Though the Law prohibits manual scavenging, the practice continues unabated. For the most part, those working as manual scavengers remain undocumented, underpaid and exploited. This is a stigmatized occupation that operates from the underbelly of social negligence. Workers often receive no precautionary or safety equipment, resulting in serious health hazards and risk to life that far outweighs the meagre wages they get.


A large number of households in India (38.2 percent, as per Census 2011) use toilets connected to Septic Tanks. Septic tanks, which stored human feces from various households, are one of the most challenging environment for cleaning once it gets filled by sludge consisting of Human feces, urine, wastewater, etc. Though the Law prohibits manual scavenging, the practice continues unabated because of widespread casteism and lack of a cheaper alternative. Because of the poisonous environment that it has, it’s been reported as one of the most dangerous occupation killing at least 500 workers every year.

Team SEPoy at IIT Madras has been trying to develop an automatic robot, SEPoy, which would homogenize the sludge and clean it. SEPoy is an inverted umbrella mechanism based robot whose key features include opening arm mechanism, modularity, compactness, minimalism & spark proofing of all parts inside the septic tank. It also encompasses various concept validations which finally led to the development of a full-scale prototype.

Our work includes understanding how the robot goes inside the septic tank and how the cutting mechanism will work out. We are developing a mechanism by which the cutter can enter through small openings and subsequently perform homogenization of the tank contents. Once the hardened sludge is broken down, it can eventually be sucked off using vacuum pumps

We are also trying to develop a pathway towards sludge research and creating synthetic sludge which mimics the viscosity and shear rate of actual sludge. This can go a long way into developing lab-based conditions that can propel more research into testing the prototypes without actually having to enter septic tanks. Here is the Link to a couple of Press coverage that we have received:

The Hindu: Coming soon — a robot to clean septic tanks
The Better India: Coming Soon: The ‘SEPoy’ of IIT Madras That Could End Manual Scavenging




Posted on

April 23, 2019

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