A new method called Soil Biotechnolgy(SBT), developed by IIT, Mumbai, is being used for sewage treatment at Lajpat Nagar, New Delhi.
All the plastic and solid waste is removed from the sewage as it passes throgh a mesh on the top of a tank. "The tank has a bio-reactor containing microbes and natural additives that purify the water by removing odour, colour and bacteria.
Above this tank, there is an evergreen garden with some native species of plants that serve as biological indicators. The water flows into a collection tank where it is pumped for irrigation." Said Rajesh Jain managing director of Enhanced WAPP Systems (India)
Private Limited, the company that set up and is at present maintaining the plant for DTTDC.
The entire purification process takes place underfround and it removes 99% of the bacteria in the sewage, he added.
The technology is also being used in Taj Hotel, Gwalior, ITC Mughal Sheraton, Agra and Vazir Sultan Tobacco Industries in Hyderabad.
"Another advantage is that the plant uses very little electricity, except when water has to be pumped for drip irrigation or sprinkling," said Ashok Khurana, the superintending engineer of the plant.