Frothing in Delhi’s Yamuna

Subject – Environment

Context – layer of froth was seen floating over parts of the Yamuna river near Kalindi Kunj

Concept –

The froth is a sign of a polluted river.
Experts say the release of untreated or poorly treated effluents, including sewage from those parts of the city that are not connected to the sewerage network and industrial waste, could lead to frothing.
Specifically, phosphates in the river form the froth.
- Surfactants and phosphates from detergents in households and industrial laundry find their way into the river, as all the sewage is not treated.
The river is in a lean phase and the water flow is less. Pollutants, therefore, are not diluted.
The water falling after discharge from the Okhla barrage causes the surfactants and foaming agents present in the wastewater or in the sludge on the river bed to get agitated, forming foam.

Okhla barrage

It is a roughly 800-yard long weir across Yamuna River opened in 1874.
It also serves as the location of Okhla Bird Sanctuary today.
It is situated 10 km to the south of New Delhi and downstream of Nizamuddin Bridge at Okhla, where Agra canal originates from it.
The top of barrage also serves as the Delhi-Noida carriageway of Mahamaya-Kalindi Kunj road.
It is under the management of the government of Uttar Pradesh.