Well, that almost sounds like a page out of a fantasy novel, given the water scenario many of its localities have been facing in recent years. It’s been barely two years that the city was making global headlines for having dried up completely in the wake of a monsoon failure and depleting groundwater reserves.
Was it this crisis that served as a wake up call for the Tamil Nadu government, pushing it to take steps to augment the city’s water supply and conserve water resources? How is summer 2021 going to be on the water front? What has changed in the past two years?
We interviewed V G Ramaswami, Superintendent Engineer, Central, Chennai Metro Water Supply and Sewerage Board (CMWSSB) to know the water supply board’s plan for the city.
Summer is here. What efforts have been taken in the past two years to ensure there is no repeat of the 2019 water crisis? What additional storage reservoirs were created for the city’s water supply?
To augment the city’s water supply, Sikkarayapuram quarries are to be integrated as a permanent source of water.
Last year, the board inaugurated two Tertiary Treatment Reverse Osmosis (TTRO) plants at Kodungaiyur and Koyambedu. Through these plants, sewage water is treated in multiple stages to produce 90 MLD (Million Litres per day) of water. The treated water is supplied to industries in SIPCOT and Irugattukotai.
In a first in India, Metro Water Department is setting up two plants at Nesapakkam and Perungudi to treat the sewage water. These plants, with 10 MLD capacity each, will be the ideal solution for ground water recharge in Chennai. Sewage water will be stripped of its smell and toxic pollutants through tertiary treatment with ultra filtration. The treated water will then be let into the shallow wells dug close to water bodies for the recharge of ground water. Through this method, groundwater levels within a radius of 2-3 km from the lakes (based on the soil type of the area) will be recharged. And every neighbourhood in Chennai is blessed with lakes.
The long term goal is to replace the existing method of treatment with the new technology, so that 550 MLD of sewage generated in the city can be treated and used to recharge our water bodies.
The Board has proposed tertiary treatment with ultra filtration plants of 260MLD across the city. We are awaiting funds to commence the work.
How is tertiary treatment with ultra filtration different from the existing method of treating sewage in Chennai?
Under the existing practice, raw sewage goes through secondary treatment. The pollutants are significantly removed but the smell and colour of the water remain the same. Tertiary treatment is a more effective way and is an excellent solution. The cost of these plants is much higher than that of secondary treatment plants. But it is a one-time investment that yields effective results.
We expect to set up these plants in five years. Once we are able to treat 550MLD of waste water, Chennai will be a water-abundant city even if the monsoon fails for a year or two.
How is the quality of water obtained after tertiary treatment with ultra filtration?
The TDS of the treated water obtained through this technology is 650; this water will be used to recharge groundwater.
But 5 years is a long time, what measures is the Board taking in view of summer 2021?
The two tertiary treatment plants at Nesapakkam and Perungudi will be completed in less than three months. Apart from the Sikkarayapuram quarries (30 MLD) that I have already mentioned, we will also be sourcing water from the Krishna River in Andhra Pradesh, when the water levels in the city go down. Currently, all our water reservoirs except Veeranam Lake are at 80% capacity.
Let us also not forget that we are providing 90 MLD of water through TTRO plants and thus preventing further exploitation of fresh water sources.
Desalination plants which are under construction are also expected to add to the city’s growing water needs. When will the project be completed?
A 150-MLD desalination plant is being added to the existing 100 MLD plant at Nemmeli; it will be completed in two years. The state government aims to construct a desalination plant at Perur with a capacity of 400 MLD. It is a project funded by the Japan government, currently at the tendering stage. It is difficult to give an accurate deadline at this stage, considering the slowdown due to the pandemic.
To what extent has the pandemic affected the implementation of such projects?
We have stalled many projects due to the restriction of movement during the night. As many migrant workers moved back to their hometowns, labour has become a critical problem. Yet, that has not stopped us from carrying out important responsibilities such as supplying water to the containment zones.
With just 2500 employees consisting of engineers, technical staff and others, we are working overtime to treat 551 MLD of sewerage water and procure 830 MLD drinking water. Any failure or pause in these two round-the-clock activities will disrupt water supply distribution and safe disposal of sewage in Chennai.
Will water metering for residential localities be rolled out any time soon? Can the city benefit from water meters?
Digital water meters installed in the commercial spaces of Chennai have been a hit because they save wastage of water and eventually results in water conservation. The next move is to introduce these meters in the partly commercial spaces.
In the residential segment, water meters should be uniformly installed across the city. The board will get to it once work on the 400 MLD desalination Perur plant is completed. There has been no resistance from citizens on the idea of water meters. So, it won’t take long for Chennai to follow the model of Hyderabad and Delhi in metering water consumption.
What can Metro Water do about illegal groundwater tapping for water by private tankers. How does this affect the groundwater in the city?
As most of these cases are not from Chennai, CMWSSB has no authority to take action. Groundwater from the agricultural wells of Thiruvallur and Kancheepuram are extracted illegally. The Public Works Department is currently working on a regulation, under which a database is being created. This will help to check the groundwater levels and prohibit anyone from exploiting it when the levels are already low. The regulation should be an effective solution to the problem.
However, if we are able to recharge water bodies, as proposed, with tertiary treatment of sewage water, that will ensure a constant level of the water table in and around water bodies. Then, it will not be necessary to depend on private water tankers at all.
Currently, CMWSSB has installed automatic ground water level monitors in all the 200 depot offices, which will indicate any excess extraction of ground water if it happens; necessary action will be initiated if there is a violation.
Does the Metro Water department have data on how much loss occurs in the distribution system?
According to studies conducted earlier, Non Revenue Water (NRW) was estimated at 35 to 40 percent. In the past few years, most of the pipelines and service connections were changed. There is no significant loss due to leaks in the distribution system.The current physical loss is estimated at 15%.
Many townships are extracting groundwater without getting NOC from Metro Water. What’s the procedure to get an NOC? Did the Board come up with a policy for it?
Consumers should obtain permission from the board to set up pumps above 0.5HP motor, both in open wells and borewells. There is an ongoing project initiated by the Board that aims to conduct a survey on these irregularities across the city. Those who violate the norms will have to pay annual licence fees for use of these pumps.
Dewatering — where the water table is lowered to pave way for a construction site — is rampant in the city. Experts say that this results in the diversion of aquifer flow and the depletion of water tables in open wells. Has the Board formulated any policies or restrictions on dewatering?
Again, the automatic ground water level monitors in the 200 depot offices will be able to keep such practices in check and prevent excessive extraction of ground water.
Storm water drains in the city are filled with sewage. It’s an inter-departmental issue that also involves Chennai Corporation. How does the board plan to solve it?
Citizens who are unable to get a sewage connection often let the sewage out into storm water drains. Thereby, we have simplified the procedure of getting a sewage connection through the “Illam Thorum Inaippu” scheme. Economically weaker sections can pay the sewer connection charges in ten instalments (It is a one-time investment of Rs 7500 for a 200 square metre home.)
Recently, we provided 9000 connections for 570 streets within a span of 20 days. We could provide the connections before the Corporation commenced road-laying projects in those streets. That way, we don’t have to dig up the new roads again for sewer connections.
Why is piped water supply still a far-fetched dream in localities such as OMR?
Those localities were brought under the Greater Chennai Corporation limits in 2011. After the completion of the 400 MLD desalination plant, water supply will be provided to this area, and it will be a permanent solution.
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