A team of CDD engineers takes a sample of treated wastewater at a factory in Bangalore. (Photo by Julia Knop, courtesy of CDD) 

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News headlines such as “Half of homes have phones but no toilets,” and the diligent efforts of the government of India and nonprofits to provide toilets to the 48 percent of Indians who don’t have one, suggest that enough toilets will solve India’s sanitation woes. In reality, while toilets are a necessary part of the solution, an arguably bigger yet often overlooked issue is how to contain and treat India’s sewage. Currently, 93 percent of sewage finds its way to ponds, lakes, and rivers without treatment.1

Untreated sewage is the leading polluter of water sources in India, causing a host of diseases including diarrhea (which kills 350,000 Indian children annually2), agricultural contamination, and environmental degradation. The urban poor often live alongside dirty drains and canals in which mosquitoes and germs breed.

India’s largest cities have centralized sewage systems, complete with underground pipes, pumping stations, and treatment plants. However, these systems are expensive to build and to operate, requiring uninterrupted power, skilled operators, and extensive maintenance. As a result, according to India’s Central Pollution Control Board, fewer than half of them work effectively.3 What’s more, India’s smaller towns cannot afford to build such systems. The good news is that a handful of organizations are developing sewage systems that are less expensive and more effective. Prominent among them is the Consortium for Decentralized Wastewater Treatment System Dissemination Society (CDD), a nonprofit organization that has been developing and promoting technologies for decentralized wastewater management since 2002.

CDD’s Decentralized Wastewater Treatment System (DEWATS), developed with support from the Bremen Overseas Research and Development Association, has adapted multiple technologies to conditions where electricity is not reliably available, skilled manpower is hard to come by, and mechanical parts that break may never be repaired.

The system is designed to encourage the development of smaller, more affordable systems to treat wastewater closer to the point of generation, enabling more effective water reuse for toilet flushing and gardening. Using natural bacteria, plants, and gravity instead of electricity and chemicals, DEWATS can be up to 80 percent less expensive to operate than conventional technologies. DEWATS can also help tackle water shortages, because it can reduce the use of freshwater by up to 50 percent for domestic uses locally, like washing, flushing, and gardening.

CDD has more than 150 clients in 13 Indian states. It also has 25 clients in Nepal and Afghanistan. And the organization is poised to do much more. For example, to meet the varied needs and constraints of clients, CDD’s partner, Auroville Centre for Scientific Research, has developed a “vortex” system that reduces land requirement by 90 percent. CDD is also developing modules that can be mixed and matched to suit the needs of communities and their budgets. “Most of the DEWATS can be built underground, and the land above can be used as a garden or parking space,” says Sasanka Velidandla, CEO of CDD.

Consider: In November 2015, CDD commissioned a fecal sludge treatment plant in Devanahalli, a town of 31,000 near Bangalore. Built using a simple and low-operating cost approach, the plant has so far prevented about half a million liters of fecal sludge from polluting the environment. What’s more, CDD distributes the treated sludge to local farmers, who use it as an organic soil conditioner. With CDD’s support, the local town council has passed resolutions to introduce comprehensive fecal sludge management processes.

The CDD team is encouraged by the results it is seeing, but with nearly 37 billion liters of untreated sewage generated by India’s cities every day,4 the organization has its sights on the future. “Sewage management is finally a priority,” says Velidandla. “Large-scale investments are being planned, and we want to ensure that all options are properly evaluated so that sustainable infrastructure is developed.”

But CDD, even with its current partners, can’t realize its vision alone. “We keep asking ourselves, how do we multiply our impact?” says Velidandla. “We innovate, and pilot, and test continuously because it’s important to get it right—but the time to act is now. We plan to be working in five states to design and implement comprehensive solutions, and to do that we need all the partners and support we can find.”