Study On Effects Of Cyclic Changing Environment On Denitrifying Phosphorus Removal In SBR

In this paper, SBR and two-sludge SBR were used to study on effects of environment on denitrifying phosphorus removal. The conclusions in SBR are as following:(l)In anaerobic/anoxic/aerobic processes, under the NO3-N concentration in the anaerobic initial stage is of 2.08,7.60,39.65,46.56mg/L, respectively, the efficiency of denitrifying phosphorus removal is 90.3, 89.7, 60.7, 12.2%. Generally, a higher NO3-N concentration in the anaerobic is profitable. In anaerobic/anoxic processes, the HRT for anaerobic is 20, 60 and 180min, respectively, the released phosphorus conclusions is 24.8,32.4 and27.9mg/L. Too short or long HRT for anaerobic both reduce to the phosphorus release. The better HRT for anaerobic is about 60min.(2)In anaerobic/anoxic/aerobic processes, under the [NO3-N]= 25mg/L, the HRT for anoxic is 60min; and under the [NO3-N]= 40mg/L, the HRT for anoxic is 90min. Too short anoxic leads to nitrate remnant; and too long anoxic leads to phosphorus release.(3)Both in anaerobic/anoxic/aerobic(A/A/O) processes and in anaerobic/aerobic/anoxic(A/O/A) processes, Induced DNPA does not disappear.The conclusions in two-sludge SBR are as following:(4)Nitrogen removal in tow- sludge systems depends on the volume exchange ratio, under the volume exchange ratio is 60%, 70 %, 80%, respectively, the nitrogen removal efficiency is 73 %, 78 % , 100 %, respectively. But the limit of this ratio is mainly formed by the sludge volume index(SVI).(5)Under the condition of [PO4-P]<30mg/L: C/P=35, the ratio of denitrifying phosphorus removal is 49%; C/P=21, the ratio of denitrifying phosphorus removal is 37%; C/P=20, the ratio of denitrifying phosphorus removal is 34%. Generally, the higher C/P is the higher ratio of denitrifying phosphorus removal. But under the condition of [PO4-P]>50mg/L, C/P=14, the ratio of denitrifying phosphorus removal is 65 %. In the high phosphorus concentration, carbon demand is tending to reduce following the phosphorus concentration rising.