The Infrastructure Department has now put in a planning application for the new plant, which will replace its 60-year-old predecessor, at a cost of up to £75m.
Infrastructure argues that the current plant has become inefficient and fails to meet the required nitrogen discharge standards – potentially a reason for the sea lettuce problem in St Aubin’s Bay.
They say it has also become too costly to repair and is not suitable for expansion. It was built for a population of 57,000, a little over half the current number. The new plant is intended to cope with population growth, based on a prediction of 118,000 in 2035.
The new plant should also see the costs of operation and maintenance reduced by 30%, and do better when storms flood the current system, leading to discharge into the sea.
Preliminary works have already started with the relocation of the Household Recycling Centre to La Collette and the excavation and stabilisation of the hillside. This work is due to be completed by the end of the year.
If the planning application is approved, construction of the new plant should start at Spring 2018, with completion scheduled for mid-2022.