Effect of temperature on anaerobic ammonia oxidation performance of bio-sand filter

Abstract

A bio-sand filter was used to as a reactor for the start-up of anaerobic ammonia oxidation (ANAMMOX), and the effect of temperature change on ANAMMOX performance and its recoverability were investigated. The results showed that the start-up of ANAMMOX could be successfully achieved in 92 days in the bio-sand filter under the temperature of 30°C. When the average influent concentrations of NH4+-N and NO2−-N were 19.7 and 25.5 mg/L respectively, the average removal rates of NH4+-N, NO2−-N and TN were 98.1%, 98.6% and 91.5% respectively. The bio-sand filter could maintain high efficiency and stable performance of ANAMMOX under the temperature of 20∼35°C. When the temperature dropped to 15°C for 7 days, total nitrogen (TN) removal rate dropped to 83%. When the temperature was reduced to 10°C for 11 days, the removal rates of NH4+-N, NO2−-N and TN were dropped to 73.5%, 72.7% and 68.5% respectively. After resuming the temperature to 30°C for 19 days, the ANAMMOX activity could basically resumed to the original. When the temperature increased to 40°C for 9 days, both the NH4+-N and NO2−-N removal rate decreased to 86.5%. The ANAMMOX activity be gradually recovered after resuming the temperature to 30°C for 5 days. The effect of low temperature on the ANAMMOX performance of bio-sand filter was more significant than that of high temperature, and the time needed for recovery after the shock of low temperature was longer.