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Manual scavenging no more: IIT students develop robot to clean septic tanks and sewers

A ‘scavenger’ robot developed by students at IIT-Madras uses high-velocity cutters to cut through the thick sludge in septic tanks, after which the debris can be scooped out with a vacuum pump. The robot is priced between Rs 10 and Rs 30 lakh.

Manual scavenging was abolished in 1993, and the ban was again reinforced in 2013. Yet, it continues. In fact, according to a 2018 report by the National Commission for Safai Karamcharis (NCSK), one person loses their life every five days while cleaning sewers and septic tanks across the country. 

Even as states look to deploy mechanised systems to clean sewers and septic tanks, these are yet to be universally implemented. The Delhi government recently inducted 200 mechanised systems to clean sewage, but each one came at a hefty price tag of Rs 40 lakh. 

Now, students at IIT-Madras have come up with a feasible sanitation solution, priced between Rs 10 lakh and Rs 30 lakh. The Sepoy Septic Tank Robot uses high-velocity cutters to cut through the thick sludge in septic tanks and clear drains. Once the sludge is cut through, it is sucked out using a vacuum pump, according to a Financial Express report.

Talking to The Hindu Dr Prabhu Rajagopal, from the Centre for Non-Destructive Evaluation at IIT-Madras and who has been working on the project for about four years, said,

“To move in the fluid, a robot needs to have a propeller, but the conditions in a septic tank pose specific problems. If you use a rotary propeller, like in an aircraft, the blades will get congested.”

To overcome this, the team used bio-inspired fins, and developed a six-fin propeller led by Srikanth, a masters’ student at the institute.

Dr Rajagopal said, “The propeller is retracted and put into the septic tank. It then opens up and we rotate it, and the contents of the septic tank are cut up. They can be sucked out using vacuum pumps,” reports The Hindu.