of MAR water and wastes, as well as the ecological and health-related consequences of these discharges. The EPA will apply the framework described in the State Water

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Quality Management Strategy No. 6 when evaluating the potential marine environment impacts of MAR proposals. The EPA may also develop an environmental management framework for the protection of groundwater and maintenance or enhancement of groundwater resources as the results of further research and trials become available. This would involve identification of Environmental Values and the development of Environmental Quality Objectives (management goals) to protect these values. Such a system would allow for the management of cumulative effects, as done for Perth’s Coastal Waters (Environmental Protection Authority 2000). MAR proposals require Department of Health approval under the Health Act 1911, in addition to planning approvals.

5.2

Potential Applications on the Swan Coastal Plain

There are a number of potential applications of MAR using treated wastewater on the Swan Coastal Plain that may prove to be technically feasible. A brief description of five key applications was included in the EPA’s Discussion Paper for public comment (Environmental Protection Authority 2005), and is provided here along with the EPA’s initial considerations due to the lack of details on these applications at this time. A summary of the potential applications, their risks and benefits and the key regulatory standards and processes, is provided in Table 2. The EPA notes that the technology exists to provide engineering solutions to a large number of the water quality issues associated with MAR. However, for many MAR applications it may be cost prohibitive to treat wastewater to a high level. The issues of concern to the EPA will be dependent on a number of factors, including the proposed level of wastewater treatment and characteristics of the recycled water proposed to be used in MAR. MAR for Improvement of Groundwater Quality MAR to improve groundwater quality and prevent salt water intrusion may have application on the Mosman-Cottesloe Peninsula, containing the suburbs of Mosman Park, Cottesloe and Peppermint Grove. This area is underlain by a thin fresh groundwater lens overlying salt water. The Peninsula is subject to salt water intrusion as a result of abstraction of groundwater by a number of large water users, including golf courses, park and recreation reserves and private schools. Appleyard (2003) estimates that the amount of freshwater beneath the Cottesloe peninsula has been reduced by about 40% due to groundwater abstraction. In 2003, groundwater salt levels reached a record high. The average salinity reached 1460 parts per million (ppm) in January, and peaked at 2600 ppm, the highest since monitoring began in 1996 (Post Newspaper 2004). Salinity of 1200 ppm was reported as being likely to kill many garden plants, while Norfolk Island pines can tolerate salinity of approximately 1100 ppm.

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Table 2. Summary of key issues and requirements related to potential MAR applications
MAR Application 1 Improvement of groundwater quality Key Risks - Environmental impacts e.g. eutrophication, Fish Habitat Protection Area - Chemicals of concern Potentially low attenuation of contaminants due to karstic limestone subsurface - Environmental impacts - Chemicals of concern - Impacts on other beneficial uses Priority 3 PDWSA to west Key Benefits - Reduce salinity in freshwater aquifer - Reduce salt water intrusion REGULATORY STANDARDS/PROCESS HEALTH ENVIRONMENT Criteria Legislative role Criteria Legislative role Likely Class A - Health Act 1911 - Potential for human exposure, uncontrolled access NWQMS TBD - Part III and V EP Act - Swan Canning EPP - Coastal Zone SEP (in prep) EPA role and comments Likely to require assessment

e.g. Mosman Peninsula

- Increased water availability - Reduce use of drinking water for irrigation

2 Irrigated horticulture

-Manage declining water tables - Reduce risk of acid sulphate soils

Class A

- Health Act 1911 - Potential for human exposure, uncontrolled access

NWQMS TBD

e.g. Carabooda

Increased opportunity for horticulture in Gnangara Potentially Class B Controlled access

- Part III and V EP Act - Lakes EPP - Gnangara EPP - Clearing Regs - Swan Canning EPP Approval under MWSSD Act if in PDSWA

Large-scale proposals require referral to the EPA

Likely to require assessment EPA assessment dependent on potential environmental impacts

e.g. small scale horticulture with single or several users 3 Multiple benefits

- Maintain or improve environmental features currently impacted by lowered water tables - Increase sustainability of horticulture - Reduce risk of acid sulphate soils

Class A

- Health Act 1911 - Potential for human exposure, uncontrolled access

NWQMS TBD

- Part III and V EP Act - Lakes EPP - Clearing regs - Gnangara EPP - Swan Canning EPP - Lakes EPP

Large-scale proposals require referral to the EPA

e.g. Gnangara Mound 4 Integrated water management in new residential areas

- Environmental impacts, e.g. groundwater dep

- Reduce consumption of higher quality water for low quality requirement activities

Class A

- Health Act 1911 - Potential for human exposure,

NWQMS TBD

- Part III and V EP Act - Lakes EPP - Clearing regs

EPA assessment dependent on potential environmental impacts

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MAR Application

Key Risks ecosystems - Impacts on other beneficial uses Priority 1 and 3 PDWSA in proximity to MAR sites - Environmental impacts - Impacts on beneficial uses - Protection of drinking water source - acceptability to community Existing Priority 1 PDWSA – priority value of area for drinking water

Key Benefits (e.g. irrigation) - Reduce risk of acid sulphate soils

REGULATORY STANDARDS/PROCESS HEALTH ENVIRONMENT Criteria Legislative role Criteria Legislative role uncontrolled access - Gnangara EPP - Coastal Zone SEP - Swan Canning EPP

EPA role comments

and

e.g. Alkimos

5 Increase drinking water supplies

- Increase public drinking water supplies - Maintain or improve environmental features currently impacted by lowered water tables - Reduce risk of acid sulphate soils

Class A+

- Health Act 1911 - Augmentation of drinking water supplies following MAR. - Health biological and chemical guidelines

- NWQMS - ADWG - TBD

- Part III and V EP Act - Approval under MWSSD Act (if in PDSWA) - Lakes EPP - Clearing regs - Gnangara EPP - Swan Canning EPP

Further information and studies of MAR on the SCP is necessary before EPA would support MAR in a PDWSA

e.g. Pinjar borefield

Formally assess

Note this table presents only the key requirements related to each of these scenarios. For the complete list of legislative requirements refer to Section 4. Only additional factors are listed for each specific application example. ADWG EP Act EPP MWSSD Act NWQMS PDWSA SEP TBD Australian Drinking Water Guidelines Environmental Protection Act 1986 Environmental Protection Policy Metropolitan Water Supply, Sewerage and Drainage Act 1909 National Water Quality Management Strategy Public Drinking Water Source Area State Environmental Policy Further criteria To Be Determined by the Department of Environment

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In order to reduce salinity and increase the availability of groundwater suitable for irrigation, tertiary treated wastewater from the Subiaco Wastewater Treatment Plant could be used to recharge the superficial aquifer underlying the Mosman Peninsula by subsurface infiltration. The Water Corporation estimates that 0.5 GL of recharge per annum would be used by private irrigators from backyard bores, and 2.5 GL per annum for large greenspace irrigators, such as golf courses. One of the key environmental risks associated with such a proposal is the potential for eutrophication of groundwater or surface water ecosystems, in particular the Swan River and the near-shore ocean. The importance of this issue would be dependent upon the characteristics of the wastewater prior to recharge. It is possible that MAR into a fractured limestone subsurface may provide little attenuation in contaminant concentrations due to preferential flow. The EPA also notes the complexity of predicting solute transport in fractured media. MAR on the Mosman-Cottesloe Peninsula may have implications for the Cottesloe Reef Fish Habitat Protection Area, which was established to protect the biodiversity of this ecologically significant area. Groundwater discharge from coastal seepage faces and offshore springs may have an important role in sustaining biological diversity on wave-cut platforms that fringe part of the coastline of the area (Appleyard, personal communication). The Water Corporation however submit that Western Australian waters are so nutrient poor that additional nutrients would be likely to enhance primary production and benefit fisheries (Water Corporation submission 28 June 2005). Further investigation of this would be required in order for the EPA to assess this proposal. The Department of Health advises that the level of treatment required for groundwater quality improvement will be dependent on the likelihood of extraction for backyard bores or other forms of human contact. If there is no possibility of human exposure, MAR for the improvement of groundwater quality does not need to meet any Department of Health guidelines. In the case of this application, the public could access the aquifer via private bores, and plausibly use this water for vegetable growing or filling swimming pools. Also children playing in yards may drink it. Therefore all pathogen guidelines must be met. It is assumed that exposure in this setting will remain limited and casual, so there is no technical requirement to meet chemical guidelines for human water consumption. A demonstration of a seven log reduction4 in pathogens is required if wastewater is the source of recycled water. An equivalent log reduction would be required for recycled water sourced from greywater or stormwater. The Department of Health will permit the required log reductions to be demonstrated in the unsaturated zone for infiltration recharge schemes. The number of log reductions required may be reduced if local data are developed demonstrating consistent microbiological reduction activity in local aquifers.

A measure of effectiveness of a process to remove certain viruses or bacteria. Each log reduction reduces the number of infectious units (e.g. viruses or bacteria) by a factor of 10. For example, one log reduction reduces the original level by 90%, two log reductions reduces the original level by 99%, three by 99.9%, etc.

4

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The EPA notes that the Water Corporation submission (22 August 2005) states that based on current knowledge and advice from Department of Environment, the Water Corporation has made the decision not to investigate MAR on Mosman Peninsula further at this time, as it does not consider it possible to provide the level of certainty required to get approval for this scheme. The EPA notes that the Water Corporation submission (22 August 2005) states that based on current knowledge and advice from Department of Environment, the Water Corporation has made the decision not to investigate MAR on Mosman Peninsula using treated wastewater further at this time, as it does not consider it possible to provide the level of certainty required to get approval for this scheme. Supply of excess drainage water, however, is likely to be more viable, and Water Corporation will continue investigations regarding the potential for supply from Herdsman Main Drain to address water needs for the Mosman Peninsula via MAR. Conclusion: The EPA supports in principle the concept of MAR to improve groundwater quality, but considers that further research would be required in order to evaluate any specific MAR proposal for this purpose due to the potential for environmental impacts. MAR for Irrigated Horticulture The Carabooda area, located on the Gnangara Mound north of Wanneroo, is the major market gardening region north of Perth. As a result of climate change, water use by nearby pine plantations, and a large amount of abstraction, groundwater levels have declined by up to 5 metres over the last 25 years. This has impacted remnant bushland areas and a number of important groundwater dependent ecosystems including the Yanchep caves root mat communities, Loch McNess, Lake Wilgarup, Lake Yonderup, Lake Nowergup and Coogee Springs. MAR using treated wastewater could be implemented to manage declining water levels and provide water for sustainable irrigation in horticultural areas. This has the added advantage that wastewater contains elevated levels of nutrients, and thus may decrease fertiliser requirements. Conceptually, treated wastewater could be piped from either Beenyup or proposed Alkimos Wastewater Treatment Plant to the eastern (upgradient) side of the horticultural precinct to be recharged into the unconfined superficial groundwater aquifer. Horticulturalists would be able to extract the recharge water from the superficial aquifer using existing private bores. Currently approximately 10 GL per year of superficial groundwater is allocated to horticulture in Carabooda. There is the potential for MAR to supply up to 20 GL per annum of treated wastewater, including some environmental allocation. In considering this potential application, the EPA notes that irrigated horticulture using wastewater is relatively common around the world. For example, in the Northern Adelaide Plains of South Australia over 20 GL per year of wastewater from Bolivar Wastewater Treatment Plant is used directly in irrigated horticulture. The wastewater is treated to be suitable for unrestricted horticultural use, including spray irrigation of salad crops (Australian Academy of Technological Sciences and Engineering 2004). Produce grown with recycled water in South Australia, Victoria, 32

