As a result, 100 million litres per day of additional water will be treated, reducing the need for withdrawing water from lakes and reservoirs.

On Thursday, the Brihanmumbai Municipal Corporation (BMC) awarded the tender and signed the Memorandum of Understanding for the design, construction and operation of the 990 MLD treatment plan under the Middle Vaitarna Project with French company Degremont Suez, which had set up the existing 1910 MLD water treatment plant at Bhandup in 1980.

Degremont Suez Chief Executive Officer Thierry Mallet said the company was using international and advanced machinery for the treatment and filtration of water. “The quality of water in Mumbai is good and will be better after treatment at the new Bhandup plant,” Mallet said.

Deputy Municipal Commissioner (Special Engineering) Pramod Charankar said that concentrated sludge from the Middle Vaitarna Dam mainly contained soil. “Water and mud will be separated in a centrifuge and water will be cycled back for treatment through filter backwash and sludge clarifier,” Charankar said. Till now this water was discarded but “now there will be zero loss of water plus we will get additional water up to 100 MLD”, he said.

Thierry said it would be for the first time the sludge process will be carried out in Mumbai.

Though the BMC has initiated its Mumbai Sewage Disposal Project under the Centre’s Jawaharlal Nehru National Urban Renewal Mission where sewerage will be treated before being discharged in the sea, Mallet said there was a need for advanced waste water treatment plant.

“Mumbai has primary waste water treatment plants where biological method can be used to remove suspended particles by growing bacteria and then treating the sludge in a biogas recovery plant,” Mallet said, explaining the Delhi model which can be adopted in the city too. The company was awarded the Rs 1.5-billion project by the Delhi Jal Board recently for treating 1.36 lakh cubic metres waste water per day.

The French company, a pioneer in de-salination technology, said that the option was looking increasingly attractive and should be explored. “There are projects in Spain, Perth and even Chennai on de-salination but the cost is more. Mumbai should definitely explore this option after a few years,” Mallet added.