Abstract
The influence of addition of sodium hypochlorite and sodium bisulfite to reverse osmosis (RO) process was examined quantitatively by parallel tests of several pilot-scale UF+RO units. The differential pressure of RO elements and modified Biofilm Formation Rate (mBFR) clearly showed that the addition of these chemicals could be the trigger of the biofouling. In addition, chemical free pretreatment processes of RO are now being established according to the levels of the seawater quality measured by the rapid and easy biofouling risk assessment method which was newly devised.