New South Wales and Queensland are sold in markets both nationally and internationally (Jim Kelly, personal communication). The use of MAR, as opposed to direct piping of treated wastewater, allows for water quality improvement in the aquifer during storage, for example pathogen die-off, and provides a means of storing the recycled water to meet seasonal demand. However, there is greater potential for environmental impacts. The EPA considers that the key environmental issues requiring further investigation prior to implementation of a large-scale MAR scheme for horticulture are: o water quality improvements during MAR, if improvement is required during storage in the aquifer; o pathogen survival; o impacts on the aquifer, for example, as a result of changes in the aquifer chemistry; o impacts on wetlands and ecosystem values, including stygofauna, particularly due to chemicals; and o the potential for bioaccumulation of heavy metals. The EPA also notes that there is a need for consideration of water use efficiency in the horticultural industry. MAR should not be viewed as a panacea to water shortages or an opportunity to increase abstraction, placing pressure on other environmental values. The Department of Health advise that the level of treatment for horticultural areas is dependent on the type of horticulture and the extent of possible human exposure. For ready to eat produce, without a further disinfection or processing step, e.g. lettuces, an assumption is made that human exposures of 10-100 mL are possible and demonstration of log reductions to Class A standard is required. For produce with a protective peel, e.g. oranges, or produce not directly ingested without cooking, a lower standard of pathogen reduction will be acceptable. However, horticultural areas are usually mixed in nature, and it is unlikely that schemes would be viable without full Class A treatment processes. Data does not exist to suggest horticultural reuse schemes lead to a concentration of chemicals in produce. Therefore, in the absence of an indirect drinking water component to the scheme, there is no requirement to meet Department of Health chemical criteria for human consumption. For public acceptance and transparency, it is likely that chemical monitoring will be necessary to reassure the public of produce safety. Conclusion: The EPA supports in principle MAR to provide water for irrigated horticulture. Trials may be appropriate in some circumstances to demonstrate that water quality improvements would be achieved to meet Department of Health requirements, and that MAR will not result in unacceptable environmental impacts. MAR should not be viewed as a panacea to water shortages or an opportunity to increase abstraction, placing pressure on other environmental values.

MAR for Multiple Benefits There are multiple demands for groundwater at the western edge of the Gnangara Mound. These include horticultural irrigation, pine tree plantations, environmental needs, in the form of groundwater dependent ecosystems including wetlands and 33

caves, and public water supply needs drawn by the Water Corporation. It is likely that a MAR scheme could be devised that would have multiple benefits including maintenance of environmental needs. Groundwater modelling is currently in progress to determine the volume and location of recharge. It is likely that locations for recharge would be largely in the Carabooda or Pinjar regions, similar to those for horticultural irrigation and drinking water supplies, but would be able to provide benefits for the whole Gnangara groundwater resource. The EPA considers that the key environmental issues requiring further investigation prior to implementation of large-scale MAR scheme for multiple benefits are as cited for Irrigated Horticulture. Conclusion: As for MAR for irrigated horticulture, the EPA supports MAR for multiple benefits in principle. Trials may be appropriate in some circumstances to demonstrate that MAR will not result in unacceptable environmental impacts

MAR for Integrated Water Management in New Residential Areas MAR may be implemented in new residential areas as part of an integrated water management scheme. For example, around the proposed Alkimos and East Rockingham Wastewater Treatment Plants there is the potential to use MAR to recharge the aquifer with treated wastewater, which could be abstracted for backyard garden use or irrigation of public open spaces and golf courses. This is currently done in Salisbury, Adelaide at the Mawson Lakes development. The $16m recycling scheme treats a mixture of treated wastewater from the Bolivar Wastewater Treatment Plant and stormwater harvested in Salisbury to Class A standard. The treated wastewater is stored and extracted from deep saline aquifers (Gardner 2003). This is used in combination with a third pipe system (see Section 6), with the extracted water used for all outdoor purposes and toilet flushing. The Department of Health advise that the critical component of integrated schemes is the presence or absence of “in-house use”. All schemes connected to each residential property, even if for toilet flushing or bathroom use alone, must be treated to a Class A standard. The majority of previous reuse schemes involving in-house usage have at some stage been associated with cross-connection issues. Accordingly, when this possibility is factored in, quantitative microbial risk assessment modelling requires Class A pathogen log reductions. As the schemes described above for new residential areas do not include a component of drinking water reuse, the Department of Health do not require chemical monitoring. Schemes involving reuse for drinking water are covered below. Schemes which only involve open space irrigation or other external use may have lesser quality pathogen standards. Conclusion: The EPA supports in principle MAR using treated wastewater as a component of integrated water management in new residential areas. The consideration of any specific proposal will require detailed information if any significant environmental impacts are likely. The EPA also recommends consideration of third pipe systems, as discussed in Section 6.

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MAR to Increase Drinking Water Supplies As discussed in Section 3.1, MAR schemes to augment drinking water supplies currently exist in a number of locations around the world. The potential for MAR to increase drinking water supplies is also being investigated in further areas, including Pima County Arizona (Arizona Daily Star, 19 June 2005), and Toowoomba in Queensland (ABC News Online, 13 July 2005). The primary issue for use of MAR to increase drinking water supplies is protection of public health. Use of MAR for drinking water reuse raised the greatest number of concerns in public submissions and by attendees at the public forums, however, the majority of submitters/attendees, supported the concept of MAR for drinking water reuse. Extensive community consultation should occur before developing and implementing any such scheme. The Gnangara Mound is Perth’s primary source of groundwater for drinking water supplies. A reduction in rainfall for Perth since the mid 1970s has resulted in reduced natural recharge and declining water levels on the mound. MAR therefore provides a significant opportunity for offsetting the reduction in natural recharge to maintain or increase drinking water supplies from the Mound. The Water Corporation conceptually propose that treated wastewater from the Beenyup Wastewater Treatment Plant, following advanced tertiary treatement (with micro-filtration and reverse osmosis), could be used for MAR on Gnangara Mound. The wastewater could be recharged either by piping inland either for infiltration to the superficial aquifer, or by injection into the Leederville confined aquifer. Such a scheme would allow increased upstream abstraction of native groundwater, and the potential for later abstraction of the recharged water for public drinking water supplies. The recharge and abstraction points would be separated by several kilometres, and would therefore meet the Department of Health Recycled Water – Groundwater Recharge Guidelines requirement of, respectively, at least six or nine months retention time in the aquifer, following infiltration or injection. It is expected that the sequential purification provided by advanced tertiary treatment, the natural capacity of the aquifers to purify the water, along with dilution due to mixing with the native groundwater, would be signficant. With current flows from Beenyup WTW, up to 27 GL per year of tertiary treated effluent could be recharged, with an estimated 7 GL per year of secondary treated and RO reject wastewater discharged to the ocean through the existing ocean outfall. The Water Corporation Draft Position Statement ‘Public Drinking Water Source Areas and Aquifer Replenishment with Recycled Water’ states that any MAR proposal in a Public Drinking Water Source Area (PDWSA) would need to demonstrate no increase in risk to water quality (equating to the DoE management strategy for Priority 2 areas). Any MAR project in a Public Drinking Water Source Area (PDWSA) would require the Department of Environment approval. The provisions of the Gnangara Mound Crown Land Environmental Protection Policy also apply. The Department of Environment has confirmed that detailed scientific studies, trials and assessment of

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the social acceptability of indirect drinking water reuse of treated wastewater should be carried out to demonstrate its viability, prior to any large scale scheme. The trials should preferably be undertaken outside of operational PDWSAs. Depending on the site chosen for MAR, there may also be surface and underground ecosystems that would require protection. All MAR schemes which involve a component of indirect drinking water reuse would be required to comply with the full spectrum of Health Department Guidelines (Appendix 2) or subsequent revisions thereof. The Health Department also considers that trials should be undertaken outside of PDWSAs, particularly on the fate of chemicals, before any trial in a PDWSA. Conclusions: The EPA supports further investigation of MAR to increase drinking water supplies. In line with Department of Environment and Health Department advice, the EPA considers appropriate studies and trials should be undertaken outside PDWSAs. Any future proposal in a PDWSA would be assessed on its merits, including an assessment of risk, and be subject to full public review. The EPA supports the National Water Quality Management Strategy view (Government of Western Australia 2003c, 2004) that indirect drinking water reuse may in some cases be the best planning option for the management of the water cycle, where fresh water resources are limited.

6.

Other advice

The EPA recommends further investigation of third pipe systems for specific applications, particularly new developments. These are centralised schemes based on recycled water (obtained either from wastewater or stormwater) supplied to households. The schemes are known as third pipe, as scheme drinking water is supplied in the first pipe, wastewater leaves the house in the second pipe and recycled water is supplied through the third pipe connected to the residence. In some schemes the third pipe provides water only for outdoor use, while in other schemes this water is also used for toilet flushing. It is recognised that third pipe systems are expensive to install in already built urban areas. However the EPA considers that third pipe schemes using wastewater warrant consideration in new urban areas, particularly near proposed new wastewater treatment plants, such as East Rockingham and Alkimos. A number of third pipe systems exist in residential areas around Australia. These include Rouse Hill in New South Wales, New Haven in Adelaide and Springfield in Queensland. At Rouse Hill, for example, 4.4 ML/day of wastewater from the Rouse Hill wastewater treatment plant is treated for reuse by ozonation, microfiltration and superchlorination. This provides water to 12 000 homes using purple pipes (Australian Academy of Technological Sciences and Engineering 2004). The major issue associated with this scheme to date has been the number of plumbing errors in connecting Sydney Water mains to house fittings, leading to cross connections (Australian Academy of Technological Sciences and Engineering 2004).

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One of the key projects in Australia is the Pimpama Coomera WaterFuture Project in Queensland. This is a pilot study for exploring new methods of water management. This includes supply of water to houses from rainwater for bathrooms and laundries, recycled water for toilet flushing and external uses, and scheme drinking water for use in the kitchen. The project aims to reduce drinking water consumption by 84%, and use 86% of recycled water used from the new Pimpama Wastewater Treatment Plant (Gold Coast City Council 2004). The council also intends to investigate MAR as a means of water storage for times of low demand. The Department of Health advise that Class A water would be required for any third pipe system, along with stringent governance regarding the management and ongoing maintenance of any such proposals.

7.

