Pre-oxidation Strategies for Improvement of Biofiltration Performance

Abstract

Biofiltration has been shown to reduce the concentration of disinfection by-product (DBP) precursors. Recent studies have examined different methods to increase the rate of organic matter biodegradation during biofiltration. One viable option is to pre-oxidize the complex organic matter into smaller molecules to increase uptake by the microbial communities on the media. This study examined the application of ozone (O3) and ozone+hydrogen peroxide (O3+H2O2) to improve the subsequent removal of DBP precursors via biofiltration. Nitrogen and phosphorus (0.5 mg/L) were added to biofilter influent and their subsequent uptake monitored to ascertain the viability of nutrient supplementation as a biofiltration enhancement strategy, both with and without preoxidation. Both O3 and O3+H2O2 enhanced biofiltration by breaking down high molecular weight humics into smaller, more biodegradable compounds. While O3+H2O2+biofiltration led to higher dissolved organic carbon removal, O3+biofiltration provided better DBP precursor reduction for both THMs and HAAs.