Construction and validation of catalyst-based biofiltration reactors for the treatment of disinfection by-products in drinking water

ABSTRACT The wide application of disinfection technology in drinking water treatment leads to the formation of potentially harmful disinfection by-products such as trihalomethane (THMs) and haloacetic acid (HAAs), which poses a long-term risk to public health. Traditional treatment methods are often difficult to completely remove these stubborn compounds. To solve this problem, a new type of catalytic enhanced biofilter reactor (CBR) was developed, and disinfection by-products (DBPs) were efficiently removed by synergistic catalytic oxidation and biodegradation. Two high-performance catalysts, FeOx/C (mixed-valence iron oxides, mainly γ-Fe2O3 and Fe3O4, supported on activated carbon) and Mn-TiO2, combined oxidative activity with biocompatibility, enabling the disruption of the stable structure of DBPs and enhancing its biodegradability. The reactor adopted a unique layered design comprising a catalytic packing zone and a biofilm-active zone and operated under intermittent aeration conditions. The reactor adopts a unique layered design, including catalytic packing area and biofilm-active area, and operates under intermittent aeration conditions. The experimental results show that compared with the traditional biofilter, the catalytic biological synergistic system significantly improves the removal efficiency of THMs and HAAs. The system achieved optimal performance under neutral to weakly alkaline conditions (pH 6.8–7.5), with the optimal dissolved oxygen (DO) concentration experimentally determined to be 3.5–4.5 mg/L during the stable operating period, compared with 2.0–4.0 mg/L during the start-up period (days 0–14). The long-term operation for 30 days confirmed the stability of the system, and the chemical oxygen demand (COD) and ammonia nitrogen (NH4+ -N) decreased continuously. In this study, an innovative, efficient, and sustainable DBP advanced purification technology for drinking water is proposed, which has broad application prospects in practical engineering applications.