Future Work

MAR is a developing technology in Australia (Scatena and Williamson 1999). It is the view of the EPA that further research, including trials, is required before any large scale MAR using treated wastewater can operate on the Swan Coastal Plain. It is considered that there is a reasonable level of knowledge of the health risks associated with MAR, and how gaps in this knowledge can be addressed (see Department of Health Draft Recycled Water – Groundwater Recharge Guidelines). With respect to environmental risks, the EPA recommends that the Department of Environment develop a strategy to address quantification of the environmental risks associated with MAR, and how any knowledge gaps can be addressed. Key issues identified by the EPA for further consideration include: ? the potential sustainability benefits of MAR; ? environmental risks and risks associated with chemicals in treated wastewater, such as endocrine disruptors, heavy metals, pharmaceuticals and nutrients. This should include modelling to predict environmental concentrations for assessment against predicted no effect concentrations. ? the behaviour of disinfection by-products, and potential for trihalomethanes to be formed; ? impacts of recharge water on chemical and microbiological characteristics of the native groundwater; ? the potential for chemicals in wastewater to bioaccumulate in the food chain (Department of Fisheries, 22 November 2004); ? the fate and survival of introduced micro-organisms in groundwater; ? the chemistry of MAR on the Swan Coastal Plain and the potential for the release of arsenic; ? aquifer composition under conditions of long-term recharge of wastewater, and ? social studies regarding community knowledge and acceptance of MAR. The EPA considers that it would be valuable to consolidate and consider together the results of all MAR trials to date. There is also the potential to gain data from existing operations, such as the Kwinana Wastewater Treatment Plant, regarding parameters such as pathogen die-off.

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Trials were identified by members of the public as an important stage in the public acceptance of MAR, and the EPA concurs with this view. The EPA also expects that trials would be valuable in the study of chemical and biological processes in the subsurface, and as a test of predictive transport modelling. The EPA notes that a collaborative research project (including the Department of Environment, Department of Health and Water Corporation) is proposed under the Premier’s Collaborative Research Program. This is planned as a three year project aimed at characterising treated wastewater for drinking, following reverse osmosis treatment. Wastewater would be characterised for its microbial and chemical constituents, and to understand any seasonal and catchment differences in trace contaminants of concern in relation to human and environmental health. One of the major project aims would be to determine the key chemicals of concern in Perth’s treated wastewater which need to be monitored and managed, and the effectiveness of best available high technology treatment processes to remove them. The Water Corporation has also begun a project with Oceanica and input from the Department of Environment, to assess the environmental risks of MAR using treated wastewater on the Gnangara Mound. The project is a first stage in characterising the risks associated with MAR on the Swan Coastal Plain and determining the level of wastewater quality improvement required to ensure an acceptable environmental outcome, as required by the Water Reuse Steering Committee. The environmental risk assessment work will define the process needed to address the environmental risks and impacts associated with the use of treated wastewater for groundwater recharge, and determine the process to address any information gaps that currently prevent risks from being quantified. The Department of Environment is developing a policy on MAR in the 2005-06 financial year. It is expected that this will address options for trading and/or cost recovery of MAR schemes. The Department of Environment are also developing a Water Quality Protection Note ‘Artificial Recharge of Groundwater’. This will provide the current views of the Department on MAR, and provide guidance on the issues of environmental concern. It is expected that this will be released in late 2005.

8.

Conclusions
1. That the Minister notes that this strategic advice is for managed aquifer recharge using treated wastewater on the Swan Coastal Plain; 2. That the Minister considers the report on the relevant factors as set out in Section 4; 3. That the Minister notes that the EPA supports in principle the concept of wastewater use and supports the investigation of MAR using treated wastewater as a means of water management on the Swan Coastal Plain. The EPA has provided a strategic framework in which the concept of MAR on the Swan Coastal Plain can be considered further.

The EPA submits the following recommendations to the Minister for the Environment:

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Appendix 1
References

Aertgeerts R and Andelakis A (Ed.) 2003, Health risks in aquifer recharge using reclaimed water - State of the art report, World Health Organization, Copenhagen, Denmark. Allison L et al. 2002, The value of water: Inquiry into Australia’s management of urban water. Report of the Senate Environment, Communications, Information Technology and Arts Reference Committee. http://www.aph.gov.au/senate/committee/ecita_ctte/completed_inquiries/200204/water/report/contents.htm Appleyard SJ, Angeloni J, Watkins R submitted, Arsenic contamination of groundwater due to an altered water balance in Perth, Western Australia: the effects of changing landuse and low rainfall over a thirty year period, Applied Geochemistry. Anderson J 2003, The environmental benefits of water recycling and reuse. Water Science and Technology: Water Supply. 3(4),1-10. Anderson J, Adin A, Crook J, Davis C, Hultquist R, Jimenez-Cisneros B, Kennedy W, Sheikh B, van der Merwe B 2001, Climbing the ladder: a step by step approach to international guidelines for water recycling. Water Science and Technology 43(10):18. ARMCANZ/ANZECC 1994, National Water Quality Management Strategy, Policies and Principles – a reference document. Agriculture and Resource Management Council of Australia and New Zealand and the Australian and New Zealand Environment and Conservation Council, Canberra, ACT. ARMCANZ/ANZECC 2000a, National Water Quality Management Strategy, Guidelines for Sewerage Systems, Use of reclaimed water. Agriculture and Resource Management Council of Australia and New Zealand, Australian and New Zealand Environment and Conservation Council, and National Health and Medical Research Council. ARMCANZ/ANZECC 2000b, Australian Guidelines for Water Quality Monitoring and Reporting, Agriculture and Resource Management Council of Australia and New Zealand, Australian and New Zealand Environment and Conservation Council, and National Health and Medical Research Council. ARMCANZ/ANZECC 2000c, Australian and New Zealand Guidelines for Fresh and Marine Water Quality, Agriculture and Resource Management Council of Australia and New Zealand, Australian and New Zealand Environment and Conservation Council, and National Health and Medical Research Council. ARMCANZ/ANZECC 1997 National Water Quality Management Strategy, Guidelines for Sewerage Systems, Effluent Management. Agriculture and Resource Management Council of Australia and New Zealand, Australian and New Zealand Environment and Conservation Council, and National Health and Medical Research Council.

Australian Academy of Technological Sciences and Engineering 2004, Water Recycling in Australia, Victoria, Australia. Australian Groundwater Technologies 2004, Mosman reclaimed water prefeasibility study, Australian Groundwater Technologies. Australian Water Resources Council (1982) Guidelines for the Use of Reclaimed Water for Aquifer Recharge. Water Management Series No. 2. Australian Government Publishing Service, Canberra. Berti ML, Bari MA, Charles SP, Hauck EJ 2004, Climate Change, Catchment Runoff and Risks to Water Supply in the South-West of Western Australia, Department of Environment, Government of Western Australia. Centre for Groundwater Studies 1999, A potential role for artificial recharge in the Perth Region: A pre-feasibility study. Centre for Groundwater Studies Report No. 84. Chapman H 2003, Removal of endocrine disruptors by tertiary treatments and constructed wetlands in subtropical Australia. Water Science and Technology 47(9), 151-156. Department of Environmental Protection 1996, Southern Metropolitan Coastal Waters Study (1991 – 1994), Final Report. Department of Environmental Protection, Perth Western Australia, November 1996. Department of Water, Land and Biodiversity Conservation South Australia, 2005 http://www.dwlbc.sa.gov.au/water/groundwater/capabilities/asr.html. Dillon P (Ed) 2000, Management of Aquifer Recharge for Sustainability. Proceedings of the 4th International Symposium on Artificial Recharge of Groundwater, ISAR-4, Adelaide, South Australia 22-26 September 2002. A.A. Balkema Publishers for Swets and Zeitlinger B.V., The Netherlands. Dillon P and Pavelic P 1998, Guidelines on the quality of stormwater and treated wastewater for injection into aquifers for storage and re-use, Urban Water Research Association of Australia Research Report No. 109. Edmonds LW, Rule H, Cadee K 1987, Canning Vale Groundwater Recharge Study, pp8. Published by Internal Report of Water Authority of Western Australia. EPA (1990). Albany Harbours Environmental Study 1988 – 1989: Bulletin 412, A report to the from the Technical Advisory Group. Environmental Protection Authority, Perth, Western Australia, February 1990. Environmental Protection Authority 2000, Perth’s Coastal Waters, Environmental Objectives and Values. Perth, Western Australia. Environmental Protection Authority 2003, Consideration of Subterranean Fauna in Groundwater and Caves during Environmental Impact Assessment in Western

Australia. Guidance for the Assessment of Environmental Factors No. 54. Perth, Western Australia. Environmental Protection Authority 2004, Principles of Environmental Protection, Position Statement No. 7. Perth, Western Australia. Environmental Protection Authority 2005, Managed Aquifer Recharge using Treated Wastewater on the Swan Coastal Plain, A Discussion Paper. Perth, Western Australia Falconer IR, Moore MR, Chapman HF and Ranmuthugala G 2003, Endocrine Disruptors in the Context of Australian Drinking Water. Occasional Paper Number 7. CRC for Water Quality and Treatment, Adelaide, Australia. ISBN 1876616229 Fram M, Bergamaschi BA, Goodwin KD, Fujii R, Clark JF 2003, Processes Affecting the Trihalomethane Concentrations Associated with the Third Injection, Storage, and Recovery Test at Lancaster, Antelope Valley, California, March 1998 through April 1999, U.S. Geological Survey, Water–Resources Investigations Report 03-4062, Sacramento, California 2003 Gardner, EA 2003, Some examples of water recycling in Australian urban environments: a step towards environmental sustainability. Water Science and Technology 3(4), 21-31. Gold Coast City Council (2004) Pimpama Coomera WaterFuture – WaterFuture Master Plan, http://www.goldcoast.qld.gov.au Government of Western Australia 2003a, A State Water Strategy for Western Australia. Perth, Western Australia. Government of Western Australia 2003b, Hope for the Future: The Western Australian State Sustainability Strategy, Department of the Premier and Cabinet. Perth, Western Australia. Government of Western Australia 2003c, State Water Quality Management Strategy. Implementation Plan: Status Report. Perth, Western Australia. Government of Western Australia (2004). State Water Quality Management Strategy Document No. 6. Implementation framework for Western Australia for the Australian and New Zealand Guidelines for Fresh and Marine Water Quality Monitoring and Reporting (Guidelines Nos 4 & 7: national Water Quality management Strategy). Government of Western Australia, 2004. Icekson-Tal N, Avraham O, Sack J and Cikurel H 2003, Water re-use in Israel – the Dan Region Project: Evaluation of water quality and reliability of plant’s operation, Water Science and Technology: Water Supply. 3(4), 231-237. National Health and Medical Research Council and Natural Resource Management Ministerial Council 2004, Australian Drinking Water Guidelines.

