Nearly 10 percent of Australia’s sewage effluent is being recycled in one form or another. The extent of recycling in Australia in 2001-02 is shown in Table 1.

Recycling of water from wastewater treatment plants has been widely practised in much of rural Australia, with the treated effluent being used for local playing fields, golf courses, ovals, racecourses, cemeteries and other amenity uses. Some water treatment authorities have also developed complementary agricultural or forestry uses. The introduction of increasing standards required by environment protection agencies for effluent discharge to oceans or watercourses has encouraged effluent from plants to be diverted from river, estuarine and ocean discharge to land application in association with agriculture. However, these recycling projects represent only a small proportion of the potential for recycling of water from Australia’s wastewater treatment plants.

Until recently, use of recycled water in the major cities has been very small, being primarily oriented to urban amenity plantings. The extent of reuse from the capital city treatment systems is given in Table 2.

Very little of the currently used recycled water, apart from some minor uses such as on football ovals and bowling greens, results in savings in drinking water. However, the reduced availability of water resources through drought and the need for water allocations for the environment is now encouraging the substitution of recycled water for existing supplies of drinking water in Australia’s cities where drinking water standards are not required. Opportunities include for toilet flushing, urban garden irrigation, car washing, fire fighting, community amenity plantings, playing fields maintenance, provision of water back to the environment and various industrial uses such as boilers, cooling water, industrial dyeing and concrete batching.

A recent review (Radcliffe 2003) has summarised water recycling currently practised and additional proposals being considered in Australia. A variety of approaches have been taken to capturing the opportunities for greater use of recycled water, whether for land-based application of treated effluent or to make savings in drinking water resources. A description of the principal categories of water recycling follows.

Examples include seven schemes in place for irrigating parks, and golf courses in Sydney; the use of effluent in Canberra to maintain the grounds of Duntroon Military College with projected expansion to Ainslie and O’Connor; the use of recycled water in Melbourne from the Werribee STP for the nearby tourism precinct and for the development of golf courses near the Carrum STP; and the introduction of recycled water in Perth to the McGillivray Oval.

There have been numerous examples of water recycling in country areas for land-based applications encompassing sugar cane, viticulture, floriculture, turf grass, pasture production, hay cropping and vegetable growing. Uses are limited by the standard of treatment undertaken in the STP, the highest level being required for salad vegetables. In some cases, the treated effluent is used on farms operated by treatment utilities and in other cases by contract supply to commercial growers. However, depending on annual rainfall patterns, schemes for plant-based agricultural and urban amenity use can have very seasonal demands (Figure 1) and may require expensive major associated storages or conservation techniques such as Aquifer Storage and Recovery (ASR).

The move to land-based applications has provided opportunities for economic development, recent examples including the introduction of tertiary treatment and distribution to an expanding group of Northern Adelaide Plains vegetable growers, a self-funded distribution scheme for the new plantings of Adelaide’s Southern Vales grape-growers, and the conversion of Nowra dryland dairy farmers through the Shoalhaven Water ‘REMS’ scheme to irrigated pasture production, providing increased productivity and long-term viability in the face of dairy industry deregulation while also underpinning continuity of operation for the local dairy factory.

Schemes currently being examined include development of agricultural land on the Werribee Plains for irrigated horticulture at Balliang, and an expansion of agricultural enterprises through the Cranbourne-Koo Wee Rup corridor in Victoria. However, it can be difficult to meet the economic expectations of proponents. An ambitious scheme to take recycled water from Brisbane, Logan and Ipswich to the Lockyer Valley and the Darling Downs has been declared unviable by the Queensland Government, as it would potentially have involved subsidies of between $1 million and $2 million per farm (Barton, 2003).

