The final answer for city wastewater may be an ocean outfall, but whatever the City Council decides, it is not having to start its planning from scratch.

The process which led to the Council deciding to support a strategy of cleaning up the wastewater as much as possible and then releasing it into the estuary included many investigations of other possible systems.

Those investigations will now help in the search for an estuary outfall alternative.

In August 1999, the Council short-listed the estuary and a direct ocean pipeline as options to be compared and evaluated in detail. Before that decision was taken, staff and outside experts had also looked at reusing treated wastewater as drinking water, treating household waste in the home and reusing greywater, using smaller local treatment plants, disposing of wastewater on land and at the estuary mouth, aquaculture (using the east Christchurch ponds to grow fish) and various options to cut down over time the amount of wastewater being produced by the city.

The Council went with the estuary plan rather than an ocean outfall because it wanted to put its main effort into improving the quality of treatment, rather than on where it was ultimately going.

In making the decision, it said that the wastewater, “should be treated to such a degree that its discharge into the environment should have impacts so low that the method of discharge becomes a relatively minor consideration”.

It was the Council’s aim to make sure the wastewater coming out of its treatment system was well above the minimum standards, so that the estuary would be suitable for recreation activities in all places at all times.

The estuary option was seen to fit with the Council idea of sustainability – in this case turning the “problem” of waste into a valuable resource and as an opportunity to develop a recreational and ecological asset. The main planks of the Council’s wastewater strategy are to reduce, reuse and recycle. At the time the decision was made, was thought an ocean pipeline would reduce the effort put into this area.

Other reasons for the Council opting for the estuary option were that the plan was designed to be flexible and that it was considered to be the most economic one which would meet the quality standards it has set.