I fully agree with the view of Prof. Biswas that desalination is going to play a major role in mitigating water scarcity issues around the world, especially in the coastal areas. Concerns about carbon footprint and brine discharge are also valid. In addition to higher salinity of brine discharge, thetypically used chemicals such as biocide, coagulants and antiscalants also are potential threat to the enviroment.   As majority of desalination and plants are based on reverse osmosis (RO) process (more thermal desalination are being replaced due to higher energy consumption), discarded RO membranes which are removed from RO plants poses major threat to environment. These RO membranes are made of different polymers and recycling is presently difficult. It is estimated that even for very conservative annual replacement rate of 10%, a one million m3/d production plant shall discard more than 8000 standard 8  inch SWRO membranes alone. If we suppose all exisiting desalination plants (more likely in near future due to low power consumption) are based on RO, annually more than 800,000 RO membranes will be discarded.  This huge number is really going to be a problem unless we address this issue and find solution in either developing innovative desalination technolgy or by finding economic way to reuse or recycle the discareded RO membranes.

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I fully agree with the view of Prof. Biswas that desalination is going to play a major role in mitigating water scarcity issues around the world, especially in the coastal areas. Concerns about carbon footprint and brine discharge are also valid. In addition to higher salinity of brine discharge, thetypically used chemicals such as biocide, coagulants and antiscalants also are potential threat to the enviroment.

 

As majority of desalination and plants are based on reverse osmosis (RO) process (more thermal desalination are being replaced due to higher energy consumption), discarded RO membranes which are removed from RO plants poses major threat to environment. These RO membranes are made of different polymers and recycling is presently difficult. It is estimated that even for very conservative annual replacement rate of 10%, a one million m3/d production plant shall discard more than 8000 standard 8  inch SWRO membranes alone. If we suppose all exisiting desalination plants (more likely in near future due to low power consumption) are based on RO, annually more than 800,000 RO membranes will be discarded.  This huge number is really going to be a problem unless we address this issue and find solution in either developing innovative desalination technolgy or by finding economic way to reuse or recycle the discareded RO membranes.