Filter cover at Bromley plant for odour tests

Press, 3 November 1983, Page 9

Filter cover at Bromley plant for odour tests

Bromley residents will very soon have a visible sign to assure them that something is being done to stop the sewage odours that have plagued them for years. Christchurch Drainage Board staff will be working from early this morning to erect a huge bright blue “umbrella” over one of the filters at the Bromley treatment works.

The $20,000 filter cover is a trial which, if it proves successful, will finally put an end to the works’ odour problem. The tent-like structure would trap air to enable the board to test a new wet oxidation process expected to be installed early next year, said the chief engineer, Mr H. P. Hunt, at a meeting of the operations and services committee yesterday. “We are reasonably hopeful that this plant will dissolve the odorous components,” said Mr Hunt. The tent would also help the board staff find out how the filter would cope with a cover.

“We do not know how the filter will react — it has always had as much oxygen as it needs,” he said.

If all goes well, it will be replaced with a permanent

dome, and a full-scale treatment process would be working by the end of 1985. The trial dome will allow a final decision on how much air needs to be pumped through the eventual plant. “It may be that the pumps we require do not need to be as large as what is planned at the moment,” said Mr Hunt.

The wet-oxidation plant which will arrive from Britain in January will cost the board about $145,000 and the final plant has been estimated about $1 million. Wildlife disturbed Sumner residents are concerned about effluent and stormwater which are being discharged over the Scarborough cliff into a wildlife refuge. The Residents’ Association has written to the board, saying that nesting birds are being washed off ledges at times of heavy rainfall by water cascading from outlet pipes over the cliff face. This has resulted in the loss of eggs and chicks. They are also concerned about the poor quality of the effluent discharged in the area.

Mr. Hunt said that the

staff was aware of the nuisance caused by septic tank failures in the area, but owners whose propeties were more than 60 metres away from sewers were not required by law to connect their houses to the main lines.

At the most, the board could only attempt to persuade the owners to connect with the sewers.

The discharge on to the board sanctuary was not great compared with the new Scarbourgh walkway drainage channel. The committee decided to advise the residents of these points. Legal action? The board will seek legal advice on the possible prosecution of Caltex Oil (New Zealand), Ltd, after 250 litres of diesel was discharged into stormwater systems in central Christchurch.

Mr Hunt waid that on or about October 12 the oil was discharged from a tank vent pipe at the rear of the Savoy Theatre in Press Lane.

Only a siphon arangement in the stormwater system [>revented considerable polution' of the Avon river, he said.