Kaiapoi Council Seeks Talks On Pollution

Press, Volume CIX, Issue 31975, 30 April 1969, Page 4

Kaiapoi Council Seeks Talks On Pollution

The North Canterbury Catchment Board lacked understanding of the efforts of the Kaiapoi Borough Council to combat pollution in the Kaiapoi River, said Cr R. L. Wylie, chairman of the town planning and by-laws committee, at the monthly meeting of the council last evening.

Heated discussion was caused by a newspaper report of a board meeting at which it was decided to ensure that Unilever (N.Z.) Ltd, did not discharge polluted effluents direct into the Waimakarlri River from its proposed factory at Kaiapoi. The board had agreed that if the company built a factory: it would have to provide fori the discharge of effluent into the south branch on the north side. The effluent woud then flow into the Kaiapoi River and would not reach the Waimakariri until it was almost out to sea. The board said it wanted to pre-: serve a popular swimihingl spot in the Waimakariri I which would be affected if effluent went into the river! direct from the company’s factory. Cr Wylie said that the council planned to spend $122,300 to improve sewage treatment facilities, enlarge the works, and remove the pollution problem when discharging into the river almost opposite the south branch entry’ point. “The Catchment Board is now agent for the Water Pol- i lution Council for all waters in the area and it is very) important we should be work-’ ing together, not apart,” he said. “The Waimakariri is polluted and not suitable for swimming. All councillors are aware of the amount of pollution entering the south branch. Anything more and it will come into Kaiapoi on the incoming tide. Kaiapoi pressed for the classification of the river, the first in the South Island." i Cr J. McKenzie said that the Waimakariri was ruined on one side. It was very wide and fast-flowing, but if tbe proposal was allowed the rest would also be ruined quickly. The Mayor (Mr H. O. Hills) 'said that the council was required to purify effluent from the proposed sewerage ■scheme. “In putting our own house in order we definitely expect others to conform as well,” he said. i It was decided that the I catchment board would be incited to discuss river pollution in the Kaiapoi area with ithe council. | Cr Wylie said that he was

not against industry and be understood that a different company was now involved with proposals at the same site. Sewerage Scheme The proposed sewerage development scheme provides facilities for the increasing population of the urban area by improved treatment to minimise pollution of the Kaiapoi and Waimakariri Rivers; the provision for an area south of Kaiapoi where urban development is expected; and the rearrangement of outfalls for parts of the existing sewered area to provide for increased population within that area. It includes 818 acres in the existing borough plus part of the Eyre County known as the Riseley block, 90 acres, ifrom which sewerage is ; already pumped to the borough's system and 358 acres of expected future extensions south to the Waimakariri, between State Highway 1 and the Northern Motorway—a total of 1266 acres.

The consulting engineers report says that because of the uncertainty in estimating population growth, treatment works are designed for 15 years with provision for extensions when required. Population estimates are:

1971, 4730; 1986, 9000; 2001, 13,000.

the engineer recommends oxidation ponds as now “wellproved for the treatment of raw sewage and requiring very little maintenance if properly built." These would be sited on a Kaiapoi council plantation reserve about half a mile east of the borough boundary. “It has been suggested that the Kairaki and Pines Beach settlements in the Rangiora County should be served by the Kaiapoi treatment works and this has been allowed for in the design. The holiday population is estimated as 1970, 1600: 1985, 1900; 2000, 2200. A 50 per cent overload may be used in designing treatment for the holiday population, says the report. The present Imhoff tank gives only primary treatment and discharges into the Kaiapoi River near the populated area. To improve the effluent would require biological filters which would be most undesirable on the present site, says the report. The Kaiapoi and Waimakariri Rivers are classified D under the Water Pollution Regulations, 1963, except for the lower reaches used for recreational purposes, which are class C. Because of the class C water a high degree of treatment is needed, such as could be provided by oxidation ponds. The existing system of sewers and pumps was designed in 1951 for the area within the borough boundary to an ultimate population, considered then, of 4300.

Since then the Riseley block has added 90 acres and it is estimated that by 1971 the population served by the system will be 4730. While! the sewers are adequate,; shortly the pumps will be over-loaded and it will be necessary to provide a new pumping station near Ohoka Road to serve new areas to! the south of the borough. The programme is planned in two stages, the second delayed for some years to suit population growth. Stage I, including the treatment works and sewage conveyance facilities, is estimated at $122,300, and stage II another $53,500. The report’s conclusion is that these works would provide a modem system of sewage disposal with low maintenance costs and capable of extension to serve the district for the foreseeable future. The existing system would be rearranged to permit population expansion within the existing borough boundary and stage II would provide for extension to the south. No particular engineering difficulties are expected in this scheme, the report says.