High levels of ammonia in the Yamuna disrupted water production and supply in parts of Delhi on Thursday before being restored on Friday.
According to the Delhi Jal Board (DJB), the ammonia level in the water was around 5.8 parts per million (ppm). As a result, water production decreased at the Chandrawal, Okhla and Wazirabad water treatment plants (WTPs), which draw water from the river.
A DJB communication said on Thursday that water supply will be disrupted in areas including South Delhi, Civil Lines, Kamla Nagar and adjoining areas, Sangam Vihar, New Delhi Municipal Council and Patel Nagar on Thursday evening. , And on Friday morning. By Friday afternoon, the water production reached the normal level.
DJB’s water treatment plants can treat ammonia up to a level of 1 ppm. Chlorine is used to remove small amounts of ammonia from raw water, but the compounds formed by adding excess chlorine can be harmful. The BIS standard for ammonia in drinking water is 0.5 ppm. The release of industrial waste and organic waste into the river can lead to an increase in ammonia levels.
A DJB official said that releasing water from Wazirabad can help in reducing the ammonia level and help reduce it to the concentration that can be treated by the plants.
According to another DJB official, technology is being upgraded at Chandrawal and Wazirabad WTPs to treat high levels of ammonia. The newly installed technology is expected to treat ammonia levels up to 4 ppm.
At Chandrawal WTP, ozonation, which includes treatment of ammonia using ozone, will be used, and the system is being installed, he said. He said that consultancy work is underway for a new plant at Wazirabad and technology is being worked out for treatment of ammonia levels in water.
The plant capacity at Chandrawal is 90 MGD, while the one at Wazirabad has a capacity of 120 MGD.
A government official said the upcoming Chandrawal plant will also have aerated biological filters that can help remove ammonia with the help of bacteria.