Influence Of Nitrogen And Phosphorus Deficience On Activated Sludge System

In order to study the influence of nitrogen and phosphorus shortage on activated sludge system, sequencing batch reactors (SBR) were operated with an anoxic-oxic pattern in parallel with different values of influent COD/N/P. The effects on sludge settleability, nitrogen and phosphorus removal characteristics, effluent quality and flocculate structure were investigated in sequencing batch reactors inoculated with different types of activated sludge and the recovery of activated sludge was investigated with a elevated influent COD/N/P of100/15/3.The effects of N deficiency on activated sludge system were found in the state of nitrogen shortage and phosphorus sufficient. In the premise of inoculating with activated sludge had a good removal effect of nitrogen and phosphorus, when the value of influent COD/N was more than equal to100/2, the activated sludge had good settling properties. When the value of influent COD/N was100/3, filamentous activated sludge bulking occurred. When the value of influent COD/N was more than equal to100/0.75, the removal effect of nitrogen and phosphorus seriously exacerbated. Specific phosphorus uptake amount was below5mg-PO43--P/g-MLSS and nitrification activity was below lmg-O2/g-VSS h-1.The activated sludge system had certain denitrification and phosphorus removal ability at a influent COD/N value of100/2.Specific phosphorus uptake amount was about14mg-PO43--P/g-MLSS and nitrification activity was about1.26mg-O2/g-VSS h-1.With a elevated influent COD/N of100/15, non-bulking activated sludge maintained good settling properties,and the removal effect of nitrogen and phosphorus can’t be obvious recovered in a short period.The effects of N deficiency on activated sludge system were found in the state of nitrogen shortage and phosphorus sufficient. In the premise of inoculating with activated sludge had had a good removal effect of nitrogen and a bad removal effect of phosphorus, When the value of influent COD/N was more than equal to100/1, the activated sludge had good settling properties. When the value of influent COD/N were100/3and100/2, filamentous activated sludge bulking occurred. When the value of influent BOD/N was more than equal to100/1, the removal effect of phosphorus exacerbated with different degree. Specially at a influent COD/N value of100/0.75, specific phosphorus uptake amount was above8mg-PO43--P/g-MLSS. With a elevated influent COD/N of100/15, the settling properties of activated sludge seriously exacerbated and the removal effect of nitrogen and phosphorus can’t be obvious recovered in a short period.The effects of P deficiency on activated sludge system were found in the state of phosphorus shortage and nitrogen sufficient. In the premise of inoculating with activated sludge had had a good removal effect of nitrogen and a bad removal effect of phosphorus, When the value of influent COD/P was100/0.6,the activated sludge had good settling properties. When the value of influent COD/P was more than equal to100/0.4, non-filamentous activated sludge bulking occurred. When the value of influent COD/P was less than equal to100/0.4,the activated sludge system had good denitrification and phosphorus removal ability and nitrification activity reached up to3mg-O2/g-VSS h-1.When the value of influent COD/P was more than equal to100/0.2, nitrite accumulation occurred. The accumulation of nitrate were separately5.40mg-N/g-VSS and4.66mg-N/g-VSS with influent COD/P of100/0.2and100/0.1.With a elevated influent COD/P of100/3,non-bulking activated sludge maintained good settling properties and the settling properties of bulking-sludge seriously exacerbated. The removal effect of nitrogen and phosphorus can’t be obvious recovered in a short period.The effects of N and P synchronous deficiency on activated sludge system were found.In the premise of inoculating with activated sludge had a good removal effect of nitrogen and a bad removal effect of phosphorus, when the value of influent COD/N/P was100/2/0.4,filamentous activated sludge bulking occurred. When the value of influent COD/N/P was100/0.5/0.1,the activated sludge had good settling properties. With a elevated influent COD/P of100/15/3, the settling properties of activated sludge seriously exacerbated.