Study On Treating Domestic Wastewater And N₂O Reduction In Denitrifying Phosphorus Removal Processes

In nowadays, the level of the nitrogen and phosphorus discharge lead to eutrophivation questions seriously. With the standard of the wastwater discharge controlled, the nitrogen and phosphorus removal become more important questions. Denitrifying phosphorus removal which could removal notrogen and phosphorus simultaneously, using the same carbon source is a new prominent technoque, and it is particlarly suitable for treating low C/N wastwater. However, several studies have reported that denitrifying phosphorus removal process could produce a lot of nitrous oxide(N2O). Therrfor, effective control of N2 O metabolism and emission from denitrifying phosphorus removal process is great importantce and attracts increasingly more attenction.In this study, the denitrifying phosphorus removal was achieved in a SBR reactor which was used to treat municipal sewage and with nitrate as electron acceptor, and N2 O production characteristics during this system. In order to reseach the mechanism and influence factors of the N2 O production, a series studies was operated, and N2 O reduction strategies were evaluated.1) The denitrifying phosphorus removal was achieved in a SBR reactor which was used to treat municipal sewage and acetate, the nitrate and phosphorus concentration were both lower than 1mg/L in enfluenc water. Using FISH method to analysis the population of PAOs at the first 120 day. The results showed that population PAOs reched 11% of the total bacteria at 120 day.2) The effect of different electon acceptor on denitrifying phosphorus removal process: a lab-scale DEBPR culture with 11% PAOs was used with different electron acceptors(O2, NO2-, NO3-), the phosphorus uaptake rates between 90 min were 19.1、16.5、12.6mg P/L·h. N2 O was accumulation when nitrate and nitrite as electron acceptor. The N2 O accumulation accounted 23.7%, 2.3% of TN under nitrite and nitrate system.3) Among many factors that can affect the denitrifying phosphorus removal metabolism of PAO when it utilize nitrite as electron acceptor, this resarch focused on the way of adding nitrite situation, COD concentration, p H conditons. The resuts showed that the reduction of N2 O production was successfully achieved via fractionated adding nitrite, higher COD concentration influenct and higher p H conditions.