A project to replenish the water table using treated sewage water was launched as an experiment today by the Water Services Corporation.

CEO Mark Muscat said the project was aimed at starting a process to recharge the aquifer in order to reverse its depletion after years of over-pumping through legal and illegal bore holes - causing the quality of the remaining water to deteriorate.

Water from Sant Antnin sewage purification plant is being pumped to Bulebel where a small water filtration unit treats it further and takes away most of its impurities.

The water then goes through reverse osmosis and is pumped underground and allowed to filter through the rocks to the water table, a slow process which thus provides for further filtering. The experimental unit can handle up to 11 cubic metres of water a day.

Mr Muscat said that the plan is to eventually have such units linked to the sewage treatment plants in Gozo and at Ic-Cumnija, Mellieha, so that the waste water would actually not be wasted.

But it will not be cheap. The process will cost some 54c per cubic metre and the cost of equipment for the two sewage treatment plants would be in the region of €28 million. They can produce 60,000 cubic metres of treated water daily.

However, pumping of water from the aquifer is far cheaper than producing water from RO plants.