[Start up and maintain of nitritation by the inhibition of FA and FNA].
In order to treat the digested sludge dewatering liquor bypass and reduce influent ALR of wastewater treatment plant, the startup and maintenance of nitritation was investigated in an A/O reactor. NOB activity was inhibited and nitritation was stated up successfully by increasing the influent ALR (in N, the same below) step by step from 0.23 kg/(m3 x d) to 0.78 kg/(m3 x d), in spite of normal temperature, long SRT and high DO concentration. Due to the deficiency of alkalinity in influent, nitritation could be maintained steadily by the associated inhibition of free ammonia (FA) and free nitrous acid (FNA). The nitrite accumulation ratio always kept at above 90% during the period of maintaining nitritation for 30 days, and correspondingly the average concentration of DO was higher than 2 mg/L. The nitrite accumulation ratio did not decline even if the average DO concentration increased to 4.8 mg/L, which demonstrated that high DO could not destroy the nitritation built by the associated inhibition of FA and FNA. The concentration of FNA at the last chambers was increased by reducing the influent ALR in order to enhance the inhibition of FNA. The nitritation was still maintained for two months although the inhibition of FA was weakened. But the nitritation was destroyed completely in 3 days after the inhibition of FNA was eliminated, which showed the inhibition of FNA to NOB was very critical to maintain steadily nitritation.
Han
Xiao-Yu
XY
Key Laboratory of Beijing for Water Quality Science and Water Environmental Recovery Engineering, Beijing University of Technology, Beijing 100124, China. hxy-hit@163.com
Zhang
Shu-Jun
SJ
Gan
Yi-Ping
YP
Wang
Hong-Chen
HC
Peng
Yong-Zhen
YZ
D000641:Ammonia / Q000302:isolation & purification / Q000378:metabolism*; D019149:Bioreactors; D009608:Nitrous Acid / Q000302:isolation & purification / Q000378:metabolism*; D012722:Sewage; D014865:Waste Disposal, Fluid / Q000379:methods*
D012722:Sewage; D000641:Ammonia; D009608:Nitrous Acid