High levels of ammonia in Yamuna water: The cause, effect and possible solution

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.

Reference: https://indianexpress.com/article/explained/high-levels-of-ammonia-in-yamuna-water-6527247/