Raw sewage discharge will stop soon

Press, 17 December 1988, Page 9

Raw sewage discharge will stop soon

Raw sewage discharge into the sea off Diamond Harbour will soon cease as the Lyttelton Borough Council forges ahead with a $725,000 sewage treatment plant at Pauaohinekotau Head.

Work on the plant began this week, the tender for stage one of the contract going to Husband Construction, Ltd. The new plant will have raw sewage channelled from the present Stoddart Point outfall to an existing treatment plant, known as the Dorr Oliver site, at Pauaohinekotau Head. The work has to be completed by April, 1990, to comply with the North Canterbury Catchment Board's restrictions on water rights to the two outfalls, which expire at that date. Stage two of the work has not yet been let as tenders are still being received. Stage one of the plan will include the upgrading of the Dorr Oliver site to enable it to receive effluent from Stoddart Point. The area will be extended and new concrete tanks constructed. A pumping station at Stoddart Point will be built during the second stage to pump the untreated sewage to the site for treatment and dis-

charge. Plans to clean up the outfall at Stoddart Point have been in the pipeline for several years. The council’s chief engineer, Mr John Christensen, said the discharge of raw sewage into the harbour was unsatisfactory. Pressure from increasing residential development in Diamond Harbour had reinforced the need for a sizable treatment plant to accommodate the new subdivisions. A report, commissioned by the council in 1984, to investigate and provide a plant for Lyttelton, Diamond Harbour and Cass Bay sewerage reticulation, recommended that Diamond Harbour receive priority attention for the raw and treated sewage outfalls. A follow-up report in 1987 investigated options for the Diamond Harbour area only. In a survey conducted by the consultants it was found that a discharge off Stoddart Point would most likely have an impact on the foreshore and

Diamond Harbour during flood tides. The report said a similar discharge off the Dorr Oliver site would have a negligible impact on recreational and fishery resources. The withdrawal of Government subsidies in May, 1986, has been responsible in part for the council struggling financially to keep up with its programme. However, the council has been committed to treatment and discharge works. Cass Bay was connected to the Lyttelton system several months ago, and the outfall at Stoddart Point will be channelled to Pauaohinekotau Head, by 1990. The only remaining raw sewage outfall is at Sticking Point, the borough’s main outfall. A research officer with the North Canterbury Catchment Board, Mr Ken Taylor, said as far as the board was concerned no raw sewage was acceptable in enclosed coastal waters.