AWWA JAW56399

Perchlorate is a health concern because it disrupts the thyroid gland's use of iodine in the generation of metabolic hormones and could ultimately hinder normal physical growth and development. Because perchlorate contamination of drinking water has only recently come to the forefront, no technology has been established as the optimal treatment process for perchlorate removal. This research evaluated the use of activated carbon filtration to reduce perchlorate concentrations using conventional contact times and without generating a concentrated perchlorate waste stream. Abiotic granular activated carbon filtration experiments demonstrated that perchlorate was removed by ion exchange rather than chemical reduction. Biological reduction of perchlorate in the low-microgram-per-litre concentrations was achieved using biologically active carbon (BAC) filtration. Batch experiments verified the biological reduction and demonstrated that microorganisms in the BAC filter converted perchlorate to chlorate. Study results indicate that BAC filtration has the potential to be very cost-effective and efficient for removing perchlorate. Before BAC filtration can be applied to full-scale perchlorate remediation, however, the process must be optimized with respect to operating conditions and water quality characteristics. The findings described here should help raise the general awareness of promising biologically based technologies, which are already in extensive use in Europe and are making inroads in the United States. Includes 39 references, figures.