Mechanised cleaning of Septic Tanks: a socio-technological review
Mechanised cleaning of Septic Tanks: a socio-technological review
Authors: Linda Jasline, Bhavesh Narayani, Divanshu Kumar & Prof. Prabhu Rajagopal,
Solinas Integrity Private Limited and Center for Nondestructive Evaluation, IIT Madras
- Societal context and Background
Dignity is an inalienable right which is part of the fundamental right to life. Justice systems all over the world have held human dignity to be the most important, fundamental, inalienable and transcendental of rights. Yet, even after more than 70 years of independent India we find a section of the society, the scavenging community, being deprived of this and being predominantly engaged in the practice of manual scavenging. The Supreme Court found in 2014 that there were over 9.6 million dry latrinesin India which required manual emptying. In other data points, there are over 75 million households, which are connected to septic tanks that may require manual scavenging, comprising 40% of the households. Traditionally, entire cleaning of the septic tank is done by manual scavengers, as shown below in Fig.1
Indian law, the Prohibition of Employment as Manual Scavengers and their Rehabilitation Act 2013, which is the current law against manual scavenging, prohibits dry latrines and all kinds of manual cleaning of excrement as well as cleaning gutters, sewers, and septic tanks. This was an improvement from the earlier 1993 law which only gave importance to dry pit latrines. The act of 2013, apart from recognizing this dehumanizing practice arising from the inequitable caste system, also recognizes how manual scavengers are prone to serious injury and are always at a risk of death. The act envisages that sewers should be cleaned mechanically while manual scavenging will only be permitted in exceptional cases, with safety equipment by the employer. If unfollowed, this is considered a criminal offence even when it does not result in injury or death. The offender can be charged with a maximum of five years imprisonment and a fine of five lakh rupees. Additionally, an association of safai karamcharis, called Safai Karamchari Andolan, led by Bezwada Wilson (Ramon Magsaysay Awardee) has been instrumental in bringing the attention of common public to the issue and rehabilitating some of them.
Despite these efforts the practice continues unabated. Deaths arising from manual scavenging are commonplace in India, (1000+ people die every year cleaning these tanks) and there has been press attention turned to the scavengers’ dangerous conditions of work in the National Capital. A 2019 study done by the WHO (World Health Organization) showed that “weak legal protection and lack of enforcement” of the laws as well as the sanitation workers’ poor financial status (as the rehabilitation schemes remain ineffective) were the major contributors to the practice still existing. India is a federal democracy and sanitation remains under the purview of the states. Hence the implementation of the laws of manual scavenging remains under them, without any compulsion and commitment. Though some municipal bodies have begun adopting machinated sewer and septic tank cleaning in this attempt, this is occurring at a very slow pace. Lastly, this is a complex problem at the intersection of a complex caste system (shaping public perception) and lack of technological development towards solving this issue.
- Technological Solutions from India/elsewhere addressing Manual Scavenging
| Fig. 2: Photograph of giant ball for sewerage lines http://theballreport.com/the-sewers-of-paris-are-cleaned-by-giant-balls/ |
Fig.3: Photograph of a sewer cleaning machine
https://www.mylaporetimes.com/2010/12/new-sewage-cleaning-machine-for-zone-x-a/ |
| Fig.4: Photograph of a sewer jetting machine | Fig.5: Photograph of a Mini sewer jetting machine |
Minimal effort was given to finding a solution for this demeaning problem for several decades and no lessons were learnt from other countries in this aspect. In France giant balls, but smaller than sewerage lines, are pushed using water at high pressure to unclog the sewers. Until now, there have been a few solutions that have been found in India. Some of the technologies that are available in the Indian market for sewer system cleaning are sewer drain jetting trucks, sewer jetting and flushing machines, gas detector masks, and sewer cleaning robots.
Apart from equipping the workers with technology, several rules must be followed to ensure safety. Safety training is critical and all employees associated with the job must undergo it. Written instructions and procedures need to be provided to the workers and continuous supervision during the job must be done. To operate the equipment, the workers present at the site need to be familiarized with how to operate. In addition to that, workshops are to be conducted at least once every two years to update them on the improved methods and techniques. Manual scavengers need training to use the dedicated technologies available in the Indian market thus enabling them to live a life of dignity.
- The approach that may work
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 wellbeing.
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
- Solinas, an IIT Madras incubated startup developing HomoSEP Robot to aid Sanitation workers for Cleaning Septic Tanks
A team led by Mr. Divanshu Kumar at the start-up Solinas Integrity Private Limited in collaboration with Dr. Prabhu Rajagopal at the Center of Non-Destructive Evaluation (CNDE), IIT Madras has been developing the ‘HomoSEP’ robot for automated homogenization & cleaning of Septic Tank contents. In the last year, the team has successfully 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. A start-up “Solinas Integrity Private Limited” led by Mr. Divanshu Kumar and Dr. Prabhu Rajagopal in collaboration with Center of Non-Destructive Evaluation (CNDE), IIT Madras has been developing the ‘HomoSEP’ robot for automated homogenization & cleaning of Septic Tank conHomoSEP robot developed by Solinas Integrity Private Limited in collaboration with Center of Non-Destructive Evaluation (CNDE), IIT Madras
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.
Solinas solution, the HomoSEP robot will be available from December 2021 for cleaning septic tanks. This robot will be operated by a worker using a portable remote control panel and screen.
HomoSEP robot developed by Solinas Integrity Private Limited in collaboration with Center of Non-Destructive Evaluation (CNDE), IIT Madras
About Authors :
1. Mr. Divanshu Kumar, Heading Involve Education & Solinas Integrity, IIT Madras | PM Awardee,
https://www.linkedin.com/in/divinvolve/?originalSubdomain=in
2. Mr. Bhavesh Narayani, Head of Product Development at Solinas Integrity, IIT Madras
https://www.linkedin.com/in/bhavesh-narayani-32a1a8144/?originalSubdomain=in
3. Ms.Linda Jasline, Project Manager at Solinas Integrity Pvt. Ltd, IIT Madras https://www.linkedin.com/in/lindajasline/
4. Prof.Prabhu Rajagopal, Faculty in charge, Centre for Innovation at Indian Institute of Technology, Madras
https://www.linkedin.com/in/prabhu-rajagopal-041ab74/?originalSubdomain=in
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If interested:
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