Officials said over the last five years, 32 sewage treatment plants (STP) with additional treatment capacity of 554 million litres per day (MLD) were made operational to treat wastewater, as the level of biochemical oxygen demand (BOD) of the state’s entire Ganga stretch has come down below 3 mg/L, as per data available with the govt. “This is a significant improvement compared to 2018 and 2022, when BOD levels were recorded at 12 mg/L and 8 mg/L respectively,” said an official.Since April 2025, four STPs at Maheshtala in South 24 Parganas, Raghunathganj and Jangipur in Murshidabad, and North Barrackpore in North 24 Parganas were put under trial run, and they are now functional. “The entire stretch of the Hooghly rom Farakka to Diamond Harbour, covering nine districts along the river bank, has been upgraded to the least polluted category,” officials said.Officials said that to reduce faecal coliform levels in the river, septage is being co-treated at functional STPs that are being set up across riverside towns. A 125 KLD functional STP at the regional wastewater management centre in Baidyabati, Hooghly, was recently made operational to treat septage from nearby six municipalities of Uttarpara-Kotrung, Konnagar, Serampore, Rishra, Champdani and Baidyabati. “The facility may further reduce faecal coliform levels in the Ganga,” said an official. The rising dolphin population is promoting tourism and enhancing local livelihood,” said a senior govt official.
