CHENNAI: The Union government’s move to tap treated water from sewage treatment plants (STPs) to fulfil the needs of coal power plants will not be adequate as STPs do not have enough capacity to fulfil the needs of power plants, said a report from environmental NGO Greenpeace.
According to the study, ‘Pipe Dreams: Treated Sewage will not solve coal power’s water problems’, a 1,000-MW coal-based power plant requires 84 million litres a day while most of the sewage treatment plants in smaller cities have a daily capacity of less than 20 million litres.
The Power Ministry has mapped the operational sewage treatment plants in cities that are at a maximum distance of 50 km from the power plant, and has identified 29 power plants across the country, which could be supplied with treated water from STPs. Of these, two are in Tamil Nadu — National Thermal Power Corporation Tamil Nadu Energy Company Limited (NTECL) in Vallur and Ind Bharat Power Gen in Thoothukudi.
However, according to Greenpeace, less than 8 per cent of India’s coal power plants can completely switch from fresh water to treated sewage water, while about 5 percent can partially meet their water requirements from treated sewage.
The study said switching from fresh water to treated water will not reduce the impact of coal power plants on water scarcity in the country. The cost-effective solution would be to phase out older, less efficient power plants, which tend to consume the most water. It also called for timely adoption of water consumption target set by the Environment Ministry in its notification dated December 7, 2015.
All permits for new coal plants must be halted as they are in any event not required at least till 2027 as per the Central Electricity Authority’s draft National Electricity Plan, said the report.
The report said utilising sewage as a source of water decreased the water availability in the region and has an impact similar to the use of fresh water. “Switching to treated sewage water is not a solution to the water scarcity created by coal power plants and should be done after an impact assessment,” the report said.
The way out, the report, said was moving to renewable technologies such as solar energy, which have many advantages.