Study On Nitrogen And Phosphorus Removal Of Domestic Sewage By Using SBBR

The standard of wastewater discharge was controlled more strictly with the severe eutrophication question occurred. Today, the nitrogen and phosphorus removal technology aimed for eutrophication control has been the study focus in the wastewater treatment area. Denitrifying phosphorus removal is the new prominent biological wastewater treatment technique. The Anaerobic/Anoxic/Oxic(SBBR) system is fundamentally based on the technique of denitrifying phosphorus removal. The main advantage of SBBR system is the possible saving of adding COD and less sludge production and cutdown cubage of the reactor. These characteristics benefit significantly for the municipal wastewater treatment, especially for the low influent C/N municipal wastewater treatment where the lack of carbon effects the nutrient removal efficiency.SBBR technique(Sequencing Batch Reactor of submerged biofilm process) not only has the characteristics of sequencing batch technique but also the advantages of biofilm technology, which change the activated sludge into biofilm with carrier in the reactor on the base of SBR. This paper has researched the new type biological nitrogen and phosphorus removal of SBBR. The experiment operated with stimulant municipal wastewater was carried out. Using the SBBR system to actualize the nitrogen and phosphorus removal simultaneity. Effect of the COD,nitrogen and phosphorus removal was studied using the SBBR system .Based on the steady system, effect of influent COD/TN, concentration of NO3--N , temperature on the nitrogen and phosphorus removal was studied.The system circulate under the Anaerobic/Anoxic/Oxic mode, studying the effect of denitrifying phosphorus removal. The process operating cycle parameters of the SBBR was:120min anaerobic period, 90min anoxic period, 210min aerobic period, 20min precipitable period,10min effluent period. the SBBR reactor under the condition of the temperature was 20～25℃, the hydraulic retention time (HRT) was 26h and the volume load was 0.3kgCOD/(m3·d), the steady system has good capability of denitrifying phosphorus removal, the parameters of influent such as COD, phosphate, ammonia nitrogen concentration were: 378mg/L,8.13mg/L,21.6mg/L, the effluent content were: 60.2mg/L,0.9mg/L,0.54mg/L, the removal efficiency of them in the SBBR system were 84%,88.9%,和97% respectively. The SBBR system effectually resolved the problem which the low COD content lead the nitrogen and phosphorus removal simultaneity under the lack of organics, the experiment testify that the SBBR system has capability of denitrifying phosphorus removal.In the anoxic period, the different NO3-concentration, COD concentration, temperature, C / N ratio have a different impact on denitrifying phosphorus removal. The experiment data show that in the anoxic period,NO3-dosage was 30 mg / L, the phosphate removal is best and the removal rate reached 27%, in this period COD concentration is less than 100 mg / L, phosphate removal rate is higher; the SBBR reactor temperature maintained at 25℃, denitrifying phosphorus removal effect is preferably in the system. Through analyse the C / N ratio of influent water on the impact of removing nitrogen and phosphorus, the C / N ratio of 6 to 10 is best. When the enter water C / N ratio higher than 10, lack of nitrogen lead to incomplete phosphorus ,when the enter water C/N ratio below 6, lead to the phenomenon of excess nitrates, impact on the concentration of effluent TN.