Hoping to get Mumbai's rivers cleaned up, the civic body will conduct a survey to find out how many sewerage lines are discharging untreated waste water into them.
The survey will help the Brihanmumbai Municipal Corporation (BMC) gauge the amount of polluting sewage being discharged into the rivers every day.
The civic body has found several street connections – drainage pipelines of residential and commercial establishments – across the city are connected to storm water drain pipes instead of sewerage lines. This is resulting in untreated waste entering the rivers or the sea, as effluents from only the sewerage pipes are sent for treatment.
This is responsible for the city’s rivers like Mithi, Oshiwara, Poisar and Dahisar, increasingly resembling nullahs. The data the BMC has about its sewers is decades-old.
Hence, the civic body has appointed contractors and will spend Rs36.13 crore on a GIS-based survey of street connections. The survey will begin in October and is expected to be completed in two years. It will provide the BMC updated figures on the amount of sewerage the city generates, and help it plan treatment strategies.
Recently, a water quality test conducted in Dahisar showed shocking results, such as the presence of sewerage in the river and a high acidity level of the water. The condition of Mithi, Oshiwara and Poisar is no better.
“Once we have the exact data on street connections linked to drains, we can prepare a plan for diversion or treatment of such connections. This will reduce the pollution in the rivers,” said Vipin Kumar Pandey, chief engineer of the sewerage operations (SO) department.
The cases of sewerage lines connected to drains were found in Grant Road, Dockyard Road, Juhu, among others. “Recently, we have found many cases of sewerage lines of residential or commercial buildings connected to storm water drains. This is illegal, as these drains are supposed to carry only rain water or non-potable water,” said a senior official from the SO department.