AWWA WQTC71540

A Water Research Foundation Tailored Collaboration project is being conducted to evaluate zero liquid discharge (ZLD) desalination of waters with high concentrations of natural organic matter (NOM). The technical approach involves treating reverse osmosis (RO) or nanofiltration (NF) membrane concentrate to reduce its fouling potential so it can be desalinated in a second membrane application. Concentrate generated from waters with high organic content must be treated for total organic carbon (TOC) removal to prevent organic fouling as well as removal of calcium, sulfate, and silica to prevent inorganic fouling. The research comprises three phases: preliminary analysis to identify concentrate treatment goals; evaluation of concentrate treatment options; and, evaluation of the effect of concentrate treatment on performance of the secondary desalination device. The work is currently in the second phase of evaluation of concentrate treatment options. The treatment processes being evaluated for concentrate treatment are chemical softening, fluidized bed crystallization, activated alumina, MIEX, electrodialysis, and coagulation with ferric chloride. Testing is being conducted on five water sources. The results for one water source are reported here. The final Water Research Foundation report will be published November 2010. Includes reference, tables, figures.