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Country Water Action: Australia
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With their livelihoods in jeopardy, the McLaren Vale grape growers found a solution about 15 kilometers away, at Christie's Beach where treated wastewater was being dumped into the sea. The nitrogen-rich effluent was killing marine life, but that didn't render it useless.
Wastewater has all the right nutrients that soil craves and, with the right treatment, can be a safe, affordable and sustainable source of irrigation water. The effluent from the Christie's Beach processing plant undergoes secondary treatment and is disinfected with chlorine. With a Class B rating, it is safe for agricultural irrigation so long as safety standards are kept by workers and a spray or drip irrigation system is used.
The growers found government support at all levels, including from the South Australian Water Corporation, the government utility responsible for all water supply and treatment, which offered the wastewater at no charge.
South Australia is often called the driest state on the driest continent. And for that reason, the government has been forced to think innovatively about where it gets its water and how it uses it. The state's regulatory and policy framework supports reuse and the national government policy calls for the phasing out of all effluent discharge into the marine environment.
"The situation had the essential elements for a financially viable water reuse project that could be attractive to the private sector," writes Thiyagarajah.
To get the scheme they wanted, growers needed private sector help to oversee water delivery, billing, and collection. Any private sector group, though, would want to know that their legal rights and investments were protected if they were involved.
Gaining private sector interest was made easy by securing the right regulatory and policy framework that set tariff rates that were both affordable for the growers and would cover the costs of operating and maintaining the system.
The plan called for the construction of a 24-kilometer pipeline that would connect McLaren Vale vineyards to the treatment plant at Christie's Beach. The pipeline would be made of 500mm diameter PVC pipe and include all the associated spur mains to deliver 10,000 Mega Liters (ML) per year to the growers.
The growers who wanted to be included in the distribution system were required to pay for their share of the pipeline and the drip irrigation system, both of which were designed by the same company to ensure uniformity. In total, the 24-kilometer pipeline system cost growers USD$5.5 million. No government subsidy or funding supply was approved for the scheme.
In 1997, Chapel Hill Winery Pty Ltd. became a 10% joint venture partner (outlaying $697,000) in the Willunga Basin Water Company, the private entity set up to build and operate the scheme. By 2002, the company says it ceased drawing on the aquifer for vineyard water and cuts its use to only 10% of its 50 ML licensed allocated groundwater. According to the company's website, 100% of waste is recycled and reused on site.
As a result of the scheme, the grape growers are now spending less on fertilizers and water supply, using less groundwater and producing more crop than ever before. Wastewater is half the cost of groundwater and 65% of the cost of potable water. Wastewater also has lower salinity levels-good news for crops.
Demand for the wastewater has also risen, leading to the expansion of the pipeline to 70 kilometers. The original investors in the scheme, however, pay a lower tariff to compensate them for the initial investment costs. The scheme's private sector entity has also been able to pay dividends to shareholders, reflecting a financially robust company, Thiyagarajah notes.
Despite the success of the scheme, the growers currently need only 40% of the wastewater available from the Christie's Beach treatment plant. What goes unused by growers continues to be dumped in the sea. Thiyagarajah suggests that the scheme could be greatly expanded in the region as well as made to provide off-peak winter storage for peak summer reuse through aquifer storage and recovery projects or building of surface storage dams.
Thiyagarajah recommends that governments, utilities, and private sector entities that are considering a wastewater reuse scheme should seriously consider adopting those practices that made Adelaide the success that it is.
Up-front, invest in a thorough financial and technical feasibility study, which will determine the scheme's long-term viability and help to attract private sector funding
Follow best irrigation practices through soil surveys, reviews of on-farm irrigation systems and headworks, regular soil and crop management reports and seminars, backed by regular independent monitoring and audit
Follow independent and competent design and tendering process, which will ensure technical integrity of the scheme and thus minimize potential problems in the future
Agree and approve a tariff structure that is affordable yet ensures the financial sustainability of the project
Apply appropriate instrumentation and telemetry that monitors and control's each customer's off-take
Secure commercial arrangements and agreements that allocate risk appropriately between the government, the water operator, the management company, and the farmers
Create an irrigation management plan that is scrutinized and monitored by various government agencies to ensure the sustainable management of the reclaimed water irrigation scheme
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