Industrial uses are attractive to water treatment authorities as they usually have less seasonality of demand than agricultural and amenity uses. An advanced water reclamation plant at Luggage Point STP is now supplying up to 14 ML/day of boiler feed water to the Brisbane BP-Amoco refinery. The Illawarra Wastewater Strategy, now being implemented, involves upgrading the Wollongong STP to produce 20ML/day for BHP Steel using microfiltration and reverse osmosis with concomitant savings of the drinking water currently being used. The proposal to upgrade the Glenfield and Liverpool STPs in Sydney, and to forward up to 100ML of recycled effluent/day through a 53 km pipeline from which sales to industrial and amenity users are to be made, before discharging the remainder through the Malabar outfall, will serve to both improve environmental standards in the Georges River and substitute for drinking water now being consumed. In Perth, new industries in the Kwinana Industrial Strip are unable to access groundwater, and can have only limited access to drinking water supplies, but the Kwinana Water Recycling Project, due to be commissioned in 2004, will make available 5GL/annum of water by microfiltration and reverse osmosis from the Woodman Point STP for industrial use.

Stormwater is also being adopted as an alternative water resource to replace drinking water where the latter’s standard is not necessary. In South Australia, the Corporation of the City of Salisbury has been innovative in stormwater conservation, initially for its own parks and gardens. Recently, it completed a jointly-funded venture to store and treat stormwater on Parafield Airport to provide over 1GL/annum to GH Michell & Sons, Australia’s largest wool processor. This water is arriving at a lower salinity than the drinking water it replaced. A further project involves providing harvested stormwater to Holden Ltd vehicle manufacturing operations and other industrial users at Elizabeth. Biological treatment in wetlands underpins both projects. The possibility of harvesting and treating Adelaide’s urban stormwater has also been considered (R Freeman, Department Water, Land and Biodiversity Conservation, pers comm).

Collection of rainwater in domestic tanks can also be regarded as a further form of stormwater recycling. Household rainwater has been widely used for drinking in much of Australia, particularly in rural areas and Adelaide. However, there are some health risks, and these can be increased if the rainwater collection system is not maintained in a clean condition. In consequence, rainwater tanks have been discouraged in some Australian cities. Economic studies show that their installation is an expensive form of conservation and may not repay the capital invested within the lifetime of the tanks, though their use may heighten awareness of the value of water and the need to conserve it. In the last couple of years, government subsidy schemes have been in place to encourage the installation of domestic rainwater tanks in Sydney, Melbourne and Perth, though uptake of the subsidy has been modest.

Incorporating recycled water in new housing developments, whether from recycled effluent or from stormwater, provides opportunities to reduce demands on drinking water supplies. On the outskirts of Sydney, a residential ‘third pipe’ scheme incorporating recycled water from the Rouse Hill STP, which can treat 4.4ML/day with ozonation, microfiltration and superchlorination, is now servicing 12,000 homes. The first deliveries of ‘reuse’ water were made into the system on 31 July 2001. At Homebush, the Sydney Olympic Park Authority has developed an integrated effluent/stormwater system as input to its microfiltration-reverse osmosis plant to provide recycled water to Olympic Park and the adjacent suburb of Newington through a ‘third pipe’ system. Mawson Lakes, an Adelaide development area with a proposed residential population of 10,000, a university campus of 5,000 students and a resident workforce of 10,000 has been designed to accommodate dual reticulation through a ‘third pipe’ system. Its sewage is to go to the Bolivar STP for advanced treatment and recycled water will be piped back for mixing with stormwater harvested by the Salisbury Council. Dual reticulation to 9,000 residential dwellings is being developed in the new suburb of Aurora, at Epping North, 25 km from Melbourne. Rainwater will be captured from residential roofs and passed through the domestic hot water systems, effectively pasteurising the water before use. Recycled water schemes have also been evaluated for a possible Heathwood/Brazil development in Brisbane and are being explored for a 150,000 resident project at Pimpama-Coomera on the Gold Coast. In all these schemes, ‘purple pipes’ must be used for reticulation of recycled water to minimise the risk of cross-connection to the drinking water system.

Recycling of water through on-site treatment plants can provide an alternative approach to the installation of major infrastructure. Domestic-sized wastewater treatment plants in each of six houses in urban Canberra, commencing operating in 1994-95 using two alternative treatment processes to reclaim water for toilet flushing and garden watering. In Melbourne, a 236 unit housing development at Inkerman Street, St Kilda, has incorporated recycling of domestic greywater (bathroom basins, baths and showers), from about half the units in four buildings using an activated-sludge (aeration) tank, with secondary filtration in a 400 square metre native wetland and sand filtration on the site. There is recycling of the combined grey/stormwater for sub-surface garden irrigation and toilet flushing across the entire development. A further example of on-site recycling is the refurbished building occupied by the Australian Conservation Foundation at 60 Leicester Street, Carlton, incorporating an in-house biological STP, with water from it being used to flush toilets and irrigate the internal and rooftop gardens.