Parsons Brinckerhoff 2005, Goulburn Water Reclamation Scheme, Goulburn City Council. Pavelic P, Nicholson BC, Dillon PJ, Barry KE 2005, Fate of disinfection by-products in groundwater during aquifer storage and recovery with reclaimed water, Journal of Contaminant Hydrology 77:119-141. Pescod MB 1992, Wastewater treatment and use in agriculture – FAO Irrigation and Drainage Paper 47, Food and Agriculture Organization of the United Nations, Rome. Po M, Nancarrow BE, Leviston Z, Porter NB, Syme GJ, Kaercher JD 2005, Predicting Community Behaviour in Relation to Wastewater Reuse: What drives decisions to accept or reject? Water for a Healthy Country Research Flagship. CSIRO Land and Water: Perth, Australia Post Newspaper, 2004 (7 February 2004 and 26 June 2004) Tough choices loom over bore water. http://www.postnewspapers.com.au/ Prime Minister’s Science, Engineering and Innovation Council 2003 Recycling Water for Our Cities, Australia. Pyne, RDG, Groundwater Recharge and Wells: A Guide to Aquifer Storage Recovery. Lewis Publishers, 1995. Queensland Environmental Protection Agency 2004, WaterWise Queensland - Public consultation draft - Queensland Guidelines for the Safe Use of Recycled Water. Resource Sciences and Knowledge (2000) Groundwater Recharge Background Study, Queensland Water Recycling Strategy, Queensland, Australia. Revenga C, Brunner J, Henninger N, Payne R, and Kassem K 2000, Pilot Analysis of Global Ecosystems (PAGE): Freshwater systems, World Resources Institute, United States of America. Scatena MC and Williamson DR 1999, A Potential Role for Artificial Recharge in the Perth Region: A pre-feasibility study, Centre for Groundwater Studies Report Number 84. Perth, Western Australia. SKM 1996, Mosman Park re-use – feasibility study. Feasibility report to WA Water Corporation and Town of Mosman (draft). Southwest Consortium for Environmental Policy and Research 1999, SCERP Project Number: W14, http://www.scerp.org/projects/W14.html Swan River Trust 1999, Swan Canning Cleanup Program. Swan River Trust, Perth, Western Australia. http://www.wrc.wa.gov.au/srt/sccp/html/menu.html Tchobanoglous G and Burton FL 1991, Wastewater Engineering: Treatment, Disposal and Reuse, Third Edition, Metcalf & Eddy, Inc. 1991.

Toowoomba City Council 2005, Water Futures – Toowoomba: Taking Control of Toowooomba’s Future, Briefing Paper. Toze S 2004, Reuse of effluent water – benefits and risks, “New Directions for a Diverse Planet”, Proceedings of the 4th International Crop Science Congress, 26 Sep – 1 Oct 2004, Brisbane, Australia. Toze S, Dillon P, Pavelic P, Nicholson B, Gibert M 2001, Aquifer storage and recovery: removal of contaminant from stored waters, 10th Biennial Symposium on the Artificial Recharge of Groundwater, Tuscon, Arizona, June 2001. Toze S, Hanna J, Smith A, Hick W 2002, Halls Head Indirect Treated Wastewater Reuse Scheme, A Report to Water Corporation, Western Australia, October 2002. Toze S, Hanna J, Smith T, Edmonds L, McCrow A 2004, Determination of water quality improvements due to the artificial recharge of treated effluent, Wastewater Reuse and Groundwater Quality (Proceedings of symposium HS04 held during IUGG2003 at Sapporo, July 2003). IAHS Publ. 285. United Nations Environment Programme 2000, International Source Book On Environmentally Sound Technologies for Wastewater and Stormwater Management, United Nations Environment Programme, Osaka. Victoria Environmental Protection Authority 2003, Guidelines for Environmental Management Use of Reclaimed Water, EPA Victoria http://epanote2.epa.vic.gov.au/EPA/Publications.nsf/0/64c2a15969d75e184a2569a00 025de63/$FILE/464.2.pdf Vogwill, RIJ 2004, Sensitivity of the Water Table in the Perth Region to Changes in Climate, Landuse and Groundwater Abstraction using the PRAMS model, Department of Environment, Western Australia, HR 223. Warner F 1992, Introduction – Risk Analysis, Perception, Management. Report of the Royal Society Study Group, The Royal Society, London. Water Corporation 2002, Reclaimed water, Presentation by the Water Corporation at the Community Water Forum. http://www.ourwaterfuture.com.au/community/pres_wastewater_re-use.pdf Subiaco, Western Australia. Water Corporation 2005, Integrated Water Supply Scheme Source Development Plan, Planning Horizon 2005-2050 http://www.watercorporation.com.au/publications/22/SourcePlan_2005.pdf Water and Rivers Commission 2000, Western Australia Water Assessment 2000. Water Availability and Use. Water and Rivers Commission. Perth, Australia. Water and Rivers Commission 2002, Draft State Water Conservation Strategy for Western Australia, Water and Rivers Commission and Office of Water Regulation. Perth, Australia.

Appendix 2

Draft Department of Health Guidelines

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Recycled Water Groundwater Recharge Guidelines

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Recycled Water Groundwater Recharge Guidelines

Table of Contents

2

Principles Underpinning Health Guidelines Water Quality Objectives Pathogens Heavy Metals Chemicals Radiation Minimum Treatment Processes Monitoring Requirements, including testing wells Source Control Program Recharge methods, retention times and distance to extraction Engineering Report Operations and Maintenance Manual Appendix A Appendix B Appendix C

3 4 4 5 5 7 7 8 8 9 9 10 11 14 19

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Principles Underpinning Health Guidelines
A number of principles underpin the derivation of health guidelines for aquifer recharge settings and these must be addressed in any proposal. They are: 1. All schemes must be individually approved although new users may be added to a scheme if the proposed new use is of an equivalent or lesser human exposure level.. 2. All schemes must adopt a risk management framework. 3. All schemes are approved on a “fit for purpose” basis. The allocation of any proposed scheme to a “fit for purpose” category is based on the extent of human exposure and the subsequent modeled risk. For example, all aquifer recharge schemes involving indirect potable use are assumed to have an ingestion exposure of two litres per day for 70 years. 4. Requirements will include both quality and process components 5. All schemes require three types of monitoring. 5.1. Validation (will it work): this may include chemical and pathogen testing to demonstrate effectiveness of removal processes however surrogates can be used to demonstrate this (eg MS2 phage)1. Validation testing is based on obtaining a sufficient database to provide convincing evidence that a process or method will work. 5.2. Operational Testing (is it working): this will include a series of measurements and observations to confirm performance of preventative measures. Operational monitoring is based on the need to allow timely intervention and can be both continuous (disinfection, filtered water turbidity) or six monthly (inspection of structures). 5.3. Verification (did it work): this may include testing for chemicals and microorganisms. The frequency of required monitoring is based on an assessment of need, and is based on notional ideas about the variability of water quality characteristics system complexity and other perceptions. 6. The water extracted from the aquifer after the recharge process must be of a required quality without extra treatment being necessitated. 7. While a risk management approach is required for all aquifer recharge proposals, for those involving indirect potable reuse, the best available technology is also mandated and must include a reverse osmosis component.

MS2 phage is a bacteriophage or a virus that infects bacteria. These bacteriophages are easier to grow and propagate than viruses which infect man and are used to test how other viruses would act when these viruses can’t be examined directly. MS2 phage, a single stranded RNA virus, has been used in many water reuse schemes to monitor how, more difficult to assess, human viruses of concern would be affected.

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8. The major health issues of concern are chemicals and pathogens, including viruses, bacteria, helminths, and parasites. Overseas work has demonstrated the relative unimportance of heavy metals and radiation although local validation of this will be required. 9. Separation times will be required between recharge and extraction for all proposals involving indirect potable re-use. Minimum times based on the mode of recharge will be identified. These will be shorter for infiltration compared to injection but, in all cases, the longer the time between recharge and extraction, the greater the margin of safety. Minimum separation distances between infiltration or injection and extraction will also be required. Separation times will also be required for class A schemes such as horticulture, if these have been approved without a requirement for full treatment prior to spreading.

WATER QUALITY OBJECTIVES
Pathogen Improvement Requirements There has been significant recent debate about the acceptable level of pathogen reduction which should be mandated for water quality. Various models of quantitative microbial risk assessment (QMRA) have been assessed. The most recent consensus approach appears to be to set a health modeling limit of 1 x 10-6 Disability adjusted life years (DALYS) to allow for both the risk of infection and the potential severity of infection as well. The required log removal numbers using this approach equate quite closely to those derived from modeling a 1 in 10-3 infection risk. In the derivation of the required level of disinfection or log removal, the most important factor is the concentration of pathogens in the source material so direct pathogen monitoring of sewerage may be required to undertake the risk assessment. In a DALY model, viruses remain the most important pathogen in terms of probability of exposure as generally they lead to more severe outcomes of infection. To satisfy viral log removal QMRA criteria however would require demonstration of very low concentrations of viruses eg. one per 10,000 litres and this is beyond the capacity of current laboratory processes. In view of this, aquifer recharge proponents will need to demonstrate: ? Validation of their proposed process. For example, class A or indirect potable schemes utilizing treated wastewater will need to demonstrate a 7 log pathogen reduction in influent or demonstrate a 5 log removal after the secondary treatment stage. This validation must cover the full range of pathogens although indicator organisms such as MS2 phage can be substituted for direct viral testing. The required extent of validation processes will be decreased if the process proposed is based on systems with known pathogen removal rates such as a standardised Title 22 system. A HACCP type framework with corrective actions for potential problems. This framework should incorporate a scheme specific operational testing regime with parameters such as turbidity, UV light dose, chlorine residual etc relevant to the proposal.

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?

A verification model based on pathogen testing.

The required standard of microbiological water quality for varying reuse schemes including MAR is shown in Appendix A. (Page 11) The expected microbiological effectiveness of treatment trains, on site controls and possible suitable uses currently under consideration in the proposed national reuse guidelines are shown in Appendix B. (Page 14) Heavy Metals International and interstate data suggest that the combination of source control programs and standard wastewater treatment processes eliminate heavy metals as a health risk in reuse projects. Monitoring of post treatment effluent has invariably identified heavy metal concentrations of 1 to 2 orders of magnitude below current drinking water guidelines. In view of this, proponents will be required to submit a single set of data confirming the absence of heavy metals and no further monitoring will be required. Chemicals An extensive assessment of potential chemical impacts is required for indirect potable schemes and the information gleaned from this assessment must be fed into source control programs where relevant. Proponents will need to undertake a review of the following groups, however much of this is for scheme assessment and not all agents will have action levels or required responses: ? ? ? ? Chemicals with known maximum contaminant levels as identified in the current drinking water guidelines. Chemicals without known MCLs but for whom an action level exists. Priority toxic pollutants as determined by the Department of Health. Endocrine disrupting chemicals, pharmaceutically active compounds and other chemicals. In this group required assessments will include: o some synthetic and natural hormones such as ethinyl oestradiol, 17-B oestradiol and oestrone; o a range of industrial endocrine disruptors including bisphenolA, nonylphenol and nonylphenol polyethoxylate, octylphenol and octylphenol polyethoxylate, and polybrominated diphenylethers; Phthalates are not on the list of required monitoring chemicals as epidemiological evidence suggests it is unnecessary.

