Effect of a constructed wetland on disinfection byproducts: Removal processes and production of precursors

The fate of halogenated disinfection byproducts (DBPs) in treatment wetland s and the changes in the DBP formation potential as wastewater treatment pl ant (WWTP)-derived water moves th rough the wetlands were investigated. Wet land inlet and outlet samples were analyzed for total organic halide (TOX), trihalomethanes (THM), haloacetic acids (HAA), dissolved organic carbon (D OC), and UV absorbance. Removal of DBPs by the wetland ranged from 13 to 55 % for TOX, from 78 to 97% for THM, and from 67 to 96% for HAA. The 24-h end 7-day nonpurgeable total organic halide (NPTOX), THM, and HAA formation po tential yields were determined at the inlet and outlet of these wetlands. T he effect of wetlands an the production of DBP precursors and their DBP-for mation potential yield from wastewater was dramatic. The wetlands increased DBP yield up to a factor of almost 30. Specific changes in the DOC precurs ors were identified using C-13 NMR spectroscopy.