Comparison of advanced oxidation processes for the removal of natural organic matter

This study examined the impact of UV, ozone (O3), advanced oxidation processes (AOPs) including O3/UV, H2O2/UV H2O2/O3 in the change of molecular weight distribution (MWD) and disinfection by-product formation potential (DBPFP). Bench-scale experiments were conducted with surface river water and changes in the UV absorbance at 254 nm (UV254), total organic carbon (TOC), trihalomethane and haloacetic acid formation potential (THMFP, HAAFP) and MWD of the raw and oxidized water were analyzed to evaluate treatment performance. Combination of O3 and UV with H2O2 was found to result in more TOC and UV254 reduction than the individual processes. The O3/UV process was found to be the most effective AOP for NOM reduction, with TOC and UV254 reduced by 31 and 88%, respectively. Application of O3/UV and H2O2/UV treatments to the source waters organics with 190–1500 Da molecular weight resulted in the near complete alteration of the molecular weight of NOM from >900 Da to <300 Da H2O2/UV was found to be the most effective treatment for the reduction of THM and HAA formation under uniform formation conditions. These results could hold particular significance for drinking water utilities with low alkalinity source waters that are investigating AOPs, as there are limited published studies that have evaluated the treatment efficacy of five different oxidation processes in parallel.

► The impact of AOPs on the change of natural organic matter and it molecular weight was studied.
► Ozone or UV coupled with H2O2 resulted in greater TOC removal than the individual process.
► The combination of ozone and UV was the most effective AOP for NOM removal.
► O3/UV and H2O2/UV had the largest impact on molecular weight transformation.