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While EDC monitoring will be required, it is as much for public transparency as for any health risk assessment. Recent Queensland work using mosquito fish (Gambusia) demonstrated no intersex or shortening of the male fin in recycled water. Additionally, concentrations of endocrine disruptors required to affect fish were higher than those found naturally in the wetlands post secondary treatments from wastewater treatment plants. In addition, toxicological effects were possible at levels lower than those required to cause endocrine effects. Other non reuse sources of endocrine disrupting compounds are ubiquitous and the relative risk for human health from recycled water remains negligible. Research is continuing and will be monitored however, at this point of time, endocrine disrupting compounds are regarded not as a health issue but are an environmental and public perception issue. ? ? Other priority pharmaceuticals which are not endocrine disruptors will also need to be measured. Tentatively identified or “yet to be imagined” Chemicals. Considerable debate has occurred regarding the public perception requirement to demonstrate the absence of any possible harm from currently identified compounds at levels below detection or compounds outside the range of normal review. Some overseas regulators have managed this process by requiring mass spectrographic reviews of wastewater looking for tentatively identified compounds which would then require further investigation, and also by setting a total organic carbon (TOC) limit on individual schemes to ensure that oxidative removal processes were sufficient to deal with all organics. These overseas guidelines currently include a requirement to reduce TOC to a level of 1mg/L litre. With spreading schemes it is allowable for the required TOC levels to be achieved in mound monitoring in the vadose zone and not to be required in the spreading water itself. These strict TOC requirements also only apply to intentional ground water recharge for reuse municipal water supplies and are not required in a number of other recharge settings. In Western Australia a program to look for tentatively identified compounds may not be a requirement for operational reuse schemes but the possible benefit of this program will be assessed in aquifer recharge trials over the next few years. Similarly a decision on the benefits of such tight TOC requirements will be made after recharge trials. Overseas schemes have also set limits on total nitrogen levels at 5mg/L. These levels were set due to concerns over potential increases in total nitrogen fixation in the aquifer and concerns that subsequent nitrite/nitrate levels in drinking water may exceed guidelines. Data are not however available to support the concerns that fixation is occurring. In addition recent reviews of the real health importance of nitrates in drinking water have tended to the view that only met-haemaglobinaemia is important and that even the importance of this as a neonatal concern has been greatly overstated leading to overly restrictive nitrate guidelines. These recent data will be considered when a final decision is made on total nitrogen in reuse schemes.

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?

At this point in time, public health guidelines are focused on protection via mandated process trains, and the collection of further information during recharge trials in Western Australia. Data from monitoring wells in trials will heavily influence final decisions.

The list of chemicals required to be monitored in Western Australia for any indirect potable scheme associated with MAR is attached in Appendix C. (Page 17) This overly-exhaustive list forms the basis of discussions for reuse monitoring during reuse and MAR trials. The Department of Health anticipates reducing the list after demonstration of effective chemical reduction processes during upcoming trials. A number of lists exist to set investigation and intervention levels for chemicals of concern. These include the Californian wastewater reuse guidelines, the Australian Drinking Water Guidelines and the European Union predicted no effect levels (PNEC). This information, along with the results of chemical testing during reuse trials, will be used to set levels for action (divert scheme water), levels for notification (look at what is happening), and levels of interest (collect information until we understand more) in the final WA Health indirect potable guideline. Radiation Current Western Australian drinking water guidelines for testing radiation reflect significant background levels in some sources and testing difficulties. Rather than the full suite of ADWG testing water authorities are only required to test for radium sources and not for total alpha or beta levels. Reuse schemes will require a source control program which may identify industrial sources and the need for extra testing. Overseas work however, suggests that generic potential sources of radiation, such as the excretion of sources in the urine post radiation therapy, are unimportant due to the small number of affected individuals, the associated dilution and the short half life of isotopes involved. Reuse schemes will only be required to meet current radium testing guidelines applicable to drinking water. However the issue has been referred to the West Australian Radiological Council and guidelines may be altered if the councils’ deliberations require this, or if source control reviews identify concerns.

Minimum Treatment Processes
The required minimum treatment processes include validating systems to comply with the requirements of pathogen log reduction and to comply with requirements for chemical removal described previously. Current consensus is that some aquifers provide minimal control over chemical removal so all Western Australian aquifer recharge schemes involving indirect potable reuse will require a reverse osmosis step within the treatment process. Reverse osmosis is a proven technology for chemical removal and while some data exist that nano-filtration technology may be a viable option, nano-filtration is a less well proven technology and is not deemed acceptable at this point of time.

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Monitoring Requirements including testing wells
The requirement for validation, operational monitoring and verification were outlined in the principles underpinning scheme approvals. Validation for aquifer recharge schemes will include weekly demonstration of pathogen reduction in all 4 pathogen groups for at least 2 months prior to commissioning of schemes. This pre-commissioning phase may be increased if expected log reductions are not met or ‘innovative technology’ is used to achieve the pathogen reductions. Validation will also include continuous monitoring of key operational conditions relevant to the plant construction eg turbidity, conductivity, chlorine residual … These parameters will form the basis of operational monitoring subsequently. In addition precommisioning will also involve quarterly review of chemical levels for the priority list as determined by the Department of Health, an assessment of TOC levels and some mass spectrographic analysis. Interim monitoring wells will be required for all schemes. These wells will be used to: ? ? ? Confirm retention times between spreading / injection and extraction zones via tracer studies Monitor changes in chemical levels with time in the aquifer Confirm the absence of microbial contamination

A final specific determination of the extent of monitoring required will be made by the Department of Health in consultation with proponents after assessent of each individual scheme and the risks to human health.

Source Control Program
A source control program must be implemented and should include: 1. An assessment of the fate of the specified contaminant compounds through the wastewater and recycled water treatment systems. 2. A source investigation and monitoring program focused on the specified contaminants. 3. An outreach program to industrial, commercial and residential communities within the sewage collection agency’s service area to manage and minimize the discharge of compounds of concern at the source. 4. A program for maintaining an inventory of compounds discharged into the wastewater collection system so that the new compounds of concern can be evaluated rapidly. Overseas studies have shown that these source control programs can aid community input to and acceptance of reuse schemes.

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Recharge methods, retention times and distance to extraction
Proposals should include an overview of the proposed recharge methods whether injection or via spreading grounds and an estimate of the retention time and an outline of distance to extraction point. Precommisioning monitoring will be required to confirm estimates. As a general rule spreading systems will require retention times in the aquifer of at least six months and a notional separation of 150m between spreading and extraction with the retention time critical. Injection proposals will require retention times in the aquifer of at least nine months and a notional separation of 600m between injection and extraction

Engineering Report
All proponents shall submit an engineering report that includes an operations plan to the Department of Health. This report shall be prepared by an engineer experienced in the fields of wastewater treatment and public water supply, in conjunction with a geologist experienced in hydrogeology. Recycled water shall not be spread or injected until a complete engineering report is submitted and the Department of Health has issued an approval for precommisioning work to begin. The engineering report shall consist of a comprehensive investigation and evaluation of the project, impacts on the existing and potential uses of the impacted groundwater basin, and the proposed means for achieving compliance with the water quality criteria. The engineering report shall include, but not be limited to, the following: ? ? ? A description of the proposal; An engineering plan of the recycling plant, transmission facilities, spreading basins/subsurface injection bores, and monitoring bores; A hydrogeologic study on the impacted groundwater basin that addresses the following: Impact of the proposal on domestic groundwater sources; Description of any other existing or proposed projects that could impact the groundwater basin, and an estimate of the cumulative impact on water quantity and quality with and without the proposed project; Sources of groundwater basin recharge water, areas of surface spreading or subsurface injection, groundwater quantity, quality, and flow patterns for all aquifers in all impacted groundwater basins; For new projects, a description of the pre-project groundwater quality in the impacted groundwater basin; For all bores that will be impacted by the proposed project:

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? ? ?

?

? Use of each; ? The estimated or measured shortest recycled water retention time underground and horizontal separation, along with the methods for obtaining these; Quantitative descriptions of the aquifer transmissivity, groundwater movement, historic depth-to-groundwater, safe yield of the basin, influence of localized pumping, and usable storage capacity of the groundwater basin; and Description of any existing or anticipated flows into, or recharges of, the basin that could affect the quality of water in the monitoring bores or drinking water bores downgradient of the project. Identification of the agency responsible for preventing the use of groundwater for drinking water within certain areas, and the mechanism that will be used; A contingency plan for diversion of recycled water when required; A plan for monitoring groundwater flow and water quality in the impacted groundwater basin, including a map of the locations of monitoring bores in the spreading basin and groundwater basin, details on their construction, and a rationale for their siting; A water quality monitoring plan for the recycled water, diluent water, water in the vadose zone as necessary, water in the mound as necessary and monitoring bores;

Operations and Maintenance Manual
The operations and maintenance manual shall include, but not be limited to, the following: ? ? ? ? ? ? ? ? ? Operational and management personnel job descriptions and required qualifications and associated training programs; If RO membrane technology is used, the routine testing procedures for the integrity of the RO membranes and the RO membrane replacement schedule; Routine maintenance and performance monitoring for the disinfection system; Maintenance and calibration schedules for all monitoring equipment, process alarm set points and response procedures for all alarms; Maintenance of injection and monitoring bores, and spreading basins; Vector control activities related to the project; A description of how the project will measure the retention time to demonstrate compliance with required retention times. A list of the pesticides and herbicides used in the spreading facilities; and The procedures used for compliance with control of non regulated chemicals .

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Appendix A

Fit for Purpose microbiological guidelines for wastewater reuse

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Fit for Purpose Guidelines for Recycled Water *
Class Recycled Water Quality Objectives1 Turbidity < 2 NTU6 < 10 / 5 mg/L BOD / SS pH 6 – 9 7 1 mg/L Cl2 residual (or equivalent disinfection)8 <1 E.coli per 100 mL; <1 helminth per litre; < 1 protozoa per 50 litres; < 1 virus per 50 litres. <2-10mg/L nitrogen Meet DOH Chemical Guidelines for Recycled Water < 10 E.coli org/100 mL Turbidity < 2 NTU6 < 10 / 5 mg/L BOD / SS pH 6 – 9 7 1 mg/L Cl2 residual (or equivalent disinfection)8 <10 E.coli per 100 mL; <1 helminth per litre; < 1 protozoa per 50 litres; < 1 virus per 50 litres. B <100 E.coli org/100 mL pH 6 – 97 < 20 / 30 mg/L BOD / SS10 Secondary2 and pathogen reduction9 Treatment Process2 Range of Uses

A+

Secondary2 Filtration3 Disinfection4 Advanced treatment5

Indirect Potable Reuse Aquifer Recharge

A

Secondary2 Filtration3 Disinfection4

Urban (non-potable): with uncontrolled public access Agricultural: eg human food crops consumed raw Industrial: open systems with worker exposure potential Agricultural: eg dairy cattle grazing Industrial: eg washdown water Urban (non-potable): with controlled public access Agricultural: eg human food crops cooked/processed, grazing/fodder for livestock Industrial: systems with no potential worker exposure Agricultural: non-food crops including instant turf, woodlots, flowers

C

<1000 E.coli org/100 mL pH 6 – 97 < 20 / 30 mg/L BOD / SS10

Secondary2 and pathogen reduction9

D

<10000 E.coli org/100 mL pH 6 – 97 < 20 / 30 mg/L BOD / SS10

Secondary2

* Table adapted from Victorian EPA guidelines
1. 2. Unless otherwise noted, recommended quality limits apply to the recycled water at the point of discharge from the WWTP Secondary Treatment processes include activated sludge processes, trickling filters, rotating biological contractors, and may include stabilization ponds. Filtration means the passing of wastewater through natural undisturbed soils or filter media such as sand and/or anthracite, filter cloth, or the passing of wastewater through micro-filters or other membrane processes. Disinfection means the destruction, inactivation, or removal or pathogenic microorganisms by chemical, physical, or biological means.

3.

4.

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5.

