Watercare’s vision for sewage
Aucklanders’ future water supply may come in the form of treated sewage.
At a recent forum on the wellbeing of the Manukau Harbour Raveen Jaduram, the chief executive of council controlled organisation Watercare, said it was looking at the possibility of reusing treated sewage for either human consumption, industry, agriculture or reinjection into the aquifer.
‘‘The challenging bit for us remains the effluent,’’ Jaduram said.
‘‘In the rest of the world where they have urgency and pressures for water, they’re now reusing their recycled, treated wastewater.’’
In 2013 the United Nations said that by 2030 nearly half the world’s population could be facing water scarcity.
To combat scarcity issues, treated sewage was already being used in Namibia, Australia, Belguim, Singapore and the United States.
Treated wastewater has had the organic and inorganic solids separated from a liquid waste stream. Currently, once treated it is discharged into waterways.
Watercare communication manager Rachel Hughes said its current infrastructure plan, which goes from 2016 to 2036, did not plan for supplying the public with treated wastewater.
‘‘Currently, we recycle large volumes of treated wastewater at our major wastewater treatment plants and use it for on-site processes such as flushing, cooling and cleaning,’’ Hughes said.
She said the volume of treated wastewater at its Mangere and Rosedale treatment plants was equivalent to the demand of 240,000 people.
Hughes said the potential role of treated wastewater as a water source was well acknowledged.
‘‘We are actively following developments and technology in this area,’’ Hughes said.
Watercare’s biggest challenge might not be cleaning the water but getting people to consume it.
In 2006 in the Australian city Toowoomba wastewater recycling was proposed in a referendum after a severe drought, but more than half of the population rejected the proposal because of the ‘‘yuck factor’’.
Environmental scientist Hamish Lowe said similar work was happening across the country, but it would be more difficult with a large population.
Raveen Jaduram says other countries are already reusing treated wastewater.