Tank Agitator Aims to Prevent Worker Deaths In India

Could elements of the HOMOsep robot migrate to North America to make pumping easier and safer?

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Agitating the contents of a neglected septic tank is certainly one challenge for service providers in North America. Many of you address that challenge with stirring poles or Crust Busters to loosen the hardened fat cap at the top of the tank or the thick sludge at the bottom. In the western world, we have solutions to make this work safer and easier for service technicians.

         It’s a different story in other parts of the world, especially in India, where hundreds of day-working septic tank cleaners die every year when they enter the tank and are overcome by hydrogen sulfide gas. In many cases, multiple workers are killed as the next person in line enters the tank in an effort to save the worker who has passed out.

         These workers are called “manual scavengers,” and they are paid as little as $4 per day to provide this dangerous service without being provided proper safety gear and gas-monitoring devices. The practice has been outlawed by the Indian government; however, these tragedies continue to occur because using manual scavengers is much less expensive than hiring a contractor with proper vacuum equipment. A recent news account out of India said two brothers were hired for just under $10 said to be twice their normal daily pay, to empty a septic tank. The first brother entered the tank using a rope and with no protective gear, while others stood by. One story explained that the only safety measure many Indian septic workers take is holding a lighted match inside the tank opening. If the match burns to the end, they assume the air quality is OK and they proceed.

         When the first brother passed out, the second brother went in after him and was also overcome by the gas. Then another man went in after them and also succumbed. After the tank was emptied by a vacuum truck, the three bodies were removed. One news account stated they were among at least nine sanitation workers who died that month.

         These stories are inconceivable to pumpers in the U.S. who are required to follow stringent safety regulations for confined space entry of septic tanks.


         Researchers in India are trying to prevent these deaths with a new product called the HOMOsep robot, which combines agitation and a built-in suction pipe. The unit is mounted to the back of a farm tractor and can be operated by the septic service workers safely from aboveground. You can see the unit in action in this YouTube video: www.youtube.com/watch?v=KXyFj36z_Ls.

         To call the HOMOsep a “robot” is frankly gilding the lily. I wouldn’t equate the technology with some type of sophisticated artificial intelligence; however, it made me wonder if a similar device could be developed here to take away some of the backbreaking work and allow pumpers to service more tanks in a day.

         The unit consists of three rows of fixed triple blades, each about a foot in diameter, and a larger triple-blade fan that retracts to fit inside the tank opening, then opens when pushed to the bottom of the tank. A suction pipe runs through the center of the blade assembly. The spinning unit loosens the sludge while waste is pulled through the pipe and into a vacuum truck.

         The HOMOsep was developed by the Indian Institute of Technology Madras, and the IIT Madras Department of Mechanical Engineering, along with startup company Solinas Integrity. It is also supported by an NGO, non-governmental organization called Karamchari Andolan which is working to end manual scavenging in India.

         Bhavesh Narayani, of Solinas Integrity, told Indian media that the project to keep septic workers out of tanks has been rewarding. So far 10 units are in use and being monitored, with hopes to ramp up production.

         “We improved the blade design through extensive simulation and mock-up trials and achieved a miniaturization for better portability. Moreover, we integrated our product with a tractor so it could reach remote locations,” he said in one news account.


         Think about how far our industry has advanced in North America compared to this story coming out of India. What’s a life-and-death issue in an emerging economy very rarely comes up over here. However, that doesn’t mean we are immune to the tragedy of workplace injury or death in the states. Even with clear-cut safety regulations controlling confined space entry, we still see occasional deaths from hydrogen sulfide gas poisoning. We also see occasional trench mishaps, slips and falls, and other construction-related injuries and death.

         And I still see some horrifying and disappointing examples of safety violations by septic service providers in the U.S. Just recently, someone posted a photo on a social media site showing a woman who entered a tank to make a repair without any safety equipment in sight. The worker was in the tank up to her neck and was smiling up at the camera. The poster was proud of their coworker for her willingness to get down and dirty to solve a problem in a customer’s tank. Several pumpers jumped in and warned the poster that this was a dangerous safety violation and it shouldn’t be treated lightly. They said there were many ways to approach an issue inside the tank without entering it, and stressed that if tank entry was necessary, it should only be done while following all Occupational Safety and Health Administration rules for confined space entry.

         While it was good to see those responses, it was equally mystifying to see just as many people dismiss the warnings and congratulate the pumper for the guts to get in the tank and get the job done, no matter the risk. Attitudes like these are dangerous and could lead to injuries or death among the valued members of our pumper community and they should not be tolerated.

                  Please note the efforts to save so many lives tragically lost in septic tanks in India. Take the time to speak out if you see unsafe practices in the field. Make sure your crew has all the necessary safety equipment and training they need to do their jobs right and make it home to their families every night. 


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