This study develops a biofouling indicator for seawater desalination using reverse osmosis (RO) membranes in a southern California desalination pilot plant. Chlorophyll is identified as a sensitive indicator for membrane biofouling.
One of the challenges faced by the seawater desalination industry is biofouling of reverse osmosis (RO) membranes.
Traditional water quality parameters such as silt density index (SDI) and the RO feed water turbidity are inadequate at protecting the membrane from biofouling. Therefore this research investigated the environmental and water quality parameters in a southern California desalination plant, in order to develop a set of seawater desalination RO membrane biofouling indicators.
Statistical analysis was performed on data collected onsite over two years. The paper presents the relationships between operation parameters, rain precipitations, total organic carbon (TOC), raw water UV254 absorbance, chlorophyll fluorescence in raw seawater, and the performance loss of the RO desalination process.
The environmental triggers for accelerated RO membrane biofouling were further investigated by developing membrane fouling simulators at the desalination pilot plant. Biofouling was confirmed by confocal laser scanning microscopy investigation of the membrane biofilm and live and dead bacterial cell counts.
The results of this study indicate that biofouling was significantly correlated with water quality changes. Thus, chlorophyll fluorescence measurements can be used as a precursor for desalination membrane biofouling.
