Experimental Investigation Of Anaerobic Hydrolysis-Binary Biological Contact Oxidation (ABBCO) In Treating Urban Sewage

Binary Biological Contact Oxidation (BBCO) is developed from the traditional biological contact oxidation with the pool divided into two sections. It can give full play to synergy between similar microbial populations, and overcome antagonistic action between different microbial populations, greatly improve the processing efficiency. The BBCO is advantages of short process time, stable operation conduction, resistance to impact load ability, simple operation. But it also has the opposite side with high concentration of suspended solids and low nitrogen removal efficiency. Adding an anaerobic hydrolysis tank in front of the BBCO can improve biological oxidation performance of the sewage, remove most of the SS in wastewater, reduce pollution load for the follow-up biological treatment. The paper makes a research of anaerobic hydrolysis-binary biological contact oxidation (ABBCO) treatment of urban sewage, including the influence of hydraulic retention time, dissolved oxygen concentration, volume load to the pollutants removal rate. It lays foundation for sewage treatment process conditions optimization. The main research contents show bellow.1、This paper probes into pollution degradation process and starting cycle when the system startup at ambient temperature. The result shows that the removal rate of CODcr and NH/-N rise to82.44%(higher than80%) and70.32%. It appears to thick biological membrane both on anaerobic section and aerobic section. When observed by optical microscope, there comes to be an abundance of bacteria, fungi, protozoa and metazoan which has formed a stable micro-ecological system on the packing. It is a sign of hanging membrane successfully. It takes ten days to hang membrane successfully in this reactor.2、Keep DO concentration in5-6mg/L at ambient temperature, then change the water flow to research impact of hydraulic retention time (HRT) on pollutants removal rate when HRT is2hours,4hours,6hours,8hours,10hours. The result shows that the reactor has a most stable treatment effect when HRT is6hours. At this moment, the removal rate of CODcr, SS, NH4+-N are respectively82.40%,91.17%,98.37%, and the output concentration of CODcr, SS, NH4+-N are21.69mg/L,8.91mg/L,0.20mg/L. All of them are lower than the first level of national discharging standard.3、Keep HRT at6hours at ambient temperature. Change exposure volume to research impact of DO concentration on pollutants removal rate when the DO concentration is2-3mg/L,3-4mg/L,4-5mg/L,5-6mg/L. The result shows that the reactor has a most stable treatment effect when DO concentration is5-6mg/L. At this moment, the removal rate of CODcr, SS, NH4+-N are respectively81.74%,92.01%,98.33%, while the output concentration of CODcr, SS, NH4+-N are22.10mg/L,9.97mg/L,0.55mg/L. All of them are lower than the first level of national discharging standard.4、Change the organic load by adding rice water into the wastewater to research impact of organic load on pollutants removal. The result shows that system has a strong organic load capacity. The removal rate of CODcr raise all along when the input organic load ranges from0.90kg CODcr/(m3.d) to3.45kg CODcr/(m3.d). The Maximum removal rate of CODcr, SS, NH/-N are respectively87.11%,89.88%,94.97%, and the output concentration of CODcr, SS, NH/-N are48.92mg/L,13.43mg/L,1.63mg/L. All of them are lower than the first level of national discharging standard.5^The ABBCO has a stable ability to treat urban sewage at ambient temperature. The experimental date shows that the reactor has a most stable treatment effect when DO concentration is5-6mg/L and HRT is6hours. The removal rate of CODcr, SS, NH4+-N are respectively82%,98%,90%, and the output concentration of CODcr, SS, NH4+-N are lower than the first level of national discharging standard. Further more, contrast to the pollutant removal rate contribution value in B, the removal rate contribution value of CODcr and NH4+-N are higher in A, while the removal rate contribution value of SS are lower. The ABBO is advantages of high treatment effect, low operation cost, easy management to treat urban sewage. Setting an anaerobic hydrolysis tank before the BBCO can greatly improve biochemical nature of the sewage. Binary biological contact tank adopts biological belt and Honeycomb packing element as carriers to strengthen organic removal process and greatly improve treatment efficiency.6^Analysis substrate removal dynamics of this process on the base of Underbrush test. According to material consumption balance in the reactor, it is concluded the dynamic model and the relevant dynamic constant. The substrate removal dynamical model of anaerobic period is U=0.0008Se,and the aerobic period is U=73.53(Se-9.47)/857.79+(Se-9.47).