Impact of influent ammonia concentration on partial nitrification of biological sand filter and kinetics

Abstract

Abstract The impact of influent NH4 +/-N concentration on partial nitrification performance was investigated in a biological sand filter. The removal kinetics model of NH4 +-N in partial nitrification-sand filter was established and its accuracy was verified. The results showed that the NH4 +-N removal rates and NO2 −-N accumulation rates stabled at about 60% and 94% respectively and the effluent NO2 −-N/NH4 +-N ratios were 1.20~1.39 when the hydraulic load was 1.0 m/d and the influent NH4 +-N concentration was 45~50 mg/L, indicating that the sand filter had good partial nitrification effect, and the effluent quality basically met the theoretical influent demand of anaerobic ammonia oxidation. The kinetic model of NH4 +/-N removal in sand filter could be described as Sh /S 0=exp(-1.0033S 0 −1.1337 h) when the influent NH4 +-N concentration was 10.2~61.3 mg/L. The model had high accuracy and could provide scientific guidance for effluent quality prediction and optimization design.