Context:
The recent rise in ammonia levels in the Yamuna has highlighted the recurring issue of pollution, causing disruptions in the supply of drinking water.
- The ammonia levels have reached around 5 ppm (parts per million), surpassing the filtration capacity of Delhi’s water treatment plants.
- High levels of ammonia mean large amounts of untreated industrial chemicals and sewage entering the river and polluting the raw water supply chain.
About Ammonia
- Ammonia is a colorless, gaseous chemical with a sharp odor, easily dissolvable in water.
- It is used in industrial processes, fertilizers, coolants, cleansing agents, food additives, animal feed, and plastic/paper manufacturing according to WHO.
- Major sources of ammonia pollution include runoff from farmlands, industrial effluent discharge, untreated sewage, and degradation of organic matter (e.g., blue-green algae).
- Long-term exposure to ammonia can damage internal organs due to its corrosive properties (US Department of Health and Human Services).
Solutions for Yamuna Pollution and Water Management
- Ozone-Based Treatment: Ammonia removal involves using ozone as an oxidant to chemically convert ammonia (NH3) into nitrogen gas (N2) and water (H2O), It can handle ammonia levels up to 4 ppm.
- Chlorification of water: To neutralize one ppm of ammonical nitrogen, 11.5 kg of chlorine is needed per liter of water per hour, and some chlorine must remain in the treated water to neutralize pathogens.
- Pollution Reduction: Long-term solutions include installing proper sewage treatment plants at the source and preventing the mixing of drains.
- Infrastructure Enhancements: A conduit pipeline should be laid to separate potable water from sewage. The Yamuna Monitoring Committee suggests fast-tracking approvals for this.
- Ecological Flow: Maintaining a sustainable minimum water flow is critical for ecosystems and human livelihoods. The Yamuna Monitoring Committee has recommended revising the 1994 water-sharing pact to increase freshwater release into the river.
- Ammonia Sensor Installation: Install an ammonia sensor (e.g., Xylem WTW) on the riverbank to monitor ammoniacal nitrogen (NH4-N) levels.
- Flow Meter and Alerts: Install a flow meter with alerts to ensure regular water levels at new locations.
- Sludge Management: Sludge accumulation in the riverbed can generate ammonia. Regular desludging will help manage this.
- WTP Upgrade: The Delhi Jal Board should explore upgrading existing water treatment plants (WTPs) to handle increased ammonia levels through enhanced purification processes.
- Environmentalists recommend maintaining a sustainable minimum flow, known as the ecological flow, to support ecosystems and human livelihoods.