Assessment of the Potential Presence of Chemical Contaminants in Water Produced by Desalination System
Reverse osmosis (RO) systems are being used widely for treatment of brackish and saline water. Aside from their relatively high energy cost and concerns associated with brine disposal, most utilities consider desalination a reliable technology. In fact, the high quality of water produced by RO systems is touted as an advantage of desalination relative to other water sources such as wastewater effluent.
RO membranes effectively remove most organic compounds from water, with rejection values over 95% for dissolved organic carbon and most chemical contaminants of regulatory concern. However, lower removal rates have been reported for neutral, low molecular weight compounds such as NDMA, chloroform, and bromoform. The concentration of these and other neutral, low molecular weight compounds in water produced by desalination systems will depend on the source water quality, the design of the desalination system, and the nature of the distribution system.
This collaborative project between PUB, National Water Research Institute, UC Berkeley, and the WaterReuse Foundation has the following objectives:
- To conduct a preliminary assessment of the occurrence of contaminants of concern (bromoform, NDMA, algal toxin) in water produced by desalination systems
- To identify conditions in which the contaminants of concerns are most likely to occur as well as different approaches for controlling the compounds
- To identify issues that merit further study to improve predictions of the concentrations of concerned contaminants
- To decrease the uncertainties associated with construction of desalination systems, and to anticipate public health concerns that may arise during the process of permitting desalination plants.
This project will provide a structured evaluation of seawater for potential presence of chemical contaminants in water produced by RO desalination plants.