Wastewater and conservation key to quenching global thirst

A review prepared by the The University of Melbourne looks at new methods of water conservation and the need to transform policies and attitudes. The paper describes three emerging methods of addressing shortages: substituting high-quality water with lower-quality water where appropriate, creating drinking water from wastewater and reducing leaks and the volume needed for basic services.

‘Taking the “waste” out of “wastewater” for human water security and ecosystem sustainability’, published in a special issue of the journal Science, looks at ways of addressing water shortages around the world through substitution, regeneration and reduction.

Australia’s ‘Big Dry’ in the first decade of the 21st century was a wake-up call to everyone where water was concerned. Parched cities and regions across the globe are using sewage effluent and other wastewater in creative ways to augment drinking water, but four billion people still do not have adequate supplies. Wildlife, rivers and ecosystems are also being decimated by the ceaseless quest for new water and disposal of waste. The paper states that changing human behaviour and redoubling the use of alternatives are critical to breaking that cycle.

“This is the only path forward to provide water for humans as well as for ecosystems,” said lead author Stanley Grant, Professor at The University of Melbourne’s School of Engineering with a joint appointment at University of California, Irvine, who specialises in water quality. “We need to focus on improving the productivity and value of existing supplies, which basically means getting more out of a glass of water.”

Co-author Dr Michael Stewardson, Discipline Leader in Hydrology and Water Resources at The University of Melbourne’s Department of Infrastructure Engineering, says Australia is leading the world in tackling the challenge of water scarcity: “We understand the need to grow the value we get from scarce water for food security, energy generation, ecosystem health, industrial use and cities.”

From California to Melbourne, to Israel and Brazil, the researchers found that homeowners and major utilities are capturing liquid sewage, highway runoff, household laundry water and rainfall. In some cases, alternative sources are a major contributor to replenishing water. Elsewhere they are a drop in the bucket.

Altering individual habits could be tougher. Turfgrass still consumes nearly three-quarters of residential drinking water in arid areas of the US. Homeowners may eventually have no choice but to replace lawns with drought-friendly landscapes. Engineered wetlands and other ‘biofilters’ that capture storm water runoff are also part of the solution.

“These complementary options make the most of scarce freshwater resources, serve the varying water needs of both developed and developing countries, and confer a variety of environmental benefits,” the researchers conclude. “Their widespread adoption will require changing how freshwater is sourced, used, managed and priced.”