Effect of FA on Shortcut Nitrification of Dewatering Filtrates in Aged Landfill Sludge
In view of the characteristics of high ammonia nitrogen and low C/N of aged landfill sludge,the two-stage AO-MBR process is used to explore the feasibility of partial nitrification treatment of denatering filtrates of actual aged landfill sludge.On the premise of achieving stable pollutant removal efficiency,the focus is on investigating the impact of free ammonia(FA)on the stability of partial nitrification.The results showed that the nitrite nitrogen(NO2--N)accumulation rate(NNAR)showed a quadratic correlation with FA concentration.At higher FA concentration,the NNAR in the primary nitrification tank(O1)exceeded 50.0％,with a maximum of 76.9％,achieving partial nitrification.The microbial community structure information indicated that the species abundance of ammonia nitrogen oxidizing bacteria(AOB)in the O1 tank was much higher than that in the secondary nitrification tank(O2),and the species abundance of AOB in the O1 tank was more than 10 times that of NO2--N oxidizing bacteria(NOB).The inhibitory effect of FA on AOB conforms to the Haldane model of substrate inhibition kinetics,and the maximum specific proliferation rate of AOB μmax was 0.34 g N/(g VSS·d),the toxicity inhibition constant(Ki)was 143.4 mg/L,and the semi saturation constant(Ks)was 38.3 mg/L.Taking into account the fluctuation of influent water and practical production applications,it is advisable to control the concentration of FA in the system from 40 mg/L to 80 mg/L.This paper provides a reference for the design and operation of future aged landfill sludge dewatering liquid treatment facilities.
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维普
