Effects of RO membrane cleaning agents and disinfectants on reverse osmosis membrane performance

Abstract

The level of quality in the water purified by reverse osmosis and utilized during haemodialysis is of cardinal importance. Properly set pre-treatment equipment will definitely extend both life and permeate quality of the RO membrane. Unfortunately, operating parameters like temperature, feed IDS, permeate flow and recovery are susceptible to changes, and fouling of the membrane and element feed path can occur. In this study particular cleaning procedures were carried out to investigate their effects on membrane performance. A particular 6-year-old membrane was chosen for this research project. Current data was normalized and compared to the start-up conditions. Data before chemical treatment was also compared with that collected after treatment. Results achieved by these normalization procedures for the determination of the particular state of the membrane were strange. Reasons could be due to unreliable start up data or some form of correction necessary in the calculations. Further investigations would be needed to explore more deeply these inaccuracies. Comparisons of performance data before and after treatment resulted in a decrease of 0.1 bar in the AP indicating a very slight improvement. This very slight improvement could indicate that the RO membrane was: A. In a relatively good condition and not fouled and scaled to a large extent. B. So much fouled or scaled that no effect was seen by the treatment Monitoring for particular chemical scaling agents was also done by analysing samples from the reject side during treatment every five minutes and on other individual chemical parameters before and after clean. Even these results indicated no abnormal changes before and after treatment. This could also be an indication that there were minimal changes after the cleaning procedure.