Mumbai generates about 2,800 million litres of sewage daily, an official guesstimate. Experts believe the quantity is much higher, and remains unaccounted for. But what is the jewel in the sewage crown? Dumping untreated sewage into the sea. This operation masquerades as ‘marine outfall’. “Marine outfall is a state-of-the-art system, which disposes of sewage three kilometres inside the sea through a pipeline running along the seabed. Sewage is dispersed at various points inside the sea for minimal pollution. These marine outfalls are capable of discharging sewage even during a high tide and their pumping capacity is five times the normal sewage flow,” says D T Dange, chief engineer (sewage operation), mcgm.
mcgm has divided Mumbai into seven sewerage zones (see table and map: Solid waste). The sewerage network, over 1,400 km, comprises 41 satellite pumping stations and seven major pumping stations