Use of Ozone in Water Reclamation for Contaminant Oxidation
Year Released: 2014
Funding Partners: Bureau of Reclamation, California State Water Resources Control Board
Total Investment: $1,344,529.47 (Cash: $333,712.47, In-Kind: $1,010,808)
Principal Investigators: Shane A. Snyder, Ph.D., University of Arizona, Urs von Gunten, Ph.D., Eawag: Swiss Federal Institute of Aquatic Science and Technology, Gary Amy, Ph.D., King Abdullah University of Science and Technology, Jean Debroux, Ph.D., Kennedy/Jenks Consultants, and Daniel Gerrity, Ph.D., Southern Nevada Water Authority, Trussell Technologies, Inc., UNLV
Increased public awareness, potential human health effects, and demonstrated impacts on aquatic ecosystems have stimulated recent interest in pharmaceuticals and personal care products (PPCPs) and endocrine-disrupting compounds (EDCs) in water and wastewater. These trace organic contaminants (TOrCs) are largely unregulated, but their ubiquity has necessitated studies on the efficacy of various treatment processes for their removal and/or transformation. Since municipal wastewater is considered the primary source of PPCPs and EDCs in the environment, expansion and optimization of wastewater treatment processes may be the most efficient strategy to mitigate the potential effects of these contaminants. Ozone is a unique option because its efficacy is similar to that of high-pressure membranes and advanced oxidation processes.
Goals and Objectives
The project characterizes the use of ozone in wastewater treatment applications with respect to bulk organic matter transformation, contaminant oxidation, microbial inactivation, and the formation of disinfection byproducts and other transformation products. A secondary objective was to evaluate the synergism between ozone and biological filtration, including biological activated carbon (BAC) and soil aquifer treatment (SAT), in the context of potable reuse applications. Finally, the project compared the treatment efficacy of ozone- and UV-based oxidation and ultimately developed cost estimates for these individual unit processes and corresponding advanced water treatment trains.
This project characterized the use of ozone in wastewater treatment by evaluating bench-scale dose-response relationships for 19 TOrCs and 3 surrogate microorganisms (E. coli, MS2 bacteriophage, and Bacillus spores) in 10 secondary wastewater effluents. In addition to contaminant and microbial treatment objectives, a number of additional ozone-related parameters were evaluated during the study. Pilot- and full-scale experiments were also performed to verify the efficacy of ozonation in large-scale systems and as part of advanced treatment trains. The project concluded with an Association for the Advancement of Cost Engineering (AACE) Class 4 cost estimate for a variety of advanced treatment processes and hypothetical treatment trains.
Findings and Conclusions
Ozone can be implemented as a standalone oxidation process or it can be supplemented with hydrogen peroxide. The addition of H2O2 is generally intended to drive the formation of OH radicals in order to reduce structural footprints, reduce disinfection byproduct formation, or target more recalcitrant compounds. However, ozone alone is fully capable of generating OH in wastewater applications due to side reactions with effluent organic matter.