Advanced wastewater treatment processes include chemical clarification, carbon adsorption, reverse osmosis and other membrane processes, air stripping, ultrafiltration, and ion exchange. Turbidity limit is a 24-hour median value measured pre-disinfection. The maximum value is five NTU. pH range is 90th percentile. A higher upper pH limit for lagoon-based systems with algal growth may be appropriate, provided it will not be detrimental to receiving soils and disinfection efficacy is maintained. Chlorine residual limit of greater than one milligram per litre after 30 minutes (or equivalent pathogen reduction level) is suggested where there is a significant risk of human contact or where recycled water will be within distribution systems for prolonged periods. Helminth reduction is either detention in a pondage system for greater than or equal to 30 days, or by a DOH approved disinfection system (for example, sand or membrane filtration). Where Class C or D is via treatment lagoons, although design limits of 20 milligrams per litre BOD and 30 milligrams per litre SS apply, only BOD is used for ongoing confirmation of plant performance. A correlation between process performance and BOD / filtered BOD should be established and in the event of an algal bloom, the filtered BOD should be less than 20 milligrams per litre.

6. 7.

8.

9.

10.

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Appendix B

Microbiological Effectiveness of treatment trains, on site controls and suitable uses

Draft national health reuse guidelines

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Typical treatment processes and specific on-site controls for designated uses
Use Treatment Process Total Log reduction required Description Log reduction
prot;virus; bact prot virus bact

On site control/use restrictions
Description Log reduction

Dual reticulation Municipal irrigation Municipal irrigation

5;

6;

5

3.5; 5;

4

3.5;

5;

4

Coagulation1 Filtration, Disinfection Coagulation2 Filtration, Disinfection Secondary Disinfection Secondary treatment with lagoons and disinfection

5;

6;

>6

5

5

>6

0.5-1 1-3 >6 Combinations of No public access 2-6 >6 during irrigation Possible exclusion periods (eg no use until 1-4 hrs after irrigation) 25-30m buffer zones to nearest point of public access Spray drift control: - low throw sprinklers - microsprinklers - part circle sprinkers (180O inward throw) - tree/shrub screens - amemoter switching No public access during irrigation and Possible exclusion periods (eg no use until 1-4 hrs after irrigation) and 25-30m buffer zones to nearest point of public access and Spray drift control: - low throw sprinklers - microsprinklers - part circle sprinklers (180O inward throw) - tree/shrub screens - amemoter switching Combinations of Microspray Drip irrigation No public access 2 log

1-4

1 log

1 log

1 log

Municipal irrigation

3.5; 5;

4

Secondary

0.5-1; 0-2; 1-3

2 log

1 log

1 log

1 log

Landscape irrigation

3.5; 5;

4

Secondary Disinfection Secondary

0.5-1; 1-3; >6

2 log 2 log 2 log

0.5-1; 0-2; 1-3

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Use

Treatment Process Total Log reduction required Description Log reduction
prot;virus; bact prot virus bact

On site control/use restrictions
Description Log reduction

Commercial food crop

5; 6; 5

Coagulation2 Filtration, Disinfection

5;

5; >6

1.5-2 days between final watering, supply and consumption Ground contact and eaten raw (eg lettuce, celery) or grown below surface and eaten raw (eg carrots) No ground contact and eaten raw (eg tomatoes, capsicums).

1 log (virus)

Commercial food crop

5;

6; 5

Secondary treatment with lagoons and disinfection

1-4; 2-6; >6

No ground contact (trees etc) and eaten raw (eg apples, peaches, apricots Drip irrigation 3 log No ground contact and eaten raw (eg tomatoes, capsicums). Spray irrigation Ground contact and skin removed prior to consumption (eg melons)2 and 1.5-2 days between final watering, supply and consumption

2 log

1 log (virus) 3 log

Commercial food crop

5;

6;

5

Secondary treatment and disinfection

0.5-1; 1-3; >6

Spray irrigation No ground contact and skin removed prior to consumption (eg citrus, nuts)2 and 1.5-2 days between final watering, supply and consumption

1 log (virus)

Commercial food crop

5;

6;

5

Secondary

0.5-1; 0-2; 1-3

Drip irrigation 4 log No ground contact (trees etc) and eaten raw (eg apples, peaches, apricots)3. Grown below surface and cooked or processed 5 log (eg potatoes, beetroot) No ground contact and heavily processed (eg grapes for wine production, cereal crops) Drip irrigation No ground contact and skin removed prior to consumption (eg citrus, nuts)2. 5 log

5 log

Commercial crop
1 3

Primary plus lagoons or secondary

0.5-1; 0-2; 1-3

Crop/plants not for human consumption (eg treelots, turf)

5-6 log

After secondary treatment, additional Ct set to achieve higher virus removal, 2 After secondary treatment, Produce not to be wet when harvested and dropped produce not to be harvested, 4 .Dropped produce not to be harvested

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Suitable uses associated with typical treatment processes and on-site controls
Treatment
Secondary Treatment Coagulation Filtration, Disinfection

Suitable Uses
Dual reticulation Municipal irrigation Commercial food crops (raw produce) Firefighting Industrial uses

On Site Controls

Water quality requirements
Turbidity ≤ 2 NTU Chlorine residual to achieve minimum Ct (could vary depending on use eg ≥ 60 mg.min/L for dual reticulation but lower for industrial uses) E.coli <1 per 100 mL for dual reticulation E.coli <10 per 100 mL for other uses BOD <20mg/L (as a measure of effectiveness of secondary treatment Chlorine residual to achieve minimum Ct (eg ≥ 15 mg.min/L) E.coli <100 per 100 mL

Secondary treatment Commercial food crops with lagoons and No ground contact and eaten raw disinfection (eg tomatoes, capsicums). Ground contact and skin removed prior to consumption (eg melons)2

Drip irrigation

Minimum 1.5-2 days between final watering, supply and consumption

Minimum detention in lagoons of 30 days BOD <20mg/L, SS < 30mg/L (as a measure of effectiveness of secondary treatment) Chlorine residual to achieve minimum Ct (eg ≥ 15 mg.min/L) E.coli <100 per 100 mL BOD <20mg/L, SS < 30mg/L (as a measure of effectiveness of secondary treatment) Chlorine residual to achieve minimum Ct (eg ≥ 15 mg.min/L) E.coli <100 per 100 mL BOD <20mg/L, SS < 30mg/L (as a measure of effectiveness of secondary treatment)

Secondary treatment Commercial food crops with disinfection No ground contact and skin removed prior to consumption (eg citrus, nuts)2 No ground contact (trees etc) and eaten raw (eg apples, peaches, apricots)3. Secondary treatment Municipal irrigation including with disinfection dust suppression

Spray irrigation and minimum 1.5-2 days between final watering, supply and consumption Drip irrigation Combinations of No public access during irrigation Possible exclusion periods (eg no use until 1-4 hrs after irrigation) 25-30m buffer zones to nearest point of public access Spray drift control: - low throw sprinklers - microsprinklers - part circle sprinklers (180O inward throw)

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Treatment

Suitable Uses

On Site Controls
- tree/shrub screens - amemoter switching

Water quality requirements

Landscape irrigation

Combinations of Microspray

Chlorine residual to achieve minimum Ct (eg ≥ 15 mg.min/L) E.coli <100 per 100 mL

Drip irrigation No public access during irrigation Secondary treatment Commercial food crops without disinfection Grown below surface and cooked or processed (eg potatoes, beetroot) No ground contact and heavily processed (eg grapes for wine production, cereal crops) No ground contact and skin removed prior to consumption (eg citrus, nuts)2. Landscape irrigation BOD <20mg/L, SS < 30mg/L (as a measure of effectiveness of secondary treatment) E.coli <1000 per 100 mL BOD <20mg/L, SS < 30mg/L (as a measure of effectiveness of secondary treatment)

Drip irrigation Combinations of Microspray Drip irrigation No public access during irrigation E.coli <1000 per 100 mL BOD <20mg/L, SS < 30mg/L (as a measure of effectiveness of secondary treatment)

Primary treatment with lagoons

Crop/plants not for human consumption (eg treelots, turf)

E.coli <10000 per 100 mL

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Appendix C

Initial list of priority “Chemicals of concern” for review prior to MAR projects involving indirect potable reuse. *

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* While a finalised list will only apply to schemes involving indirect potable reuse, it is likely that early MAR schemes, not involving a potable outcome, will be required to monitor these to provide baseline data.

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Chemicals of Concern in Recycled Water
VOCs2 Benzene Butyl benzenes - n-butyl benzene - sec-butyl benzene - tert butyl benzene Carbon tetrachloride Chlorobenzene 2-Chlorotoluene, 4-Chlorotoluene Dibromochloropropane Dichlorobenzenes - 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene Dichloroethanes 1,1-dichloroethane, 1,2-dichloroethane Dichloroethenes (dichloroethylenes) - 1,1-dichloroethene, 1,2-dichloroethene, cis and trans Dichloromethane (methylene chloride) Dichlorodifluoromethane 1,2-Dichloropropane, 1,3-Dichloropropene Ethylbenzene Hexachlorobutadiene Isopropyl benzene Methyl tertiary butyl ether (MTBE) and related compounds - Ethyl tertiary butyl ether - Tertiary amyl methyl ether - Tertiary butyl alcohol Methyl isobutyl ketone n-propyl benzene Styrene (vinylbenzene) 1,1,2,2-Tetrachloroethane Tetrachloroethene (tetrachloroethylene, perchloroethylene) Toluene 1,1,1-Trichloroethane, 1,1,2-Trichloroethane, 1,2,3-Trichloropropane Trichlorobenzenes (total) Trichloroethene Trichlorofluoromethane 1,1,2-Trichloro-1,2,2-trifluoroethane 1,2,4-trimethylbenzene 1,3,5-trimethylbenzene Vinyl chloride Xylenes EDB

2

During trials a tentatively identified compound screen for VOCs will also be included

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Halogenated Disinfection By-products Haloacetonitriles - dichloroacetonitrile, trichloroacetonitrile - dibromoacetonitrile, bromochloroacetonitrile Cyanogen chloride/bromide Trichloroacetaldehyde Trihalomethanes (THMs) - Chloroform - Bromodichloromethane - Chlorodibromomethane - Bromoform Haloacetic acids (HAA5) - chloroacetic acid - dichloroacetic acid - trichloroacetic acid - bromoacetic acid - dibromoacetic acid Nitroso Disinfection By-products N-Nitrosodimethylamine NDMA N-nitrosodiethylamine NDEA N-nitrosopyrrolidine Semivolatile Organic Compounds Polycyclic aromatic hydrocarbons (PAHs) - Acenaphthene - Acenaphthylene - Anthracene - Benzo-a-anthracene - Benzo-a-pyrene - Benzo-b-fluoranthene - Benzo-k-fluoranthene - Benzo-ghi-perylene - Chrysene - Dibenzo-ah-anthracene - Fluoranthene - Fluorene - Indenopyrene - Naphthalene - Phenanthrene - Pyrene - Polybrominated diphenylethers (PBDPEs) - Bisphenol A - Caffeine - Triclosan - 1,4-Dioxane - Hexachlorobenzene Alkyl phenol ethoxylates

