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Stratford oxidation ponds have new lease of life

Friday 31 October 2008, 6:55AM

By Stratford District Council

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Stratford Oxidation Ponds - the rock contact filter
Stratford Oxidation Ponds - the rock contact filter Credit: Stratford District Council

STRATFORD

The aging Oxidation ponds in Stratford have undergone a makeover that means they are ready for the busy holiday period.


Stratford District Council Operations Manager John Jones says “the old wastewater treatment system could no longer treat effluent to the required standards. In winter the oxidation ponds were unable to treat the effluent adequately because of the large volumes of storm water entering the system. Also the unacceptable level of nutrients that used to be discharged into the Patea River increased the risk of algal bloom during the summer months due to the warmer temperatures and slower river flows.“


“We needed a new resource consent from the Taranaki Regional Council,” John says, “and during that process we identified ways we could upgrade the system to meet their requirements and create a more efficient water treatment system with greater capacity.”


The new resource consent requires the upgrades to be complete by June 2009, but the project was brought forward to be completed before the summer months. Harrison & Grierson Consultants Ltd were contracted to do the upgrade work, which finished in October. Ash Deshpande from Harrison & Grierson said “the Stratford District Council approached us to develop options for improving the quality of treated effluent being discharged to the river. Upon some preliminary investigations, it was decided that the recommended option should improve organic capacity of the ponds, and improve effluent quality.


“The total cost of the project will be $1.2 million, but it has to be done,” says John Jones. “Raw sewage contains matter that could be potentially damaging to our ecosystem, such as bacteria and parasites. Untreated, it can be harmful to marine life and plants as well as cause illness to humans by spreading disease.”


Oxidation ponds treat raw sewage by converting organic matter into inorganic matter using bacteria. The inorganic matter is then treated and gradually released.


“The upgrades to the Oxidation ponds increases the capacity of the facility, and treats the effluent to a much higher standard than before. This will stand Stratford in good stead for the future” John says.