NEW DELHI: Visuals of toxic froth floating on the surface of the Yamuna river near Kalindi Kunj in Delhi made their way back to social media over the past few days, with experts citing detergents as one of the major reasons behind the pollution.
A majority of the detergents in the country don't have a certification by the ISO (International Organization for Standardization), which has capped the concentration of phosphates in the chemical substance, an official of the Central Pollution Control Board (CPCB) said.
The primary reason behind the formation of the toxic foam was high phosphate content in the wastewater because of detergents used in dyeing industries, dhobi ghats and households, according to the official.
"A large number of unbranded detergents are also used in households and dyeing industries. The wastewater containing high phosphate content reach the river through untapped drains," he said.
These detergents and other organic matter gets deposited in the riverbed when the river is flowing normally. When more water is released upstream, it falls from a height on reaching the Okhla Barrage, leading to turbulence and churning which causes froth.
The solution is that every household is connected to the sewer network and treatment of the wastewater, he said.
"If 100 per cent of the wastewater is treated, there will be no such problem at all. The capacities of STPs (sewage treatment plants) are underutilised and the standards are not met," the CPCB official said.
Another reason, but not a major one, for the frothing is the release of certain gases when a specific kind of bacteria become active in anaerobic conditions -- when there is no or little oxygen is available.