A ‘drain’ water harvesting plant, capable of treating around 4 million gallons of sewage water per day, has been constructed as a pilot project near the Akshardham temple by technicians associated with the Delhi Jal Board (DJB).
The plant was set up in collaboration with water treatment supplier Alcantarilla Limpiar Equipo Private Ltd a month ago. “Delhi Development Authority (DDA) officials visited this plant… DJB officials are enthused about it. If implemented across Delhi, it can treat 700 million gallons of water per day,” said Abhisek Bhattacharya, a Delhi Legislative fellow working with DJB and part of the project.
As part of the process, the drain water is made to go through an electrocoagulation reactor, which removes iron sludge from the water. A chemical coagulant is added to it, which makes the solid pollutants settle at the bottom. The cleaner water from the surface is then skimmed and allowed to sit in a tank where oxygen supply is reduced to kill harmful bacteria. The water is then passed through activated carbon and multi-grade filters. Treating it with UV rays and reverse osmosis makes it fit for ground-water recharge and drinking purposes respectively.
“It takes Rs 45-50 to treat a kilolitre of water with this plant… the process is cheaper by 50 per cent than that done through conventional treatment plants. The total dissolved solids (TDS) in drain water is more than 400… With this process, we have brought it down to 70…,” said Bhattacharya.