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Phenols Chlorophenols - 2-chlorophenol - 2,4-dichlorophenol - 2,4,6-trichlorophenol - Pentachlorophenol Alkyl phenols Polychlorinated biphenyls (PCBs) Hormones Ethinyl estradiol 17-B estradiol Estrone Metals Aluminium Antimony Arsenic Barium Beryllium Boron Cadmium Chromium Copper Iron Lead Manganese Mercury Molybdenum Nickel Selenium Silver Thallium Tin Uranium Vanadium Zinc Pharmaceuticals and other substances acetaminopen amoxicillin azithromycin carbamazepine gemfibrozil ibuprofen lipitor methadone

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morphine salicylic acid perindopril Iodinated contrast media (Iomeprol; Iohexol; Diatrizoate) Organotins dialkyltins tributyltin oxide Chelating agents Ethylenediamine tetraacetic acid (EDTA) Nitriloacetic acid (NTA) Other organic compounds Formaldehyde Ethylene glycol 2,3,7,8-TCDD Anions Fluoride Chloride Bromide Iodide Cyanide Nitrate Nitrite Perchlorate Sulfate Pesticides OC - Aldrin - Chlordane - pp-DDT - Dicofol - Dieldrin - Endosulfan - Heptachlor - Lindane - Methoxychlor OP - Non-polar (low levels) - Chlorpyrifos - Diazinon - Dichlorvos - Ethion - Fenamiphos - Parathion methyl - Pirimiphos-ethyl - Azinphos-Methyl

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Pyrethroid - Bioresmethrin - Fenvalerate - Permethrin OP - Non-polar - Carbophenothion - Profenofos - Terbufos - Tetrachlorvinphos - Disulfoton - Ethoprophos - Monocrotophos - Thiometon Fungicide - Carboxamide - Carboxin Fungicide - General - chlorothalonil Herbicide - General - Trifluralin - Pentachlorophenol OP - Non-polar (high levels) - Dimethoate - Fenitrothion - Maldison - Methidathion - Parathion - Pirimiphos-methyl - Bromophos-ethyl - Chlorfenvinphos - Fenchlorphos - Fensulfothion - Formothion - Pyrazophos - Sulprofos - Temephos Insecticide - General - Piperonyl butoxide Herbicide - General - Pendimethalin - Quintozene - Diclofop-methyl General - Propargite

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OP - Polar - Acephate - Trichlorfon - Mevinphos Herbicide - Chloroacetamide - Propachlor Carbamate - Oxamyl Carbamate - Aldicarb - Carbaryl - Carbofuran - Methiocarb - Methomyl - Pirimicarb Herbicide - Chloroacetamide - Metolachlor Herbicide - Triazine - Atrazine - Simazine - Terbutryn - Propazine - Ametryn Herbicide - Triazinone - Hexazinone - Metribuzin Fungicide - General - Fenarimol Fungicide - Azole - Propiconazole - Triadimefon Herbicide - General - Diphenamid - Norflurazon - Napropamide - Propanil - Propyzamide Fungicide - Benzimidazole - Benomyl - Carbendazim - Thiophanate

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Herbicide - General - Nitralin - Oryzalin Carbamate - Thiobencarb - Promecarb Herbicide - Urea - Chloroxuron - Chlorsulfuron - Diuron - Fluometuron - Metsulfuron-methyl Herbicide - Benzothiadiazinone - Bentazone Herbicide - Uracil - Bromacil - Terbacil Herbicide - Acidic - 2,4-D - Clopyralid - Dicamba - DPA - Fenoprop/Silvex - Flamprop-methyl - Picloram - 2,4,5-T - Triclopyr - Endothal Herbicide - benzonitrile - Bromoxynil - Dichlobenil Quaternary Ammonium - Difenzoquat - Diquat - Paraquat Thiocarbamate - EPTC - Molinate - Pebulate - Vernolate

28

Appendix 3
Summary of MAR Forum Outcomes

Summary of key issues raised at the EPA MAR Forums
16/5 GENERAL ISSUES RELATING TO MAR Benefits Reduce pressure on environment and water resources Reduce salt water intrusion Meeting moral obligations Sustainability Reduce waste, reduce ocean discharge Increase (higher quality) water availability Cost; Economics Diversity of options Risks or concerns Encourages more water use, not conservation Public reaction without education; Public values Not soon enough Impacts on aquifer Impacts on downstream environment, stygofauna Accidents can happen Should be only one component of water management Water efficiency in homes, estates Health/Chemicals of concern Further information required Pilot study or trials, long term impacts Further public education; Social issues Understanding of aquifers, their connections Cost; Cost benefit analysis Lack of government direction, who initiates? Need to demonstrate need for MAR Locations of infiltration points MAR FOR ENVIRONMENTAL BENEFITS Benefits More natural than ocean disposal Benefits to wetlands Save higher quality water for drinking Reduce nutrient runoff from urban development Preserve biodiversity Risks or concerns High levels of nutrients Potential to contaminate drinking water Using large areas of land for infiltration Stygofauna Infiltration preferable to injection Chemical interaction in waste stream 17/5 18/5 23/5 24/5 25/5

× × × × × × ×

× × ×

× ×

×

×

×

× × × × × × ×

× × × × × × ×

× × × ×

× ×

× × × ×

× ×

× × × × × ×

× ×

× ×

×

× × × ×

×

× ×

× × × ×

× × × × × ×

× ×

× × × × × ×

×

× × × × × × ×

×

×

Further information required Ongoing research e.g. flora, fauna Locations for MAR Cost, optimal MAR project size Impact on acid sulphate soils MAR FOR HORTICULTURAL IRRIGATION Benefits Benefits for horticulture Provide resource of higher quality, inc quantity Continuation of the industry Decrease fertiliser use, maintain nutrient levels Increase land available to horticulture Establish hort precinct, community benefits Guarantee water quality legislatively Risks or concerns Cost (due to DoH standards), who pays? Free trade agreement implications Land zoning security Wont be able to target nutrients over growing season Implications for people who drink groundwater Further information required Town planning implications

× × × × ×

× ×

× × × × × × × × × ×

×

×

× × ×

MAR FOR GENERAL USE OR MULTIPLE BENE FITS Benefits × Increase viability of existing bores × Reduce pressure on drinking water supply × Improve health of parks and gardens Replace water being extracted from Gnangara Mound Enhance environmental values Energy consumption benefits

× × ×

Risks or concerns Infiltration preferable to injection MAR FOR DRINKING WATER Benefits Climate independent water source Risks or concerns Perception of drinking toilet water (Perception of) taste difference Delay due to ultra-conservatism within govt agencies ×

×

×

×

× ×

Benefits Legislate to make compulsory Possible use of rainwater Reduce overall energy consumption Sustainable living; increased awareness Whole of system approach Smaller pipes, smaller treatment plants Reduce demand on potable water Risks or concerns Legal liability of using the water Overuse of private bores; Licence these? Odour Level of treatment, children could drink Duplication of retic systems and maintenance Residents lose control over household system Contamination of aquifer, especially for drinking Should separate grey and black water

× × × × × ×

×

× × × × × × × × ×

Key issues raised at the EPA MAR Forums

16 May 2005 - Mosman Park
Environmental Benefits Benefits
? ? ? ? ? ? Reduce fluctuations – on environmental resources. Moral obligation not to waste water. MAR – education resource. Keep a balance – saltwater intrusion. Reduces pressure on current resources and horticulture – protection of amenity. Buys time for population policy in place.

Risks or Concerns
? ? ? ? ? ? ? MAR encourages population growth. Does not encourage conservation. High levels of nitrogen and phosphorus to native vegetation (wetland ecosystems). Public education – can be misunderstood. Need to be education programs put in place. Caves (stygofauna) are good bio-indicators of surface water. Not occurring soon enough.

Further Information Required
? ? ? ? ? How does aquifer recharge occur on this region – pilot study into retro-fitting for recharge/infiltration. Education Other agencies demand on water e.g. Pine plantation on Gnangara mound. Current (and ongoing) environmental research – fauna/flora Historical land use and what impacts has this had on ground water.

General Re-use or Multiple Benefits Benefits
? ? ? ? ? ? Avoid waste. Reduce demand for bores. Bores reduce pressure on potable supply. Health/amenity benefit of adequate parks and gardens. Maintain viability of bores. Injection close to sea “more acceptable” then injection to Gnangara (“yuk” factor avoided).

Further Information Required
? ? In future, invite senior high school children to attend forums. Why are we putting any wastewater (including stormwater) into the sea?

Public Drinking Water Supply Risks or Concerns
? ? Perception of drinking toilet water. Need for education on: o OK to drink. o Proper management to ensure health standards are met.

Further Information Required
? ? ? ? ? ? Why is it ok to discharge secondary treated water to ocean but not tertiary treated water to aquifer (perception). How much is used by each user group? e.g. Industry. Impact of “business as usual” is unsustainable. Education is key to acceptance. Cost? 50-100% more of $2 a litre for bottled water “sounds reasonable”. Need “whole system” approach.

Additional thoughts
? ? ? ? ? An education program for the general public on water issues. Pharmaceuticals “buy back” scheme. Why is it acceptable to throw it in the ocean? Public perception – you can do it in the country – education program. Get school teachers on side, kids influence parents.

Irrigated Horticulture Benefits
? ? ? ? ? ? Benefits for horticulture (public open spaces considered a form of horticulture) Salt water intrusion (reducing) Providing a resource of better quality. Frees up water for other uses. Long term sustainability. Economic.

Risks or Concerns
? ? ? ? Effects on existing groundwater/environment DoH standards – high costs? Lack of scientific data. No trials – need: o Field trials o Scale o Chemical reactions o Trials at all proposed sites

Further Information Required
? ? ? ? Costs and who pays? Cost – benefit analysis. Who initiates? Lack of commitment to carry out such a scheme.

Other
? ? ? State of the water/health (contamination etc) Suitable size trials – must be site specific. Lack of data when generating EPA/DoE guidelines.

Integrated Water Management in New Residential Areas Benefits
? ? ? ? ? ? ? ? Possible cost (financial) benefits. May be able to introduce legislation to enforce integrated water management in new residential areas – developers are not going to comply unless they are forced. Possible use of rainwater – benefits from being able to plan the necessary infrastructure. Increased planning for new designs and technology (eg. Planned public spaces) – keeping potable water and stormwater separate – sustainable living. Reducing overall energy consumption. Increased awareness and education of new residents which is transferable to other communities as they move. Increased awareness of water value as a resource. All aspects of water use can be considered – irrigation/gardens (waterwise)/education. Right resource - right use.

Risks or Concerns
? ? ? ? ? ? Health: o Health risks may outweigh potential environmental benefits. o Can we manage the possible health risks of domestic use? Unknown chemicals – question of unknown health risks. Legal liability of using the water. Prohibiting private bores – only licensed private bores. MAR and bores need to have integrated management Over use by private bores (people need to pay real cost of water, environmental cost) – restrictions for bores.

Further Information Required
? ? ? ? ? What’s possible, what’s required? How much do these methods cost? More diagrams may help – a flow diagram to explain integrated water management. More examples of how this would work. Other options and alternatives – Water Corp. inject, others withdraw.

Other Issues
? ? ? Rain water use in new and exciting residential areas. Overall sustainable living – this is just one aspect. Banning all watering in Winter months.

