Despite prohibitory orders and bans on manual scavenging in sewers and septic tanks, there have been many deaths due to this practice. As per the statement of the Ministry of Social Justice and Empowerment, in the last five years till December 31, 2020, 340 deaths occurred in 19 states and union territories due to manual scavenging in sewers and septic tanks.
In November 2021, a group of students from the Mechanical Engineering Department and Centre for Non-Destructive Testing (CNDE) of IIT Madras have developed a robot, named, Homo SEP (Homogeniser of septic tanks) which can clean septic tanks mechanically. It is a joint venture with Solinas Integrity Private Limited, a start-up owned by an alumnus of the Mechanical Engineering group of IIT Madras. The developers claim that once deployed extensively, the robot will put an end to the practice of people entering the septic tanks and sewers to clean them. The robot took around three years for its completion, starting in 2019.
How HomoSEP Works
HomoSEP can open like an inverted umbrella when introduced into a septic tank, as it has a shaft attached to blades. It has been modelled in such a flexible way that it can adjust to the narrow opening and bigger interiors of a septic tank. HomoSEP shreds and homogenises the faecal sludge inside the septic tank which is thickened like hard clay and settled in the bottom. Once this process is done, the homogenised sludge is sucked out and the septic tank is cleaned. The rapidly rotating blades of the robot do this precisely.
The engineers had initially designed a fish-like model which could provide an inside look into the contents of the septic tanks and sewers. However, after the feedback from the workers, the engineers realised that they required a simpler device to homogenise (to blend diverse elements into a mixture that is of the same consistency throughout) the contents of the septic tank. The model was bulky, heavy, and a stationary unit. It also needed external power from the mains or from a battery.
The latest model, however, has a sharpened and improved blade design, and miniatured, so that two people can carry the robot. It is lightweight and can be attached to a tractor. It can be wheeled off to remote and inaccessible areas. The robot is attached to the axis of a tractor and can be run using the power from the tractor’s engine. Once the work is completed, the robot can be detached from the tractor.
Tests and Availability
The trials and tests were conducted with the sludge-like material with similar properties. The feedback and validation of HomoSEP’s performance was taken from the members of Safai Karamchari Andolan. It was also tried and tested in a set of septic tanks.
Initially, eight units would be distributed in Tamil Nadu and soon would be distributed to Gujarat and Maharashtra. If this works out then there would be a respite for manual scavengers. Many deaths could be avoided due to manual scavenging of septic tanks and sewers.
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