Meeting the demands of society and industry through indigenous technology
The miracle of our asymmetric semi-permeable membrane in the form of thin film composite and the reversal of natural osmotic flow of solvent occurring in micron size cells on account of externally applied pressure in excess of the osmotic pressure has resulted in installation of reverse osmosis desalination plants all over the country. The first requirement of Reverse Osmosis (RO) process to occur efficiently is the appropriate chemical structure of the polymer material from which the asymmetric membrane is made and the method of generating porous structure into the membrane. The second requirement is the application of sufficient pressure to over come the osmotic pressure of the saline solutions. Our RO membrane technology has been developed based on these fundamental aspects.
Our Institute pioneering activities in membrane science and technology began way back in1969, when the first ever asymmetric membrane from cellulose acetate polymer was developed in India. The membrane was later configured in tubular and spiral forms of different sizes in length and 1" diameter which led to the successful demonstration of first ever indigenous RO brackish water desalination plants of 10,000 to 15,000 l/d capacity at various places in the country.
Our continuous search for making better and durable membrane led to the development of thin film composite (TFC) membrane for desalination of brackish water. The TFC membrane is a two-layered polysulfone-polyamide membrane structure supported on a non- woven polyester fabric. In this structure, an ultrathin polyamide barrier layer of about 0.2 μm is formed/coated on the surface of a microporous polysulfone that has been cast onto a porous non-woven fabric. This membrane has given a consistent performance of 95% rejection of total dissolved solids from brackish water containing up to 10,000 ppm of brackishness for which the technology has been developed.
Capabilities of the Discipline
Department has created state-of-the art facilities for membrane development, membrane testing, spiral module development and plant fabrication. In India, the institute is second to none as far as membrane activity and indigenisation of brackish water desalination technology is concerned. From 1969 to 2000, over a span of three decades, our brackish water technology has grown/progressed from a modest 10,000 lpd capacity (20% recovery) to 10,00,000 lpd capacity (70% recovery). We are also focusing on developing appropriate membranes and technologies for removal/rejection of Fluoride, Arsenic, Nitrate, and Hardness ions from drinking water and is on the verge of installing membrane based defluoridation and softening plants in problem areas for water purification. The institute is committed to societal missions for providing safe and hygienic drinking water and has always responded positively/favorably whenever the need arose.
