Residents in several parts of Chennai have complained of water supply being contaminated with sewage. However, authorities only offer a temporary fix, they say.

Sewage leaks into water Chennai residents cry foul Metrowater blames it on science
news Water Tuesday, April 23, 2019 - 08:02

For residents in water-starved Chennai, the dwindling supply is not the only concern this summer. It’s the quality of water that is coming from their taps that is more worrying.

Take the case of 68-year-old Uma Shankar, a resident of Mandaveli in Chennai, who was aghast when she opened her kitchen tap last week. What gushed out was not clear water, but a thick black liquid that reeked of sewage. She immediately rang up her daughter Ganga Sridhar who lives a few buildings away on the same street to apprise her of the situation.

“I called the Assistant Engineer (AE) of Chennai Metropolitan Water Supply and Sewerage Board (CMWSSB) to ask him why the water supplied was mixed with sewage. He told me that a sewer line in Adyar had a major leak and acknowledged that it had permeated into the water lines. It was beyond me how both can even mix and how he can be all normal about this,” says Ganga

But this is not a one-off incident. Chennai residents have been at the receiving end of sewage-mixed water for years now and the frequency has spiked over the last six to seven months.

The carrier of infections

Consumption of such contaminated water is a cause for serious health issues-with cases of diarrhea and vomiting being reported from the city.  Aakash Jacob, 33, who also lives in Mandaveli’s Raja Street says his apartment received contaminated Metrowater on April 18. He says he realized that the supply had sewage mixed with water because of the stench.

“We figured out the smell was coming from the taps, which was supposed to supply drinking water. We decided to drain all the water and get a fresh supply. We let our taps flow for three hours. By the time we realised the water was contaminated we had brushed our teeth and taken a bath,” he says.

As a result, Aakash’s 60-year-old mother first fell ill followed soon by his father and his two-year-old toddler. “The building manager said this problem has been happening from 2016 and that complaints to CMWSSB have not been resolved. We have now completely shut off the valve that brings in Metrowater. But the residue is still in the tank and that scares us,” he points out.

Shashank Ramesh’s family who live in Shenoy Nagar have also had to suffer from vomiting and diarrhea due to the contaminated water.

Recurring problem

Ganga Sridhar points out that though the CMWSSB workers have been attending to the problem of contamination, the fixes have been temporary.

“The issue began in December 2018. Whenever we lodge a complaint with the CMWSSB, they will send someone to check it and correct it. But the problem reappears shortly after,” she says.

A sample of the sewage-mixed water from Adyar. 

Shashank also points out a similar pattern in his locality. “When the problem began in March, we were getting foul smelling water for about a week. We drained the water out and let the good water come. And then it became fine. Very shortly after that episode, contamination happened again after which we cleaned the pipes and it got better for a week. Now again this week, we are getting dirty water in Metrowater pipes. Every time we clean the tank and the pipe, the water is again mixed with sewage,” he rues.

Raja*, a resident of Narayanan Street in Mahalingapuram says that he has been receiving sewage-mixed water for three years now. “Earlier, the mixing used to happen once in three months. We live in a dead-end street and except for the first few houses the rest of us have stopped using corporation water. There are 12 houses on the street. On complaining, CMWSSB does temporary fixes but the contamination happens again immediately the next time we fill the tank,” he explains.

‘CMWSSB officers told us to keep inlet valves shut’

What perhaps irks the residents across the city is the same answer they have gotten from CMWSSB officials and other plumbers.

Ganga says that the Assistant Engineer of her area urged them to shut the water inlet valve to the sump on days when there is no water supply as a solution to address the problem. However, Ganga says that it is an irresponsible answer. “The AE telling us to keep the inlet valves shut on non-supply days is like saying that CMWSSB will be sending sewage on and off, but you please don’t receive it,” she explains.

Shashank also says that the plumber who serviced the pipe at his house also said the same thing – to keep the water inlet pipe closed during non-supply days.

CMWSSB grossly negligent: Arappor Iyakkam

Arappor Iyakkam, a Chennai-based citizens’ rights group, alleges that water contamination is solely due to the incompetence of CMWSSB in handling sewage water and drinking water supply.

Speaking to TNM, Jayaram Venkatesan, the Convener of Arappor Iyakkam says, “This could have happened because sewage is not being released properly. This is visible everywhere in water bodies. CMWSSB says they spend 95% time on drinking water and 5% of time on sewage management. This means they are not looking at the issue holistically.”

He further adds that the present system of collecting and treating sewage by the CMWSSB is not proper and attributes the lack of implementation to negligence by the water authority.

A problem without a permanent fix

Though residents continue to complain about the stench and the health hazards, it seems that CMWSSB can only do so much about it.

A senior officer at the water authority, who spoke on condition of anonymity said that this mixing is due to a rather scientific process that happens within the pipeline.

“When people operate pumps to see if they can get water when there is no actual supply in the lines, an area of negative pressure is created inside the pipe. This pressure weakens the joints made of rubber, lead or spun yarn. The negative pressure sucks the sewage water at points where sewer lines crisscross or are adjacent to water lines and the sewage water is stagnant. The sewage thus mixes with the water during supply days,” he says adding that ideally during non-supply hours pumps must be kept totally idle.

The officer further says that this problem does not happen when water supply is abundant since there are no vacuum areas inside the pipes. “Since the pipelines are below the surface, it is very hard to identify the source of this mixing. We will come to know only when residents complain and bring the matter to our notice,” he adds.

Speaking about ways to address the problem, the officer says that decentralization of the Metrowater pipeline network will only help in the long run. “It is easier to identify and fix the problem too that way. Contamination, if any, can also be restricted to a smaller area. So over a phased manner, the network of pipelines must be made simpler and smaller,” he adds.

Apart from that, he recommends apartment complexes to think about using recycled water for tertiary purposes like gardening. “Around 10% of supply is only used for cooking and other primary purposes. But we end up supplying 100% good water for all our needs. Only then we can address this on a long-term basis. Infrastructure fixes can only do so much,” he points out. 

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