Using membrane technology housed in transportable containers, small scale plants can be used to draw effluent from trunk sewers in a process called ‘sewer mining’, the reclaimed water being available for non-drinking purposes. Experimental installations have been tested in Melbourne’s Domain Gardens and Albert Park, in Brisbane at the South Pine sports complex and on the Gold Coast. A further sewer-mining project at Flemington Racecourse, facilitated through Victoria’s Smart Water Fund, will demonstrate 100kL/day Multiple Water Reuse Technology developed by the CRC for Waste Management and Pollution Control, and licensed to Zeolite Australia Ltd. A potential expansion in the use of small-scale plants within new high-rise office and apartment buildings could underpin a new service industry required to successfully maintain and operate these plants with the necessary level of quality assurance.

Most of Australia’s cities are forecast to continue growing. Migration to Australia is likely to continue. Significant changes are also occurring in the demographics, social attitudes and wealth of Australian communities, potentially stimulating the growth in water consumption. Evidence is emerging that this wealth is generating increased water use, principally on gardens, offsetting the success of demand management in recent years. The introduction of policies involving charging for water on a volumetric basis since the mid-1980s has brought about reductions in domestic demand of up to 30 percent and has provided a ‘breathing space’ for water agencies to identify future approaches towards provision of water services. However, it will be more difficult to achieve future savings either through additional efficiency measures, or water restrictions. The most cost-effective approaches to reducing growth in water consumption have now been implemented. Policy makers and water utilities now have to address the future.

Using an integrated water cycle approach for water supply management has the capability of maximising the use of available water resources while offering significant benefits in more efficient use of capital. This includes:

• the sensitive water harvesting from catchments to ensure environmental needs are met as well as securing water for community use;

• managing stormwater run off in urban areas within the same philosophical framework to reduce the need for stormwater infrastructure and flood mitigation investment while providing an additional source for water conservation;

• incorporating household rainwater tanks which as well as conserving water and providing a harvesting capacity from short periods of rainfall that do not generate flows to reservoirs, can usefully reduce stormwater surges in urban areas; and

• using recycled water, treated to standards appropriate for projected uses, as an aid to conserving reticulated drinking water.

A 27 unit residential development at Fig Tree Place (Newcastle) has shown a 60 percent saving in reticulated drinking water use through capturing rainwater and stormwater for use within the development (Coombes 2000). Integration of stormwater and rainwater capture within the Hunter Valley has been modelled to save 50 percent of mains water use, and reduce peak demand by 25 percent. Yet, within the capital cities, very little use has been made of recycled water as an aid to underpinning our water resource management.

However, there have been major changes in the approaches of many participants in the water industry and in policy arms of government. Minds that were focused by the 2001-03 drought, are also considering the impact of possible longer-term surface water harvesting limitations induced by climate change. Furthermore, the regulated allocation of water for the environment has reduced the accessible yield of some historically used watersheds and reservoirs, a process now strongly established in Sydney but likely to be more forcefully followed in other cities. Integrated water resource planning is being adopted, taking account of the entire water cycle. Canberra, Melbourne and Perth have been set targets to recycle 20 percent of their wastewater. The drivers for recycling, previously dominated by the need to meet standards for outfall discharges to watercourses and marine environments, are increasingly driven by the realisation that accessible urban water resources are limited. Saving drinking (potable) water by substituting it with recycled water for non-potable uses has become more attractive.

Nevertheless, there are issues to be addressed. There is evidence that some agricultural projects are being driven by central agencies with a strong imperative to ‘get runs on the board’. Projects need to be able to model the likely long-term impacts as well as identifying the short-term benefits. Past experience with irrigation development suggests that rises in groundwater level and salinity are common, dependent on the inherent hydrogeological setting of the area. There are risks of waterlogging, and seasonally perched watertables and consequent impacts on beneficial groundwater quality (Bluml 2002). Rising water tables have been already observed in the quaternary aquifers underlying the Northern Adelaide Plains serviced with reclaimed Bolivar effluent in South Australia (Zulfic 2002). Discharge to land does not always lead to the best environmental outcomes and can make water recycling more difficult (SKM 2002).

