AWWA ACE54499

This research examined a biological treatment system to remove perchlorate from waters, in which the perchlorate-degrading microorganisms are physically separated from the water being treated by a microporous membrane, thus minimizing potential microbial contamination of the finished water. The process is solely based on diffusion and maintaining a pressure difference across the membrane is not necessary. A perchlorate-reducing mixed culture was enriched from a wastewater treatment plant for this study. The results show that the diffusion coefficient of perchlorate through the membrane is significantly smaller than that of perchlorate in water. Biodegradation testing using immobilized biofilms has shown excellent perchlorate biodegradation. The perchlorate to chloride ratio, was found to be about one, indicating good reliability of the reactor design. The interference of nitrate and total dissolved solids (salinity as NaCl) has been investigated and the results show that high nitrate and salinity levels negatively impact perchlorate biodegradation. Includes 16 references, tables, figures.