It has been 40 years since Christchurch’s wastewater treatment plant was officially opened. The plant was built by the Christchurch Drainage Board over six years and cost about £1.35 million.

The Drainage Board was set up in 1875, with responsibility for all the local body areas that eventually came under the Christchurch City Council at amalgamation. It went out of existence in 1989 when its responsibilities passed to the City Council.

It was rapid population growth and housing development in the city after World War 2 which pointed up the need for a modern treatment plant and planners had growth in mind when it was being designed. At its opening in late October 1962, the plant was designed to cope with the expected wastewater from a population of about 500,000.

Mr J.T. Noorgard, the San Francisco engineer representing the plant’s design firm, reminded the Drainage Board members in 1962 that although the plant was as good as any in the world, upgrades and improvements should be expected over the years. “We may sometimes forget that a plant of this nature is never complete,” he said.

Improvements have been almost continual since that time. This summer City Council staff are working on deepening and reshaping one of the plant’s oxidation ponds to increase the ability of sunlight to kill bugs in the water and so improve the quality of the wastewater before it is discharged.

That work is part of an upgrade which began in 1997. The aim is to further improve the quality of wastewater discharged from the plant and to make sure it will be able to cope with expected growth in the city’s population and industry.

On Wednesday, 6 November, at midday past staff will gather at the treatment plant in Shuttle Drive. There is also be a display of photographs and other material about the history of the plant. Reporters and photographers are welcome to attend.