There can also be environmental impact difficulties for water utilities in changing their operations, with potential for the Commonwealth Environmental Protection and Biodiversity Conservation Act 1999 being invoked in the light of possible effluent disposal practice changes impacting on threatened biodiversity (KBR 2003, YVW 2003).

There is great variability in pricing of recycled water in Australia. Costing and pricing mechanisms are not transparent. The true cost of neither drinking nor recycled water is reflected in current prices. A lack of integration in drinking water, sewage, stormwater and groundwater resource management can result in irrational use of resources and failure of market forces. There is evidence that the availability of cheap recycled water at 28c/kL for garden use at Rouse Hill has increased total water consumption. The true cost of recycled water currently provided from the Rouse Hill STP has been estimated at $3 to $4/kL when the scheme is completed (de Rooy and Engelbrecht 2003). The price of recycled water at Olympic Park/Newington is 83c/kL, but the direct operating cost alone is $1.60/kL. (The price of drinking water from Sydney Water in 2003 is 98c/kL.) Externalities such as impacts on the environment are generally not costed. Often the cost of capital has not been accounted for in determining recycled water costs or prices. There has been dependence on grants to cover the shortfall between willingness to ask users to pay and the actual costs of a project. Such grants become de facto provisions for externalities, notably through the Natural Heritage Trust’s Coasts and Clean Seas Program that was instrumental in establishing several coastal STP effluent recycling projects from the 1990s, but which went into recess in 2002.

There is a risk that a potentially large number of recycling projects initiated with economic development as a primary driver, for example increased horticulture, may not have sufficiently addressed the market responses to additional commodity production and a subsequent risk of depressed prices. Such proposals, if not tied to a reduction in drinking water demand, will offer little in net resource and environmental benefits. Water conservation, demand management and recycling opportunities need to be considered together in the development of pricing policies and investment decisions.

There are inconsistencies between governments in the management and regulation of their water resources and water services. An integrated water cycle management anomaly has been evident in the National Water Reform Agenda, which examines the effectiveness and efficiency of Australia’s water and wastewater services, but until recently has excluded reuse water from its considerations (R Campbell, NCC, pers comm). The States Regulators’ Forum has given little attention to water, and some states, including Victoria, South Australia and Western Australia have had no effective price regulation (L Owens, Essential Services Commission SA, pers comm). There can be a conflict of interest within government with regard to water management, with water resource managers seeking to restrain per capita consumption, and state-owned water utilities having an obligation to maximise returns to their principal shareholder, the state government. The dividend from SA Water to the South Australian Treasury after tax was 119 percent in 1998-99 and 124 percent in 1999-2000 (NCC 2001). The ownership and management of water can also involve inter-jurisdictional issues, particularly where overland flows may be from one jurisdiction to another. Although the management of surface and groundwater may be vested in the state, there are examples of local government harvesting stormwater, storing it in a prescribed groundwater resource, withdrawing it within its groundwater entitlement and becoming a de facto water utility by entering into marketing contracts to provide water for industrial use.

There are concerns about that lack of standards for parasites and viruses in the current ARMCZANZ/ANZECC (2000) reclaimed water guidelines, and these are to be reviewed. Possible risks from endocrine disruptors also give concern. Redrafted Australian drinking water guidelines (NHMRC/ARMCANZ 1996) are expected to be available by late 2003 (P Callan, NHMRC, pers comm). Public perceptions of recycled water remain sensitive. In consequence, the regulatory setting tends to be very risk-averse. There can be different perceptions between jurisdictions in their interpretation of the precautionary principle, creating lengthy decision-making processes, with the uncertainty leading to a disincentive for investment. There also can be inconsistent responses by industry. For example, a major food processor accepts produce irrigated with recycled water in one state, but will not accept the same commodity grown with recycled water in an adjacent state (J Kelly, Horticulture Australia, pers comm).

