Delhi govt plans to identify pollution hotspots responsible for frothing in Yamuna river

New Delhi: The Delhi government will conduct a study to identify pollution hotspots, including colonies and industrial areas, responsible for frothing in the Yamuna river, officials have said.

The study also aims to form short and long-term action plans for minimising foaming in the river, they said.

According to the project proposal, the environment department's study will ascertain the sources and reasons behind the froth in the river which reflects the "deadness of the water and nil (level of) dissolved oxygen in it".

Frothing in certain stretches of the river, such as near ITO and the Okhla Barrage, has become an annual phenomenon in winters when the temperatures are low and flow in the river is less.

According to officials, the primary reason behind the formation of the toxic foam is the high phosphate content in the wastewater. Detergents used in dyeing industries, dhobi ghats and households are the major sources of phosphate, they said.

"Wastewater from authorised colonies and settlements with high phosphate content reach the river through untapped drains. When water falls from a height at a barrage, the turbulence agitates the phosphoric compounds in the river which leads to the formation of froth," an official said.

Experts say the problem of frothing will continue unless sewage treatment plants and common effluent treatment plants in Delhi are upgraded to meet the new standards and all unauthorised colonies are connected to the sewer network.

Delhi generates around 770 MGD of wastewater. The 34 sewage treatment plants at 20 locations across Delhi treat up to 570 MGD of sewage. The rest empties into the river directly. Government data shows that only eight of the 34 operational sewage treatment plants in Delhi meet the prescribed standards for wastewater (BOD and TSS less than 10 mg per litre). Together, they can treat 150 million gallons of wastewater a day.

The study will identify major drains accounting for maximum pollution in the Yamuna river and hotspots, including colonies and industrial areas.

It will also assess and identify sources of froth in the Najafgarh drain and the supplementary drain, according to the proposal.