Inhibition of Nitrite on Denitrifying Phosphate Removal Process
Poly-phosphate accumulating organisms (PAOs) could use nitrite as electron acceptor but poorly function compared to oxygen in phosphorus removal. The authors try to figure out the different effects on anoxic and aerobic P-uptake by environmental factors (pH, temperature and nitrite concentration) and identify the real inhibitor in anoxic metabolisms. 26 sets of batch tests were designed, using highly concentrated PAO cultures. The results show pH influence on P-uptake activity are similar in anoxic and aerobic tests, but temperature has strong effects on aerobic P-uptake activity compared to anoxic. pH values were are correlated linearly with nitrite reduction and P-uptake rates instead of FNA. Also, weak correlation between FNA and two reaction rates shows pH rather than FNA is likely the main inhibitor. P-uptake rates are correlated linearly with nitrite reduction and PHA consumption rates. It’s possible that intracellar concentration isn’t affected by FNA diffusion and don’t affect intracellar P-uptake process.