There appears to be a need to review the regulatory environment to integrate health and environmental standards, service provision and financial regulation. At the moment, these regulatory systems appear quite disconnected, and there is a tendency to be prescriptive in what has to be done rather that prescriptive of the outcomes required (Cullen 2003). The Natural Resource Management Ministerial Council in April 2003 asked its Standing Committee to consider and report back on water recycling and water-sensitive urban design as a mean of taking an integrated whole-of-water cycle approach to water management. The Environment Protection and Heritage Ministerial Council at its May 2003 meeting agreed to work with NHMRC to review and update national guidelines for water recycling, working in partnership with the Natural Resource Management Ministerial Council. A presentation entitled ‘Recycling Water for our Cities’ is to be made to the Prime Minister’s Science, Engineering and Innovation Council in November 2003.

Increasing public knowledge and understanding of these issues is essential before meaningful debate with the community can occur. To ensure the level of community trust for proposals, honesty, transparency, adequacy of information and listening to public concerns are fundamentals to the implementation of innovative recycling schemes. The community must participate in early stage discussions over future water management, recycling and conservation options and be involved in identifying the preferred solution. Gold Coast Water is currently following this approach in exemplary fashion for Queensland’s newly developing Pimpama-Coomera area.

There have been examples where communities have been presented with a single proposal and asked to accept it. Such belated token consultation, effectively constrained by decisions already taken, can generate significant opposition in principle and lead to a loss of trust in the agency proposing the solution. The public is particularly concerned about any issues that have a potential to impact on the quality of life, health and public safety and very quickly becomes negative to the whole concept if trust is lost in the source of information.

Direct potable water reuse refers to the merging of drinking and non-drinking water supplies in the distribution system after both supplies have left their respective treatment plants. The option of direct potable reuse is the most technically demanding but quite feasible. However, it is potentially contentious among consumers because of the negative associations of wastewater. Community group reactions in areas where direct potable reuse has been proposed can be strongly negative due to a health and hygiene concerns. These concerns are further intensified by the potential problem associated with wide range of chemicals, chemical compounds, unidentified organic compounds and pharmaceuticals that are detectable in wastewater and may subsequently be present in recycled water. Such proposals also provide opportunities for political opportunism. Currently, only Windhoek in Namibia and Singapore recycle water directly into the drinking water system.

The Singapore microfiltration/reverse osmosis system is very recent, having been installed due to limited catchments and concerns regarding security of water supplies from Malaysia. Water authorities have been quite transparent about the technology, and reinforce its acceptance through regular visits by community groups, particularly school children, to the recycling plant. Even so, most of the current output is used industrially, with only about 1 percent going into the drinking water system.

By contrast, the use of ‘indirect potable recycling’, in which treated water is discharged from a plant into a stream and then subsequently accessed as a water resource downstream, can be widely accepted. There are numerous examples, including Canberra’s Lower Molonglo STP discharging into the Molonglo and Murrumbidgee Rivers to Burrinjuck Dam, and Adelaide’s Hahndorf STP discharging into the Onkaparinga River to flow to Mount Bold Reservoir.

McDonald (2002) has shown that if 50 percent recycling were achieved in Melbourne by 2020, it would allow replacement of 35 percent of the drinking water currently used, providing the opportunity for deferment of additional infrastructure for up to 50 years.

Recycled water schemes have relatively high capital, operating and maintenance costs, but they have potential to provide significant economic, social and environmental benefits. Australia is now embarking on a major evaluation of these benefits. To achieve value for its $300 million per annum investment policies in STP upgrades, institutional, pricing and regulatory reforms must keep up with the pace of technological developments in water conservation, and in the storage and treatment of reclaimed waters.

Access to safe water supplies and provision of sanitation systems are regarded as indispensable components of public health infrastructure. Maintenance of this infrastructure and the separation of drinking water and wastewater has been a cornerstone of the major improvements in public health since the mid-nineteenth century. On the surface, using recycled water to replace current uses of potable water in a domestic environment could be seen to reverse a basic public health tenet of keeping these two types of water apart. One publicised failure could undermine every recycling scheme being developed or operating (SKM 2002). This could result in a major loss of demand, putting at risk the capital invested in reuse systems. It needs to be recognised that there is no security of demand in the face of disaster (GHD 2002). Nevertheless, there is considerable scope for Australians to use their water supplies a second or even a third time around.

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