New tech plant to quench villagers' thirst

Imagine one litre of desalinated water for as low as 4 paise! For reality to seep in, the Bhavnagar-based Central Salt and Marine Chemicals Research Institute (CSMCRI) has developed brackish water reverse osmosis (RO) membrane based on thin film composite (TFC) technology.

Talking to Business Standard, director of CSMCRI Dr P K Ghosh said, "There is lot of dumping of international membranes. What works in America may not be suitable here. The constant improvements in permeation rate have enabled us to fabricate indegeniously built cost effective plants."

"Our new membrane technology and further plant upgradation in 2003 have brought down our cost by almost 50 per cent," Ghosh said.

CSMCRI had set up its first improved indigeniously developed RO membrane based on TFC technology in Mocha near Porbandar in Gujarat and after running it successfully for two years it was handed over to Gujarat Water Supply Board. The plant has an output of 1,800 liters per hour and caters to the need of some 2,000 villagers.

In a bid to facilitate remote villages and also to address special situations after natural calamities where no electricity is available, the institute embarked on the development of animal powered desalination technology. Ghosh said, "This was world's first 'oxen powered desalination plant'."

"We have, to a great extent, dispelled the myth that RO plants are unsuitable for Indian villages. CSMCRI has set up a number of desalination plants in villages of Gujarat, Rajasthan and Tamil Nadu and the plants are operating satisfactorily. CSMCRI has also set up plants in the Barmer and Car Nicobar Air Force bases to serve the defence forces.

"Our membrane modules give over 90 per cent salt separation and the permeate output is 300-400 liters per hour and 1200-1500 liters per hour for 4" and 8" diameter modules, depending on feed water salinity and operating pressure employed," Ghosh said. "Today our 1,200 litres per hour and 2,500 litres per hour plants for treating brackish water can be fabricated for Rs 6.5 lakhs and 9.5 lakhs, respectively," he said.

The institute has entered into a tie-up with Gujarat State Fertilizer Company, Vadodara for setting up an integrated plant. "The project will take 3-6 months to accomplish. This will not only address drinking water issue of the area but also manage saline water residue effectively," he said.

Initially, starting with four villages under the collabration, we are likely to set up many more RO plants, Ghosh maintained. CSMCRI recently made its foray into seawater desalination based on a novel 2-stage desalination design with its brackish water membrane. Two prototype units "" 1000 LPH capacity have been set in Ramanathapuram district and are working satisfactorily, he said .

The capital cost of each plant is around Rs 11 lakhs and the cost of water is 9-10 paise per liter of which the power cost is around 60 per cent. "One of the key areas about which we have so far been maintaining silence is regeneration of R-O modules once they stop functioning. We have successfully developed technology for brackish water," Ghosh said.

"CSMCRI has recognised the fact that RO is not just about taste and desalination but can do away with other harmful impurities such as arsenic and fluoride. Plans are afoot to set up several plants in areas of Andhra Pradesh, whihc is severely affected by the problem of fluoride in ground water. The Institute is also in discussions with the government of West Bengal to install RO units that can simultaneously address the problem of salinity and arsenic," Ghosh said.

A one million litres pre day RO unit for treatment of tertiary treated sewage water has recently been installed at Chennai Petroleum Corporation Ltd.