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New pipes to separate city's industrial waste

15 Jun 2010

New pipes to separate city's industrial waste

As buildings make their presence known in Banks Street as part of the city’s wastewater upgrade, a vital link in the new system has been less obviously getting on with business.

Since late March, half a dozen Downer EDI Works staff and their assorted machinery have been beavering away laying the first pipes for a network reaching from the Bernard Matthews-Juken NZ mill area into the Banks Street plant. This will enable industrial and domestic wastewater to be separated and pumped to the city’s new treatment plant.

The work is part of the $1.1m contract for the western industrial pipeline awarded to Downer EDI Works, which is included in the total $39.5m wastewater project. Separating industry wastewater halves the cost and size of the treatment plant that would otherwise be needed to treat combined human and industrial waste.

Gisborne District Council projects engineer Michael Yukich says that trade waste and domestic wastewater from the western industrial area are currently discharged through the same pipe and pumped back to the Stanley Road milliscreening plant.

By the end of the year, these wastewater streams will be separated into two pipes before being pumped to the new Bank Street Wastewater Treatment Plant. The domestic sewage will be treated in the new biological trickling filter plant and the trade wastewater will go to the pre-treatment building for milliscreening before both are then discharged through the existing outfall pipe to the sea.

Mr Yukich says the contract involves building a new pump station near Bernard Matthews in Dunstan Road, upgrading the existing McDonald Road pump station and installing 8km of pipeline. The main PVC pipeline being laid has the capacity for other industries to join as required, thus catering for the greater volumes of wastewater predicted as part of future development.

“To date, a section of pipe has been laid from the location of the new pump station at Dunstan Road to the existing pump station in McDonald Road. Work has now started on laying pipes along the state highway to Banks Street.

“The first section of pipe will receive waste from Bernard Matthews, the council’s new dog pound facility and eventually Hikurangi Forest Farms mill. All this waste will be collected in the new Dunstan Road pump station which will be installed next month, weather permitting. The whole project will be completed in time for the commissioning of the new Banks Street facility.”

Meanwhile, Connell Contractors have made a good start on the main wastewater conveyance pipelines from outside the on-site outfall pump station to Banks Street itself. These pipelines -- which will take screened and treated wastewater to the existing outfall – will be installed down Banks Street and around the existing Stanley Road treatment site.

Nearby in Banks Street, the pipe bridge across Waikanae Stream, which takes wastewater from the Awapuni industrial area, has been upgraded and is now ready to have the new larger carrier pipe attached.

Council's wastewater project manager Peter McConnell praised businesses in the Banks Street area for their cooperation as pipe-laying work squeezed their working areas.

He said local contractors were picking up a lot of subcontracting work including laying pipes for the Awapuni industrial separation and minor pipelines serving the grape processing industries.

“Extensive use is also being made of local subcontractors on the Banks Street building site for precast panel erection, internal structural steel fabrication and erection, fabrication and installation of steel pipework, fabrication and erection of light steel components and general machinery hire.”