Engineered Biofiltration for the Removal of Disinfection By-Product Precursors, Genotoxicity and Emerging Contaminants

Biofilters have been operated in a passive manner without operator control, but the focus has shifted to the potential for enhancement. This pilot study compared conventional treatment (coagulation, flocculation, sedimentation, non-biological filtration) to passive and engineered direct biofilters for the removal of disinfection by-product precursors, and genotoxic precursors for two different source waters (Lake Ontario and Otonabee River). Additionally, 9 pharmaceuticals and 2 artificial sweeteners were spiked into the pilot to observe the reduction of these emerging contaminants through the biofilters.;Conventional treatment provided superior performance compared to biofiltration for the removal of DBP precursors, but performed equally well with respect to genotoxicity reduction in Otonabee River samples. Lake Ontario water was best treated by filters receiving 0.8 mg/L PACl. Engineered biofilters, enhanced with nutrients or hydrogen peroxide, were typically no better than a passively operated biofilter. The removal of pharmaceuticals and sweeteners was improved with a combination of biological and chemical treatments.