Solinas approach to eliminate manual scavenging

Taking a socio-technological approach to solve this problem could provide us a potential solution. Firstly we need to understand the problem of cleaning fundamentally and then look at technological solutions. Moreover we need to work on ground with people and empower them to leverage these technologies for themselves, thereby contributing to their financial well being. 

Cleaning hard sludge from the bottoms of septic tanks and sewer lines is vital in the sanitation industry. Septic Tank is a poisonous environment, filled with a semi-solid and semi-fluid human fecal material that makes up about two-thirds of the tank. Diving further, the fecal sludge actually starts solidifying into a clay-like substance and toward the bottom it gets rock-hard. Once filled, they are required to be cleaned every 2-5 years to stop sludge overflow and groundwater contamination. However, this results in the gradual accumulation of un-pumpable sludge at the bottom of the pit, which eventually fills the latrine and forces it to be abandoned. This is where manual scavengers come into the picture. The workers who are often assigned to clean the septic tanks die due to suffocation, exposure to toxic gases, that results in skin and breathing disorders.  This is a stigmatized occupation that operates from the underbelly of social negligence. 

Developing HomoSEP Robot to aid Sanitation Workers for Cleaning Septic Tanks 

A team of alumni from IIT Madras has been developing the ‘HomoSEP’ robot for automated homogenization & cleaning of Septic Tank contents. In the last year, the team has completed trials of the next version of HomoSEP robot (v2.0) which is more rugged and miniaturized for portability under laboratory, mock-up and field conditions. 

This HomoSEP robot will aid manual scavengers in cleaning the hard sludge without entering the potentially dangerous atmosphere of a septic tank. HomoSEP is a compact robot made up of five main modules. The bottom module can homogenise hard sludge with water to create a pumpable slurry, and the feeding machine module can push and pull the bottom module inside a septic tank manhole at a depth of 3-5 metres. The portable module is mounted on a mobile frame to hold the whole robot at actual septic tank sites. The electronic module is configured so that the entire robot can be operated by the manual scavengers with a single remote. The suction module is intended to suck the homogenised slurry from the Septic tanks.

It is envisaged by Solinas that the HomoSEP robot will be available from December 2021 commercially as a solution for mechanized cleaning septic tanks. This robot will be operated by a worker using a portable remote control panel and screen.


By Bhavesh Narayani,
Head of Product Development, Solinas