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| CSIRO | SOLVE | Issue 8 | Aug 06 | |
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ARTICLE
WATER FOR A HEALTHY COUNTRY:
Waste Not, Want Not By Rebecca Thyer
Researchers are exploring options for reusing wastewater and probing community attitudes to recycled waterEach year, Australia’s major cities draw more than 2200 billion litres of water from rivers and ground water sources for industrial, commercial and domestic uses, before expelling 1300 billion litres of it into the sea or rivers. With a drying climate reducing water availability and a growing population increasing demand for water, it raises the question – do we really need to waste this water? It is a subject being addressed by the Water for a Healthy Country Flagship through the Urban Waterscapes program. Sustainable water management is one of Australia’s most pressing issues. Urban Waterscapes program leader Alan Gregory says most cities are at the limits of available natural water sources: “These are likely to diminish further with climate change, so we really don’t have any choice but to explore alternative approaches.
“We have more than enough wastewater and stormwater sources within our cities to meet future water needs, and the technology to achieve it. The challenge is how to configure our water systems to harness these supplies in ways that are acceptable to the community.” Through a systems-based approach, the program aims to model and predict the outcomes of alternative options, develop new water technologies and address implementation challenges. Water recycling is one of the major focus areas, Mr Gregory says. “Recycled water reduces the need to import water from new water sources, it can reduce the loads on ageing wastewater infrastructure, it reduces the pollutant impact on waterways and, with improved treatment technologies, recycled water can be produced to qualities suitable for a range of end-uses.” It is an area being researched by CSIRO’s Dr Simon Toze. He says Australians have always been taught that wastewater needs to be discarded. “But the reality is we are throwing away a valuable resource,” he says. Wastewater is still 99.97 per cent water, and the greatest volume comes from showers, baths and washing machines, with the average person producing 200 litres of it every day. It is delivered via sewers to treatment plants before being dispatched to the sea or rivers. To combat water shortages and quality issues, four places in the world deliberately recycle their wastewater for drinking (as opposed to unintentional, natural water recycling in rivers and creeks). They are California, Singapore, Namibia and the Belgian city of Brugge. Australia – the driest inhabited continent in the world – is significantly not a member of this select group. This is despite the fact that technology exists to treat the water and make it as good, if not better, than a lot of drinking water now consumed. Other uses for recycled water include agriculture, irrigating urban open spaces such as sporting fields, ‘recharging’ wetlands to prevent them from drying out and for dust suppression in industry. It can also be used to recharge aquifers – the natural underground geological formations that store and transmit water to wells and springs. Dr Toze is coordinating a project on managed aquifer recharge (MAR) with the Western Australia Water Corporation. It involves infiltrating treated wastewater into ground water aquifers and reclaiming it as a new water source. The three-year trial at CSIRO’s Floreat site in Perth began last November. About 50,000 litres of treated wastewater from a nearby treatment plant are pumped into the managed aquifer each day to study water infiltration. The project will also assess the human and environmental risks and measure the reduction in pathogens and contaminants during infiltration and aquifer storage. “Basically, we’re studying the ability of aquifers to recycle water and initial results are positive,” Dr Toze says. “We’re finding that we can treat water to whatever degree is necessary to make it fit for purpose and aquifers can help the process. Aquifers have been used for quite a long time as storage facilities, and their value as treatment facilities is now being verified.” Another option being explored by CSIRO is ‘grey’ water use. Grey water is any household wastewater apart from toilet water. Encouraging grey water use is important because it represents a constant water source. Technologies exist to treat grey water biologically, chemically and/or physically to render it safe for uses such as watering gardens, but legislation for treatment plant approval varies between states. To address this issue, CSIRO’s Dr Clare Diaper, with funding from the Victorian Smart Water Fund, is developing a testing protocol for grey water technologies. The protocol will involve a laboratory-based test and a desk-based risk assessment to address variability in grey water quality. Field-based tests have their limitations, which often hinder the adoption of grey water treatment and recycling, especially in regards to grey water variation. Dr Diaper says. “For example, if there are low levels of micro-organisms in the grey water prior to treatment, the field test won’t detect whether they’re adequately treated.” To develop the protocol, Dr Diaper has developed a synthetic grey water containing ‘shampoo, detergent and other bits and pieces’ to mimic real Australian grey water. She says it is important that the protocol can be replicated at other laboratories and that the methods used are easily reproducible, as the plan is for it to become a national standard. A draft version of the protocol should be ready this month. With climate change expected to reduce rainfall and with increasing demands on water, it is crucial that Australia makes the most of the water it has, and assesses public attitudes to water and its reuse. Gauging what is acceptable to consumers is being tackled through an attitudinal model developed by CSIRO’s Blair Nancarrow. It provides, for the first time, a holistic ‘cultural’ framework for evaluating water supply systems. The model helps provide an understanding of the psychology behind acceptability. It allows for water supply systems to be tailored to meet the community’s cultural requirements and provides information to target education and information programs. Ms Nancarrow, director of the Australian Research Centre for Water in Society, says the system is basically a tool for the ‘here and now’ because attitudes will change over time. Consisting of a questionnaire with implementation and analytical instructions, the model should help utility companies make decisions about future water supplies. Companies would use the model to survey customers and decide on the best option for future water requirements. “There are so many different ways of addressing future water supply needs,” Ms Nancarrow says. “Because of that, we needed to find out what is deemed as acceptable to communities. “In the past, industry has tended to look at new water supplies in relation to levels of service – is it drinkable, what’s the water pressure like, is it reliable? We’ve now approached attitudes to water supplies in a novel new manner.” The model is essentially a psychological assessment tool driven by sophisticated statistics. Developers or utility companies wanting to propose new water systems can use it to ask the right questions, assess the answers and find out what will be important to their customers. The model can reduce the time spent arguing points that are not important, she says. “We’ve got a tool that can help see if their systems are going to work. What’s driving it is our 20 years’ experience in water systems.” Ms Nancarrow says understanding people’s attitudes to new water sources is crucial. Not only will it help utility companies and government departments decide on new approaches to water, it will also help drive research priorities. She says it has historically been fairly difficult for utility companies to gauge what consumers regard as acceptable. “It’s very important to know what their attitudes are. Developers may find they receive negative feedback about a proposal and think it needs to be scrapped. “However, by understanding the components of consumers’ acceptability decision making, they might realise that certain aspects of the plan need to be tweaked and that people are not opposed to the idea per se.” For example, she says, people might be worried about a proposal that is only going to be implemented in low-income areas, or in areas where there are lots of children. “But they may not be opposed to the idea as a water strategy.” The model has been tested successfully across different city scales and in different cities. It means water supply systems can be evaluated on a city-wide, neighbourhood and multistorey building scale. She says research shows that people are more concerned about their community than service levels. “It will come as quite a surprise to utility companies that service levels are not important to consumers when thinking about the whole water supply system – what matters most is a long-term, sustainable system. “We were surprised by this outcome. People overwhelmingly wanted sustainable long-term water supplies that were fair and delivered by trustworthy organisations. It had to be all of these things. It just goes to show that people think more at a societal level than a personal level when considering the whole system.”
APPLICATION Improving sustainable wastewater management in response to a drying climate and increased demand for water BENEFIT Recycling would reduce the need to import water from new sources For further information contact: |
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