The state government has said that desalination plants will figure prominently in the strategy to augment drinking water sources in the state. Besides two new plants in Chennai for over 450 MLD, the government has planned for more in water-starved districts such as Ramanathapuram and Tuticorin.
A recent TOI article ‘Desal plant does little to quench thirst’ (Aug 5), however, showed that production at the Nemmeli plant in Chennai fell to a fraction of the capacity of 100 MLD on many days due to fluctuations in power supply and presence of sand particles in sea water.
In Ramanathapuram, where desalination plants have been operating for several decades, the experience has been quite similar. Bogged down by operational issues, many of them are not operational.
Even the flagship project of the state at Naripayur in Kadaladi taluk of Ramanathapuram district is functioning at its half capacity of 1.9 MLD against its total capacity of 3.8 MLD. A plant in Rameswaram with capacity of 1 MLD stopped functioning eight years back due to technical problems. Problems have been encountered in the remaining 22 small desalination plants that use brackish groundwater.
A Arjunan, municipal chairman of Rameswaram, said that even as the plant in his home town suffered technical problems, Cauvery water arrived. “We have fresh water sources in the island, hence there is no compelling need to revive the plant. However we have written to government about this,” he said.
When launched, Naripaiyur plant was hailed as Asia’s first and the local population was thrilled. “This plant is still capable of achieving its potential. But we have had problems with the private contractor and maintenance is an issue,” said a worker at the plant.
According to Tamil Nadu Water and Drainage Board sources, many of the smaller plants are also not functioning or are running below par. “In most of these projects, contractors come out with nice reports but the end result - potable water - takes a back seat. These plants often run into trouble because of maintenance issues,” said a TWAD official who did not wish to be identified.
Further, the villagers who get treated water from Naripaiyur plant don’t drink it but use it for other purposes. When the plant was launched, iron pipelines were used and they corroded. “The water supplied was slightly yellowish in colour and people got scared. Though the pipes were changed to PVC later, the fear among the villagers stayed,” explains S Thangam who runs a shop in Naripaiyur.
The plant staff also confirm that villagers are scared of drinking the water. “The water is as good as packaged drinking water we get in shops but people are scared of it,” another worker said.
For their part, environmentalists are apprehensive of the rejected water (discharge) of desalination plants being released in ecologically sensitive areas like the Gulf of Mannar. “Desalination plants should be the final option in areas where fresh water sources are not available at all”, says Naveen Namboodiri, a Bangalore-based marine biologist.
He said that Ramanathapuram coast is rich in coral reef with thriving marine life. “The discharge water which is denser due to higher salinity will settle in the sea bottom affecting coral reef and sea grass,” he warned.
