High levels of ammonia in Yamuna water: The cause, effect and possible solution
30th July, 2020
Context:
The Delhi Jal Board (DJB) had to reduce water production capacity by 25 per cent after high levels of ammonia were detected in the Yamuna River.
The acceptable maximum limit of ammonia in drinking water, as per the Bureau of Indian Standards, is 0.5 ppm.
Delhi was recording 3 ppm.
Ammonia and its effects:
Ammonia is a colorless gas and is used as an industrial chemical in the production of fertilizers, plastics, synthetic fibers, dyes and other products.
Ammonia occurs naturally in the environment from the breakdown of organic waste matter.
If the concentration of ammonia in water is above 1 ppm it is toxic to fishes.
In humans, long term ingestion of water having ammonia levels of 1 ppm or above may cause damage to internal organs.
Entering in Yamuna:
The most likely source is believed to be effluents from dye units, distilleries and other factories in Panipat and Sonepat districts in Haryana.
Sewage from some unsewered colonies in this stretch of the river.
Treatment of Ammonia:
The DJB at present does not have any specific technology to treat ammonia.
The only solution it adapts is to reduce production at three water treatment plants — Wazirabad, Chandrawal and Okhla — which are largely affected by the pollutant.
The board mixes raw water that carries high concentration of ammonia with fresh supply from Munak canal.
The amount of chlorine added to disinfect raw water is also increased when high levels of ammonia are detected.
Long Term Solution:
Stringent implementation of guidelines against dumping harmful waste into the river,
Making sure untreated sewage does not enter the water
Maintain a sustainable minimum flow, called the ecological flow.
The lack of a minimum ecological flow also means accumulation of other pollutants.