Denitrification of drinking water using a hybrid heterotrophic/autotrophic/BAC bioreactor

Abstract

Abstract The performance of a hybrid heterotrophic/autotrophic/BAC bioreactor (HHABB) for denitrification of drinking water was studied in continuous mode for several months to determine the optimal conditions. The HHABB was consisted of three compartments: ethanol heterotrophic part (EH-part), sulfur autotrophic part (SA-part) and BAC-part (including anoxic and aerobic sections). The experiments were conducted at six runs with NO3 − loading rates ranged from 0.36 to 1.45 kgN m−3 d−1, C:N ratios 0.53 and 0.70 and approximately constant NO3 − concentration of 30 mgN l−1. At lower NO3 − loading rates (0.36 and 0.72 kgN m−3 d–1), the C:N ratio 0.53 provided high denitrification efficiencies (96–99%) with very low effluent DOC and trihalomethane formation potential (THMFP) concentrations of 0.33–0.50 mgC l−1 and 26–41 μg l−1, respectively. In contrast, at No3 − loading rate 1.07 kgN m−3 d−1, an increase in C:N ratio to 0.70 was required to achieve suitable results. The aerobic BAC-part showed suitable efficie...