Seawater Desaliantion Membrane Biofouling
Featuring Sunny Jiang, Ph.D.
Associate Professor, Department of Civil and Environmental Engineering
The Henry Samueli School of Engineering, UC Irvine
Free and open to the public
Desalination of seawater has been used or currently considered as an important alternative to dwindling drinking water supplies in water-scarce coastal regions worldwide. However, seawater reverse osmosis (SWRO) membrane biofouling presents a major challenge to desalination industry. Our research effort has focused on identifying the trigger and causes of biofouling in SWRO. The results showed a quantitative relationship between algal blooms and decreases of SWRO performance suggesting changes in microbial growth and composition following algal blooms. Nutrient addition experiments using biofouling monitors indicated the positive response of biofilm density on RO membranes. Molecular analyses showed that diverse group of marine bacteria were present in the biofilm of the RO membrane. This biofilm bacterial community was different from bacterial community on the cartridge filter, immediately upstream of the RO feed water, suggesting cartridge filter was not the source of biofouling bacteria in the feed stream. The source of the biofouling bacteria on the RO membrane was from both free-living bacteria in the intake water and endpoints that associate with phytoplankton based on the microbial community fingerprinting analysis. The bacterial community on the cartridge filters from different geographical locations including S. Cal, N. Cal, Tampa Bay, Israel, West and South Australia showed very different bacterial community profiles. However, RO biofilm communities from different locations were fairly similar, showed several cosmopolitan species of bacteria and dominant the bacterial community. This result suggests there may be a common culprit of membrane biofouling. This study lays the foundation for the understanding membrane biofouling and contributes to the development of strategies to combat biofouling.