Currently, 93 per cent of sewage finds its way to ponds, lakes, and rivers without treatment. Untreated sewage is the leading polluter of water sources in India, causing a host of diseases, agricultural contamination, and environmental degradation. The untreated sewage is dumped directly into water bodies, polluting three-fourth of India’s surface water resources. An estimated 75 to 80 per cent of water pollution is from domestic sewage, discharged untreated into local water bodies.
Recent developments in Devanahalli, a town 40 km from Bengaluru, offers us hope that our urban centers can effectively address issues concerning sewage treatment. In November 2015, in partnership with local Town Municipal Corporation (TMC) and the Bill and Melinda Gates Foundation, Consortium for DEWATS Dissemination (CDD) Society commissioned India’s first city-wide and dedicated faecal sludge treatment plant (FSTP) at Devanahalli. This FSTP has helped the town of just 30,000 people to move towards an open defection free environment.
Now, Devanahalli is an ODF+ town with all residents having access to a toilet, besides possessing the facility to regularly and safely collect, transport and treat all faecal matter. A large part of this effort is thanks to the tech giant Oracle India.
“Before setting up the FSTP at Devanahalli, we set up a pilot at our office campus. Faecal sludge characteristics vary greatly based on weather, containment system, desludging, frequency etc. So, at this pilot plant, we tested the technology before setting it up townscale at Devanahalli,” said a spokesperson for CDD Society, speaking to The Better India.
The technology was designed based on inputs from engineers at CDD and its partner, the Bremen Overseas Research and Development Agency (BORDA).
How does this FSTP work?
“Faecal sludge is collected in desludging vehicles (aka honeysuckers). These desludging vehicles bring the faecal sludge to the treatment plant. The solid stream goes into anaerobic digestion and biogas is produced. It is then further treated and stabilised in anaerobic reactors.
Finally, it is dried in a drying bed and ready for co-composting, where it is mixed with organic municipal waste and co-composted into useful soil manure or compost for farmers. This cycle balances the nutrient requirements of the soil that’s depleted through agriculture and overuse,” says Sasanka Velidandla, CEO of CDD Society.
The entire plant runs on gravity. It doesn’t use any electricity for its operations. Not only has it proven to be effective and cheap, but it also does not leave behind a significant carbon footprint. Moreover, it’s close to the source of faecal sludge.