Final breakthrough on the 5.8 km Borivali–Malad sewage tunnel; project 90% complete

Mumbai: The municipal corporation's Priority Sewer Tunnel Phase-1 project, meant to relieve the overloaded sewers of the western suburbs, reached a milestone on Friday. The 5.8 km underground tunnel between the Don Bosco School junction in Borivali and the new Malad pumping station at Malvani made its final breakthrough at the Don Bosco end. The project is 90% complete and is due to be finished by July 31, 2027.

The tunnel was bored from the Malad pumping station towards Borivali using segmental lining. It has an internal diameter of 3.2 metres and can carry 1,182 million litres of sewage a day. The project includes five shafts, three drop shafts and six screen chambers.

The existing sewers of Dahisar, Borivali, Gorai, Charkop, Malad and Kandivali, in the R South, R Central and R North wards and part of P North, cannot cope with the volume of sewage and run overloaded. The tunnel will raise sewage-carrying capacity for Dahisar, Borivali, Gorai, Shimpoli and Charkop to 1,136 million litres a day.

Sewage now sent to the Gorai, Shimpoli, Charkop and Malad pumping stations will flow straight into the tunnel, so those four stations will no longer be needed, saving on their upkeep. The project, run by the civic body's Mumbai Sewage Disposal Project department, aims to improve the quality of water released into the sea and rivers and reduce pollution.

Sources: Loksatta; NavShakti