Water­care’s vi­sion for sewage

Auckland City Harbour News - - YOUR PAPER, YOUR PLACE - JAMES PASLEY

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.

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