Solution to pollution not dilution - experts

From the ODT
By Michelle McCullough on Thu, 18 Dec 2008

To promote Dunedin as the wildlife capital of New Zealand is ridiculous, given the city's sewage-contaminated beaches, two wildlife experts say.

Former Dunedin penguin researcher John Darby, who now lives in Wanaka, is concerned the second stage of the Tahuna Waste Water Treatment Plant upgrade will still not be good enough when it comes to the area's wildlife.

‘‘The proposal, even with the extended outfall, is to pour poorly treated waste out to sea and, given the vagaries of tides and currents offshore of Otago Peninsula, I am far from convinced that this resolves much by way of disease entities and contamination of the marine ecosystem,'' Mr Darby told The Star this week. ‘‘From a commercial point of view, it is ridiculous to be promoting Dunedin as the wildlife capital of New Zealand and at the same time closing beaches and restricting shellfish harvesting because of sewagecontaminated beaches.''

Former vice-president of Protect Our Ocean (Poo) Andrew Brown agrees. ‘‘If we want to continue to market ourselves as the wildlife capital of New Zealand we need to sort it out. It's an embarrassment,'' Mr Brown said. ‘‘Dunedin exists on thirdworld treatment facilities and it's been a city disgrace for more than 100 years.''

Both men echoed the concerns of surfers raised in last week's Star, in reaction to the possibility the second stage of the plant upgrade might have to be deferred because of the global economic climate. The possibility had been raised in earlier comments made by Dunedin city councillor Richard Walls.

Cr Walls did not wish to comment further when contacted yesterday, but earlier provided a response to The Star's front page article last week (see Page 5).

Mr Darby was ‘‘appalled'' there was any suggestion that the commissioning of the new outfall should be delayed any further, ‘‘nor am I happy that the DCC still considers that the solution to pollution is dilution,'' Mr Darby said. Mr Brown also fears the council will opt for chlorine disinfection instead of the secondary treatment system in order to meet the biological guidelines set down by the Otago Regional Council.

Former Poo member Dr Marc Schallenberg agrees that chlorine disinfection, which is banned overseas, would be unsatisfactory. ‘‘Adding an environmentally damaging chemical to sewage is no longer an acceptable way to treat waste, especially if it's going to be discharged to an ecosystem,'' Dr Schallenberg said. When contacted by The Star, DCC infrastructure services committee deputy chairman Bill Acklin said the council would receive a report on February 2 outlining recommendations for secondary treatment options.

With the outfall pipe expected to be operational in January, Cr Acklin saw no reason why the second stage of the upgrade would not go ahead. ‘‘It's now time to get into treatment and I don't see why it would be deferred. The funding is already in the budget, and the price is what has been budgeted for.'' Cr Acklin was unaware whether the use of chlorine was an option but predicted the second stage of the Tahuna upgrade would be modelled on the Green Island Wastewater Treatment plant.

Tahuna Wastewater Treatment Plant upgrade project manager Brian Turner said the council had never considered dilution of wastewater as a secondary treatment option. ‘‘We have never looked at diluting the waste because all discharges get diluted anyway.'' Mr Turner is adamant chlorine disinfection will not be an option for the secondary treatment plant.

Department of Conservation (Doc) spokesperson Liz Sherwood said there was no hard evidence to back up claims of wildlife experts that current waste discharge from the Lawyers Head outfall was having negative impacts on costal Otago wildlife. ‘‘Doc has no evidence that the Tahuna discharge is having an adverse effect on indigenous wildlife, including yellow-eyed penguins,'' Ms Sherwood said. ‘‘The department supports DCC's moves toward secondary treatment of human waste, which would greatly minimise the risk of human/wildlife disease transmission.''