Can a book called Excreta Matters make for riveting reading? You wouldn’t think so, but it does. Published by the Centre for Science and Environment (CSE) and available in online book stores, the book is an exhaustively researched work on how sewage—hold your breath—comes right back into our homes as water supply after getting dumped in rivers and lakes. Alarming, isn’t it? But a two-day seminar on this subject conducted by the CSE earlier this month had academicians, activists and civil servants say the same thing and share stories of how they are managing the humongous challenge of dealing with India’s water and waste.
The current system is that concrete underground sewers carry excreta to a sewage treatment plant (STP) through a large quantity of clean water (the toilet flush). At the STP, it gets treated and recharged into our water bodies. There are two problems that this throws up:
Firstly, as the population of cities keeps exploding (340 million Indians currently live in cities), the system is under huge strain. Building and maintaining the concrete pipes of underground sewage systems is capital intensive. Our municipalities don’t have that much money. (Really? What happens to our taxes?) so, large parts of our cities do not even have underground sewage and some of the STPs do not function as the recurring costs of electricity and chemicals is too high. And we are still talking only of sewage of the urban “developed” areas. But rich or poor, when you gotta go, you gotta go, so there is also sewage generated by slums and unauthorized colonies whose destination no one knows of.
Here are the statistics CSE has worked out after studying 71 Indian cities: The class I and II cities of India generate an estimated 38,355 million litres of sewage per day (MLD). The installed capacity to treat is 30%, so 11,788 MLD. Assuming that installed STPs work at 70% capacity, the sewage actually treated is 8251 MLD. So, 225 of the sewage generated is treated and 78% goes untreated.
What is the meaning of “goes untreated”? Where does it go?
Into our waterways, say the experts, which brings us to the second problem of polluted rivers. Each city discharges its waste into a river and forgets about it. But an axiom of life that was repeatedly stressed in the conclave is that “we all live downstream”. In other words, for cities below you, you are the pigeon but for those above you, you are the statue. As settlements increase, so does the muck discharged by STPs into the rivers and lakes. “Rivers are not rivers, but modern sewers. People downstream drink the sewage of those upstream,” says the CSE report.
“How can it be that bad? Doesn’t the river water get treated before it is supplied to us?” I asked Deepak Kantawalla, a septuagenarian environmental engineer who was honoured in 2012 with an alumni achievement award by his alma mater, the Washington University at St.Louis. “People like us who live in the richer areas of big metros get treated water. But the treatment is not thorough in several towns of India, especially for towns near water bodies,” he said.
This is not a new problem. Kantawalla told the audience that he’s been saying the same thing for forty years. But as cities expand the problem becomes more pressing.
Gaurav Gupta, chairman of the Bangalore Water Supply and Sewerage Board, explained how Bangalore’s population was 1.5 million 40 years ago and is now 9 million compounding the civic challenges. “How to intercept the sewage line of each house and take it to an STP is a big problem as more homes come up. So is supplying water to them. Bangalore has to pump up water from the Cauvery 1,000 ft below.” It has to do that because Bangalore’s many lakes which supplied water have been filled up for construction to accommodate the population. Others have dried up or become too polluted.
How should we cope with this situation?
Decentralising sewage treatment and finding smart ways to reuse the waste we generate. In Bangalore the Sewerage Board sells treated sewage to airport, institutions and the railways to use for landscaping and water requirements, including to Cubbon Park and Lal Bagh.
Kantawalla recalled that there were buildings in Mumbai even in the 1960s with an STP plant in the basement and the treated water would be used for the air-conditioning plant.He pointed out that the Gandhian Ishwarbhai Patel, India’s “toilet man”, had designed many innovative single flush toilets and dry toilets. Waterless urinals are an alternative.
Then, there are systems of composting human waste and turning it into biogas or fertilizer which can be adopted in both residential and industrial buildings.
The CSE in its Okhla office transports used water of toilets to a sump where a bassle reactor, which is like an extended septic tank, breaks the sewage and organic waste in the water. Then it goes to a reed bed, a rectangular patch of land filled with pebbles, in which flowering plants grow. These remove the remaining pollutants in the water which is then pumped up into a tank and used for watering plants in the office.
Consultants who design a “constructed wetland for sewage treatment” can do this for anyone with a 2x10m patch of land, even in a parking lot. This is called Phytorid technology and the National Environment Engineering Research Institute (NEERI) has used this in many sites. The estimated cost is about Rs.1.25 lakh for the whole project. Malini Shankar, Principal Secretary of the Maharashtra government who heads the water resources department, said that decentralized sewage systems using this technology had been set up in 70 villages in Maharashtra, which have a population of less than 15,000 people and were maintained through community participation.
There is obviously no dearth of ideas, as these initiatives show. As Kantawalla said, “There is only a dearth of will and applying our head.”
Vandana Vasudevan is a Delhi-based writer on urban consumer and civic experiences. Your comments are welcome at email@example.com.