A comparison of pilot-scale photocatalysis and enhanced coagulation for disinfection byproduct mitigation

Document Type



This study evaluated pilot-scale photocatalysis and enhanced coagulation for their ability to remove or destroy disinfection byproduct (DBP) precursors, trihalomethane (THM) formation potential (FP), and THMs in two Arizona surface waters. Limited photocatalysis (/m3) achieved reductions in most of the DBP precursor parameters (e.g., DOC, UV254, and bromide) but led to increased chlorine demand and THMFP. In contrast, enhanced coagulation achieved reductions in the DBP precursors and THMFP. Extended photocatalysis (/m3) decreased THMFP once the energy consumption exceeded 20 kWh/m3. The photocatalytic energy requirements for THM destruction were considerably lower (EEO = 20–60 kWh/m3) than when focusing on precursor destruction and THMFP. However, rechlorination increased the total THM (TTHM) concentration well beyond the raw value, thereby negating the energy benefits of this application. Enhanced coagulation achieved consistent 20–30% removals of preformed THMs. Outstanding issues need to be addressed before TiO2 photocatalysis is considered feasible for DBP mitigation; traditional strategies, including enhanced coagulation, may be more appropriate.


Advanced oxidation; Disinfection and disinfectants; Disinfection byproduct; Enhanced coagulation; Photocatalysis; Trihalomethanes; Water — Purification — Coagulation; Water — Purification — Photocatalysis; Water — Purification — Trihalomethane removal


Environmental Engineering | Environmental Health and Protection | Environmental Sciences | Natural Resources and Conservation | Water Resource Management


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Publisher Citation

Daniel Gerrity, Brooke Mayer, Hodon Ryu, John Crittenden, Morteza Abbaszadegan, A comparison of pilot-scale photocatalysis and enhanced coagulation for disinfection byproduct mitigation, Water Research, Volume 43, Issue 6, April 2009, Pages 1597-1610, ISSN 0043-1354, 10.1016/j.watres.2009.01.010.

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