SWRO Desalination

It seems that  use of the design of Direct coupling of UF with RO  facilitates   the    intermediate feed tanks , pumps and cartridge filter are eliminated, simplifying the process and layout with reduced maintenance   on frequent replacement of cartridge filters and servicing of associated infrastructure.    There are Desal plants using this Design especially   in Adelaide    (628mld)  /2002   and Perth(300mld) and recently commissioned in SIngapore Keppel Marina East     Desalination plant(137mld). MEMCOR CS Membranes of EVOQUA used for pretreatment and claims  to have achieved  the specific power consumption of 2.10 kWh/cu. m of water produced. There are modular containerised plants also. Really this is great  . In such case , why  this  is   not  widely adopted.?     Besides,   it is   learnt that   many of the   marine micro algae  which  grow excessively when there is Algal Bloom can not withstand pressure more than 0.5 bars  and  hence algal  the cells would break down under pressure     or vacuum  and release    easily   biodegradable organic  compounds.  This would facilitate growth and formation of   Biofim  on the   SWRO membranes .This film would foul the membranes and thus resulting in reduction of plant production within weeks from the beginning of algal Bloom. How this problem is addressed In the absence of Cartridge filters which would otherwise protect the  SWRO membranes from the damaged particles, regards Yuvaraaj Freelance Consultant (Retired . Chief Engineer,i/c;/Chennai Metropolitan Water Supply& Sewerage Board,Chennai,.India