Disinfection By-Products in Reclaimed Wastewater Effluents

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Pristine water supplies are being threatened by population growth, changes in climate dynamics, and increasing water demands by economic activities. In recent years, southern parts of Alberta and Saskatchewan have been affected with mild drought conditions that could be aggravated in the future by shrinking glaciers and snow packs in the Rockies that feed many of these region's rivers. Areas that are experiencing severe water drought and scarcity (i.e., Southern California, Texas, Florida) are already developing and implementing technologies to augment their water resources from wastewater effluents. Recycled wastewater for potable reuse requires multi-step treatment process with disinfectants applied at the beginning and the end of the process to effectively control microbial pathogens. Disinfectants can also unintentionally react with other constituents to form disinfection by-products (DBPs), some of which are shown to have chronic toxicity effects. Because effluent organic matter is significantly different from natural organic matter found in rivers and lakes, disinfectants can produce a different suite of DBPs (known and unknown), with possibly higher toxicity. With no guidelines specific for wastewater derived-DBPs, long-term exposure to recycled water might pose an increased human health risk. The overall purpose of my research program is to investigate the formation of DBPs from disinfected wastewater effluents and evaluate the removal of DBP precursors by current and new treatment technologies in a globally one-of-a-kind full-scale experimental wastewater and potable reuse research facility. To this end, this research program will develop new and highly sensitive analytical methods to accurately measure toxic DBPs (e.g., developing methods for iodinated DBPs at ng/L, evaluate new sample preservation techniques that minimize DBP degradation), determine a comprehensive DBP speciation from disinfected wastewaters, characterize the formation mechanisms of wastewater derived DBPs, and assess the toxicity of high-quality recycled water produced from different treatment schemes. This program utilizes an interdisciplinary approach that involves analytical chemistry, toxicology, engineering, and water chemistry with efforts to address the growing concern of water sustainability for future generations.