Other comments
? ? Treatment costs should be considered together with transport costs (often treatment is reported alone) The energy intensity of various water supply options should be considered - current system is very high. As energy prices increase, this will have implications. Energy costs associated with proposals should be reported.

17 May 2005 - AQWA
Environmental Benefits Benefits
? A more natural way of disposing of wastewater by allowing it to reach the ocean through the aquifer. Unlike ocean disposal – short circuiting

Risks or Concerns
? ? ? ? Assimilation capacity of the aquifer (risk of choking the aquifer) Accidents happen Potential to contaminate WA’s drinking water Using large areas of land for infiltration ponds

Further Information Required
? ? Look at locations for MAR – where is it best to have MAR? e.g. along the coast to help control the salt water wedge. Cost analysis. What is the optimal size for MAR projects? Must be between singleresidence and large wastewater treatment plant (which takes 1/3 of Perth wastewater). Collecting large volumes of wastewater and then distributing out for MAR may not be efficient – economies of scale.

Other Issues or Comments
? ? ? ? ? ? ? ? What evidence is there that septic tanks were an issue? People had septic tanks and some reported to drink bore water. No problems? Pine trees increase abstraction on Gnangara Mound. Use of alternatives to MAR, e.g. artificial wetlands? Development of other creative solutions. Demonstration projects. Thought: piping wastewater up gradient of the Swan River and injecting to keep the river flowing? Dilute nutrients. Is MAR a bandaid solution? (using ground to clean water). Have other ideas or technologies been considered? Better to put in and leave, rather than use. Urgency of recharge before environmental values are lost. Groundwater dependent ecosystems at risk, will be lost in less than 10 years. Shouldn’t waste time considering minor issues. Asked about the possibility that recharge water may migrate into drinking water sources, the group was quite comfortable with the idea of drinking the treated wastewater given the DoE and DoH safeguards.

General Re-use or Multiple Benefits Benefits
? ? ? ? ? Replace water being removed from the Gnangara Mound, including urban wetlands. Enhance environmental values e.g. wetlands and caves. Direct substitution (not MAR) e.g. for horticulture. Prevent salt water intrusion. Need to target location of MAR to get benefits.

? ?

Use soil-aquifer treatment with MAR Save energy with MAR

Risks or Concerns
? ? ? ? ? ? Education (public participation) (all wastewater should be kept on land) Prefer infiltration to injection, biological processes Public perception of taste difference Don’t risk Gnangara first, need large scale trial (5-10 years) to demonstrate operational/control before transfer to Gnangara. Sites – e.g. urban/ environmental benefits, lakes Need to test hydrogeological modelling with trials Detailed environmental guideline for environmental benefits

Further information required
? Need evidence that scheme would actually work o on Swan Coastal Plain o on-going/extended trial o biological/chemical reduction in aquifer Preferably operate a smaller scheme in metro area for environmental benefits and monitor in detail. Need to demonstrate need – that MAR is more effective and efficient than alternatives. Demonstrate a suburb on wastewater for garden irrigation (3rd pipe)

? ? ?

Other issues or comments
? ? ? Is it worth saving environmental value (e.g. stygofauna)? New residential – need integrated water concept planning. Relocate water demands (fit for purpose) to near source e.g. industry – planning. Only use MAR as a tool where necessary, don’t want long distance transport.

18 May 2005 - Riverton
General (whole group discussion) Benefits
? ? ? ? More water available, provided implemented properly Environmental benefits – wetlands and salt water intrusion Cost of water? Cheaper than canal and desalination

Risks or Concerns
? ? ? ? ? ? ? ? Pricing. Water won’t be valued if too cheap, and therefore wasted. 1/3 of water is used on gardens. Should have more native gardens. Continuous education needed to reduce wastage Why worry about caves or stygofauna? Housing – water features are a waste; Need more water management and conservation. Water efficiency Move forward carefully with back-track option in case of currently unknown problems. This should only be one component of water supply/cycle, and integrated water management

Further Information Required
? Drinking water trials

? ? ? ? ? ?

More information on Gnangara Mound, potential locations for MAR Are aquifers well connected? impact areas known? Results of pilot studies Climate change issue bigger than Gnangara Mound Increase distance between recharge and abstraction? Monitoring and toxicology studies from elsewhere?

Other Issues or Comments
? ? ? ? Provided Dept of Health say is ok, is ok Desalination and clearing projects weren’t fully explained. Salt water from the ocean should be more widely used, e.g. for flushing toilets Third pipe systems result in cross connections

23 May 2005 - Wanneroo
Integrated Water Management in New Residential Areas Benefits
? ? ? ? Technology is available to capture MAR water at subdivisional level Smaller waste pipes to smaller treatment plants Less ocean discharge Saving drinking water supplies

Risks or Concerns
? ? ? ? ? ? Stormwater mixed or segregated? concern Odour Level of treatment (quality), e.g. kids drinking from taps Cost compared with rainwater collection? Duplication of reticulation systems and maintenance Residents loss of use of own household system and forced to use Water Corp system?

Further Information Required
? ? ? Cost of second reticulation system Number of houses per bore Cost of MAR vs cost of household recycle systems

Other Issues or Comments
? ? Would it be more efficient to separate solid and liquid waste before sending to wastewater treatment plant? MAR should be integrated with other water capture systems

Public Drinking Water Supplies Benefits
? new source o climate independent o sustainable approach to resource o recovery from decline, fixing the damage prevent waste of resource cost effective

? ?

Risks or Concerns
? ? ? ? ? ? ? ? ? ? ? Delay due to ultra-conservatism (within agencies) Public perception takes time, need clear drivers People drink groundwater at Carabooda, therefore must be high quality water Need drinking water quality A+ prior to MAR for Carabooda/Gnangara area Water Corporation running it (poor track record and have an interest in the outcome) Lack of social acceptance Water quality – for downstream groundwater use (local drinking) Are Water Corp and Dept of Health talking about same treatment processes? Who will pay for horticultural and environmental allocation of water? Taste of water Equity issue - if water is supplied for MAR upstream of Carabooda, 'substandard' water would be given to Carabooda people (who drink groundwater) to make more 'good' water available for city people

Further information required
? ? ? ? Answers to chemicals of concern trials Better understanding of drivers Willingness of public to pay, and value of the resource (unit value) Understanding allocation and pricing

Other issues or comments
? ? Demand management Behavioural change

Environmental Benefits Benefits
? ? ? ? ? ? ? ? ? Replenishing groundwater Stopping nitrate and phosphate runoff from urban development (not necessary to develop around wetlands) Diversity of options, compared to the other high risk options Mind shift to waste = resource Reduced discharge to marine environment Allow higher quality water to be used for drinking water Taking pressure off other water resources e.g. Gnangara Using existing wetlands for infiltration Rehabilitating wetlands

Risks or concerns
? ? ? ? ? ? ? ? ? Water efficiency – more emphasis required Capturing peoples values to water Impacts on stygofauna diversity Source control – controls on household chemicals THMs and active pharmaceutical products Complexity of social issues associated with MAR. Need to consider environmental issues with social and economic. Impacts to habitats, downgradient impact to surface habitats Lack of co-ordination between government departments, e.g. DPI and EPA. Changes in the characteristics of water

Further information required
? ? ? ? ? ? ? Long term impacts Success of artificial wetlands Information on groundwater system – education required and more research (ecological systems, physical processed) Relationship between environmental and social issues Location of infiltration points Advantages of MAR infiltration over natural infiltration Impacts on acid sulphate soils

Other issues or comments
? ? ? ? ? ? ? Consider using rainwater Consider using artificial wetlands in infiltration process New housing estates should use greywater; New development planning needed Need for community education Need for move higher density housing where water use is less Impacts from climate change More mini golf and indoor gold courses rather than large courses

Irrigated Horticulture (Group 1) Benefits
? ? ? ? ? ? ? Continuation of industry Decrease fertiliser use, maintenance of nutrient levels Increase land availability for horticulture Lower cost than desalination Potential establishment of horticultural precincts, community benefits Guarantee of water quality by legislative means Environmental positives

Risks or concerns
? ? ? Who pays? Costs? Potential for continuation of potable consumption Free trade agreement?

Further information required
? ? ? ? Timeframes Cost-benefit analysis Town planning implications? Marketing

Other issues or comments
? ? Tourism potential? Increased demand for residential land?

Irrigated Horticulture (Group 2) Benefits
? Increase in water availability

? ? ? ?

Carabooda area important for horticulture, MAR has potential to maintain this General support for MAR Potential to increase water quality Benefits to wetlands and caves through MAR

Risks or concerns
? ? ? ? ? Is there a viable horticulture industry to make cost of MAR viable? sustainable? The cost of MAR to horticulturalists may affect viability of industry Land zoning security and security of water provision to horticulture Is MAR water enough? Will it sustain water use requirements in WA, including horticulture? Is the proposed 5 years for implementation too late? Is timeframe appropriate for horticulture?

Other issues or comments
? Consideration of horticultural precincts north of Carabooda due to various landuse pressures, including water supply.

24 May 2005 – Bibra Lake
Environmental Benefits Risks or Concerns
? ? ? ? Flouride Endocrine disruptors – how will they be removed? Chemical interactions in the waste streams Infiltration vs injection. Infiltration preferred.

Further Information Required
? ? ? Travel times in aquifer and biodegradation times What would be done with more concentrated waste following reverse osmosis Impacts on confined aquifers

Irrigated Horticulture Benefits
? Makes sense to use the nutrients

Other issues or comments
? ? Hydroponic igloos Won’t be able to target nutrients over growing season

Public Drinking Water Supplies Risks or concerns
? ? ? ? How protect groundwater drinkers when MAR is used for another application? Breach of human rights to add fluoride to drinking water. Would MAR water be fluoridated? Preferable to drink tap water Deal with perception issues, sell it to the community

Other issues or comments
? ? ? ? Information on travel times, dilution ratios Education. Target schools for education about the water shortage Need more public involvement Chlorination

25 May 2005 – Midland
General Reuse or Multiple Benefits Benefits
? ? ? ? ? ? ? ? Reusing water rather than discarding (we’re not really short of water). Consideration of pricing structure MAR cheaper once running Saving water for future generations Proven elsewhere Consumers become part of the water cycle Future generations won’t think twice, will just be accepted as the norm Nutrient recycling

Risks or concerns
? ? ? ? ? ? ? ? ? ? Would think twice about drinking it Accidents happen Water Corp’s poor track record “shit is always shit” Appears safe now, but in time may find wasn’t e.g. DDT What if vegetables aren’t washed properly? Emerging/currently unknown diseases With MAR, people could become complacent about water use Timelines too long – can’t wait 10 years Is this a political ploy? Will anything really happen?

Further information required
? ? Temperature effects in the aquifer? Up to 50 degrees How deep would water be injected?

Other issues or comments
? ? ? ? ? ? ? ? ? ? Need to educate people on general water use and saving Water is too cheap. Increase price so people use more carefully Water Corp make it sound easy to get more water, so people are complacent. MAR for industrial use? MAR with stormwater rather than wastewater? Are councils investigating water recycling? Re-education is needed Need incentives for new industries to reuse water All government agencies will need to market water reuse well Need to educate people about groundwater flow and age.

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