Waste to Worth: Be Excreta Wise

The fact is, this treated water and sludge is rich in nutrients. Today, the global nitrogen cycle is being de-stroyed because we take nutrient-rich human excreta and dispose of it in water. Instead, we can return the human excreta to land, use it as fertiliser and reverse the sanitation cycle. The treated water can be given to industry or cities for reuse. Farmers can use the treated sludge for soil enrichment. But this also means that we need new standards to be set for reuse of treated wastewater, so that basic nutrients needed for land are not lost in the treatment

Every society must understand how the excreta it produces is managed. It teaches us many things about water, about waste, about technologies. It also teaches us about economics and politics: of who in our societies is subsidised to defecate.

Every society must connect the dots between the excreta it produces, the pollution it causes and the opportunity to reuse and recycle the waste so that it becomes a resource. This is what the Centre for Science and Environment’s (CSE) report, ‘Waste to Worth,’ is all about—it puts together the best prac-tices to turn wastewater into water and not pollution. Today, the discharge of effluent is adding to the water crisis by degrading available water through pollution. It is also adding to our health crises as socie-ties continue to drink this “sewage”-laced water. All this then points to the solution ahead—the way to take that “wasted” water and make it “usable” so that it can be returned to the hydrological cycle.

Over the years, my colleagues have studied the excreta sums of different cities. The city “shit-flow” dia-gram shows that the situation is grim as all cities either do not treat or safely dispose of the bulk of the human excreta. This is because we often confuse toilets with sanitation. But the fact is that toilets are mere receptacles to receive waste; when we flush or pour water, the waste flows into a piped drain, which could be either connected, or not, to a sewage treatment plant (STP). This STP could be working, or not. In this case, the faecal sludge—human excreta—could be conveyed, but not safely disposed of as it would be discharged into the nearest river, lake or a drain. All this will pollute. In most cities, this con-nection from the flush to the STP does not exist.

According to Census 2011, the flush water of some 30 per cent of urban India is connected to a piped sewer. But our survey found that in most cases, these underground drains have either lost their connec-tions—they need repair—or are not connected to the sewage plants.

There is another route for excreta to flow. The household flush or pour latrine could be connected to a septic tank, which, if constructed well, will retain the sludge and discharge the liquid through a soak pit. The faecal sludge would still need to be emptied and conveyed for treatment. But in most cases, our sur-vey found that the septic tank is not built to any specifications—it is a “box” to contain excreta—and that it is either connected to a drain or emptied out. This is where the drama of faecal sludge begins. Who collects it? How is it transported? And most importantly, where does it go? Nobody knows.

That is why the focus is now shifting towards intercepting the sewage—not through capital-intensive underground pipes but through tankers to transport this for treatment. Septic tanks are decentralised waste collection systems. Instead of thinking of building an underground sewerage network—that is never built or never completed— it would be best to think of these systems as the future of urban sani-tation. After all, we have gone to mobile telephony, without the landline. Individual septic tanks could be the way to achieve full sanitation solutions.

For this, the government has made changes in policy and now practice—it has recognised that these systems exist and that they need to be incorporated in sanitation plans. It is providing regulation for the collection and transportation of faecal sludge so that waste is taken for treatment, and not dumped somewhere. And most critically, city governments are working on a treatment system for faecal sludge, which in turn will reduce the pollution in rivers and lakes. But now the challenge is to reuse this treated water.

This is where the real opportunity lies. The fact is, this treated water and sludge is rich in nutrients. To-day, the global nitrogen cycle is being destroyed because we take nutrient-rich human excreta and dis-pose of it in water. Instead, we can return the human excreta to land, use it as fertiliser and reverse the sanitation cycle. The treated water can be given to industry or cities for reuse. Farmers can use the treat-ed sludge for soil enrichment. But this also means that we need new standards to be set for reuse of treated wastewater, so that basic nutrients needed for land are not lost in the treatment. This approach makes the users of this treated water the agents to ensure compliance with standards. Just imagine if you were to be a consumer of this treated water for your horticulture needs—you will be vigilant of its quality and the fact that it does not contaminate your land. So, we can be water-secure, because we are water-wise.

(Writer is Director General of CSE and editor of Down To Earth, an environmentalist who pushes for changes in policies, practices and mindsets; Courtesy: https://www.downtoearth.org.in/)