SEPoy – a Septic Tank Cleaning Robot

Efforts have been evident time and again from both the government and the non-profit development sector to curb this obsolete practice. Rehabilitation and skill-based employment opportunities have been doled out to keep them engaged in alternative professions.

Recently, a team of IIT-Madras students has found a tech-based solution to the menace. Final year student Divanshu Kumar and his team invented SEPoy – a Septic Tank Cleaning Robot which has the potential to eradicate manual scavenging altogether. Guided by Dr Prabhu Rajgopal, an expert in this domain, the team has developed an advanced design which enables the robot to “cut and homogenize sludge in Septic Tanks so that it can be sucked off using vacuum pumps,” as mentioned in its technical description. The machine, if commercially manufactured, can cost between Rs 10 lakh to Rs 30 lakh, depending on specialisations installed.

Meeting with manual scavengers

“Dr Rajagopal has been involved in this project for over four years. In fact, a precursor prototype to our robot was also designed by our seniors Tanmay Mothe and Kranthi Chaitanya. However, after several meetings to Safai Karmacharis (manual scavengers), we realised that we need to upgrade the design, to make it more compliant so that no special skills are required to operate the machine.” informs Divanshu, in a conversation with Efforts For Good.

The machine, which is scheduled to be deployed on site within another three to six months, is specifically designed for septic tanks. “Many people have invented technology to clean sewer lines, but septic tanks pose a higher risk for manual scavengers. We decided to bring this problem to the limelight, which makes our robot distinctive from the manual scavenging robots already in the market,” clarifies Divanshu.

Interaction with the Safai Karmacharis made the team understand how the sludge of a septic tank differs from that of a sewer line. “In septic tanks, the sludge is highly viscous, which makes it difficult for a machine to navigate through. So we needed a robust design. Also, since the hole of a septic tank is very small, our robot needed to be compact. So we made a robot which easily slides into the tank and expands inside,” he shares.

How the SEPoy robot operates

The SEPoy robot comprises bio-inspired propulsion, whose motion is set to mimic the fin movements of a fish inside water. “The machine will go inside the tank and expand. Then it will homogenise the entire sludge and pump it out with a vacuum pump,” Divanshu explains.

High definition cameras with electronic gimbal are attached to the machine body, which turns the robot into a Remotely Operated Vehicle (ROV), that can be monitored and operated from a considerable distance. Inside a septic tank, the robot can move around in three directions and proceed forward by removing the sludge at one place.

As of now, the robot has been tested successfully in a mock setup simulated to resemble the environment inside a septic tank. The team is in close touch with NGO Safai Karmachari Andolan (SKA), which is devoted to eliminating manual scavenging from the country. The NGO has highly appreciated the invention of SEPoy and hopes it aids in their ultimate goal.

Other developmental projects by Divanshu Kumar

Interestingly, this is not the first time Divanshu Kumar has resorted to technology to address a social issue. He has started the organisation Involve Learning to develop leadership proficiency in school students through a peer-to-peer learning system, where senior students are teaching their junior classes.

The foundation is operated by Divanshu and two other youth leaders from IIT Madras. They are targeting an outreach up to 1,25,000 students in the next five years.