The Feature Studies On The Sequencing Batch Biofilm Reactor (SBBR) For Municipal Wasteater Treatment

Trial project is based on existing sewage treatment process in Shanxi Province, proposed an improved technology (SBBR process) and optimization program to improve wastewater treatment efficiency. The output water quality to achieve "urban sewage treatment plant discharge standard" (GB18918-2002) in an A standards for wastewater reuse, implying water resource utilization.In this experiment, the actual urban sewage water for the test.The study on the sequencing batch biofilm (SBBR) process for treating municipal wastewater biofilm formation and start the process, SND phenomenon, operating cycle, seperately.Mainly inspected removal efficiency of the five indicators: COD , NH3-N, TN, TP, SS in SBBR process under different operating cycles.During the two weeks were hanging membrane phase, using inoculation hanging membrane. The removal rate of COD based on raw water that is 80%, and late periods for low influent organic concentration, but the removal rate has been stable at 60%.The removal rate of NH3-N reached to 80% , and late has been very stable.Based on above, deemed that the hanging film success, determining the best filler filling ratio is 15.4%. During stable operation stage, COD and NH3-N index for the study, investigated the "initial rapid adsorption" phenomenon, confirmed the existence of this phenomenon in the reactor.The reseach on the impact of DO and C/N ratio on the phenomenon of SND. Run cycle by: inflow→aeration(7h)→outflow, for a trial period is 8 hours.When out of the water content by way of the whole exchange, replacement volume of 12L, the water temperature is 24.2℃, the DO concentration between the 1.0 ~ 2.5mg/L, C/N ratio is between 12 to 13, the study achieved better effect on simultaneous nitrification and denitrification, TN removal efficiency can be maintained above 50%. Meanwhile, the study found that DO≤2mg/L, the accumulation of NO2-N emergenced, when DO was 1mg/L, the nitrite accumulation rate(NO2--N/NOx--N)was 61.5%, reached the maximum.Aerobic (4h) - hypoxia (1h) in intermittent aeration mode, adding glucose to adjust COD values in the influent, where the dosage is 3~4g, a cycle of 12 hours. Effluent COD values stabilized below 50mg/L, the effluent NH3-N value between 9~20mg/L, the TN value between 10~25mg/L, the TP value between the 0.4~5.5mg/L, the SS value between 25~150mg / L.Operation cycle with the former, adding the two middle carbon source, the total dosage is 1.5g. Effluent TN value of 10~16mg/L, effluent NH3-N value of 3~11mg/L, TP value of 0.1~1.0mg/L. Capared with the initial one-time saving of approximately half of the carbon source dosage, and the water effect is better. At this point, determine the best discharge ratio is m=1/2, TN value≤15mg/L, to achieve an A standard.Consider the phosphorus problem, based on the original period to extend the aeration time.Under the run mode of the discharge ratio is 1/2 and adding carbon intermediate, the effluent COD, NH3-N, TN values have been within the standard basicly, TP and SS is still not stably compliance. Against the phosphorus problem, experiment showed that the optimal anaerobic phosphorus time is 1~1.5h and the aerobic time is above 3~3.5h, could meet the maximum phosphorus uptake, then TP removal rate was reached 75.92%. Discharged 2 Liters sludge volume, the phosphorus was the best, the TP removal rate was 77.7%, the effluent TP value of 0.439mg/L, has been within the standard range, now the TN removal rate was 60.1%.Finally, the test compared with the SBR and SBBR process on treatment effect. Before the 5 hours aerated reaction, the NH3-N value in SBBR was lower about 10mg/L and the removal rate was higher about 20% than SBR process; after the 5 hours, the both sides had the similarly removal rate. In the same water load, to achieve the same treatment effect, SBBR process can shorten the aeration time, and save operating costs.