Muck in Chennai rivers may soon turn manure

CHENNAI: Government agencies is trying to make the most out of muck. Scientists from Bhabha Atomic Research Centre (BARC) on Tuesday met government agencies in the city to introduce a technology that can convert sewage into organic manure.

Sewage being illegally let out into the Adyar and Cooum rivers has been an impeding problem to cleaning up the water bodies. Now, Chennai Corporation, Metro water, the state public works department and Chennai Rivers Restoration Trust (CRRT) are planning to reverse this, and have some use with the byproduct.

Once the sewage or sludge is dredged out of these rivers, a process called hygienisation will convert the waste into organic manure. It has been done before: A sewage sludge hygienisation cacility set up by the Vadodara Municipal Corporation is operational in Gujarat. Ahmedabad is setting up one such plant, and Nagpur is likely to follow suit.

The process involves exposing the sewage to gamma radiation that kills the pathogens. "It will look like an airport conveyor belt where sewage in boxes goes through a round of gamma irradiation and comes out pathogen-free," says BARC's senior scientist, technical coordination wing, Daniel Chellappa. "About 99% of sewage is in liquid form and less than 1% of it is solid/ dry. But it is the dry component that is rich in organic content. After hygienisation the dry part can be used as manure or as a bio-fertiliser by adding nutrients to it."

A 100mld plant can generate ample manure, and will require an investment of Rs10 crore to Rs15 crore. The manure can be used in public parks or given to farmers. A kilogram of bio-fertiliser fetches Rs20 to Rs50. "We are going to discuss the feasibility details of this technology," said a corporation official.