Tuesday, November 6, 2007 - 2:15 PM
230-13

The Effect of Halide Concentrations on the Advanced Oxidation Process Treatment of Membrane Concentrates from Municipal Wastewater Recycling for Brackish Water Aquaculture.

Janel E. Grebel1, William A. Mitch1, Joseph J. Pignatello2, and Monica W. Lam1. (1) Chemical Engineering, Yale University, Mason Lab 313b, 9 Hillhouse Avenue, New Haven, CT 06520, (2) Soil and Water, Connecticut Agricultural Experiment Station, 123 Huntington St, P.O. Box 1106, New Haven, CT 06504-1106

Municipal wastewater recycling is often practiced to supplement drinking water supplies in arid portions of the world. Reverse osmosis (RO) membrane treatment is applied to remove the elevated concentrations of salts and organic contaminants in these waters. Unfortunately, RO treatment generates a waste brine that constitutes nearly 30% of the RO treatment unit influent. One of the most attractive options for the beneficial reuse of these saline brines is brackish water aquaculture. However, such reuse necessitates the removal of organic contaminants that may be harmful to fish or their consumers. Advanced oxidation treatment processes are an attractive treatment option because hydroxyl radicals generated by this process are minimally selective, enabling the removal of a broad range of potential contaminants. However, halide ions, particularly bromide, represent the major hydroxyl radical scavengers in these waters, in the process generating a series of bromine-containing radicals. This research examines whether these bromine-containing radicals reduce process efficiency by simply scavenging hydroxyl radicals, or whether they contribute to the oxidation of organic matter. In addition, this research examines whether reactions of these bromine-containing radicals result in the formation of potentially toxic brominated organic products. Preliminary results indicate that when samples are treated under hydroxyl radical generating conditions in the presence of bromide ion we observe significant incorporation of bromine into riverine natural organic matter and the formation of brominated phenols from phenol.