City scientists iron out the nuisance material

KOLKATA: A modest project undertaken by a group of Kolkata scientists to solve their kitchen problems could bring relief to everyone.
A unique filtration system developed by scientists of Central Glass and Ceramic Research Institute to remove the iron content in the water of their housing colony is starting to make waves in cities awash in water pollution.
The scientists put their heads together to develop the ceramic-based system after seeing their families suffer because of the extremely high iron content in the water at their SIRSA housing complex in Dhakuria. Utensils rusted, clothes got discoloured and frayed, and there was a chronic rash of skin infections.
“We tried all kinds of ways to circumvent the problem, even reviving a defunct tubewell; but high content of iron colloids was insurmountable,� said a tenant.
Then the resident scientists then got to work. After a series of failures, the eureka moment came when they discovered that a ceramic-based membrane was effective in removing iron colloidal. This formed the core of a technology that involves pumping water into a tank for oxidation and then passing it through multi-element membrane modules under high pressure.
The plant can process 5,000 litres a day, and the cost comes to a mere 20 paisa per litre. “Considering that it gives you clear drinking water, this price is nothing. The plant removes iron to almost zero detection levels,� said CGCRI director Dr H.S. Maity. “It also removes turgidity and pathogens from water, though we are not making an official claim about it at the moment,� said head of CGCRI ceramic membrane division Dr Shibaprasad Bandyopadhyay.
“WHO norms for drinking water stipulate a purification level of at least 0.3 ppm. Ours is the only method that can achieve this level with the raw water we have.�
The Department of Science and Technology has asked the institute to start planning a project for the North-east. The plant can easily be installed in housing complexes. “It costs just Rs 3 lakh. If residents are charged even 25 paisa a litre, the cost of operation will be easily recovered,� Bandyopadhyay said.
Safe Water
_ Soluble iron is oxidised into iron colloids and particles
_ Ceramic membranes of pore size smaller than iron particles are developed
_ Water is passed through the membrane under pressure
_ Iron particles are filtered out and form a deposit
_ Membrane needs to be cleaned at periodic intervals