Strainers that trap plastic items, fallen leaves and other solid waste will be placed in gully pits to prevent them from clogging, a senior official of the Kolkata Municipal Corporation (KMC) said on Wednesday.
The strainers will be fitted under the concrete cover of the gully pits in a few pockets of the city initially as part of a pilot project.
The Telegraph had earlier reported that fallen leaves, twigs, broken branches of trees and plastic bags block the mouth of many gully pits across the city, thus preventing the flow of water accumulated on roads into underground sewers and causing waterlogging.
A senior official of the KMC said solid waste entered sewer lines through gully pits and blocked the flow of water through the conduits.
Some of them end up in the strainers fitted in the drainage pumping stations, where the water reaches through the sewers before being pumped into canals.
The presence of solid waste in the sewer network is a significant obstacle to tackling waterlogging, a problem that paralyses large parts of the city every monsoon.
“We have procured six stainless steel strainers. They have micro openings through which water or other liquid will enter the pit. But solid waste will get trapped in the strainer. Our people will clean the strainers at regular intervals,” said the senior official.
The KMC plans to fit the strainers in six locations next week or the week after.
The performance of the strainers will be observed for some time to check for any operational difficulties.
“This is a pilot project. We do not know if there will be any challenges. We have to see whether water flows into the pit freely despite solid waste getting trapped in the strainers. There is also a fear that the strainers could be stolen at night. We have asked the contractor to see if there could be any locking system,” said the senior official.
Each of the strainers procured by the KMC costs around Rs 7,500.
“The gully pits in the city are of various sizes. The cost of strainers for smaller gully pits will be lesser,” said the official.
The city has about 2 lakh gully pits.
The official said that if the six strainers that would be installed during the pilot project were found to be working properly, more gully pits would be fitted with such filters.
The KMC’s decision to install strainers to prevent clogging of sewer lines shows how big a problem plastic and other plastic products pose.
Many canal banks in the city are covered with plastic and other waste, which finally slips into the water and block the flow, KMC officials said.