Effect of Moderate and Room Temperature on Nitrogen Removal in PN-ANAMMOX Process

Abstract

The effect of moderate and room temperature on nitrogen removal rate and microbial community was studied in PN-ANAMMOX process by inoculating mature nitrification membrane and ANAMMOX sludge. The results showed that the PN-ANAMMOX combined process was achieved at room temperature, and the nitrogen removal rate reached 0.5 kg·(m3·d)-1. But the activity of ANAMMOX did not reach its maximum due to the decreased NO2--N production rate, resulting in far lower nitrogen removal rate of PN-ANAMMOX than that at moderate temperature which reached 1.75 kg·(m3·d)-1, and the effluent had poor water quality. When the temperature rose, the NOB grew rapidly, the PN process became unstable, but the activity of NOB could be effectively controlled by increasing the return flow. The results of QPCR analysis showed that the inoculation of AOB and ANAMMOX was not conducive to the growth at room temperature, and part of the microorganisms died. When the environment was recovered to moderate temperature, the corresponding functional microorganisms appeared to grow rapidly. Therefore, suitable temperature should be provided for the microorganisms during the operation of the PN-ANAMMOX combined process.