Study On Biological Contact Oxidation To Treat Sewage

In rural areas, most of the families have no provision of drainage ditches and sewage treatment systems, lead to a lot of the untreated sewage discharged directly, not only cause a serious impact on the safety of drinking water in rural areas, freshwater resources and arable land used for life also have adverse effects, serious damage to the ecological environment of the local countryside, making health and economic interests of the peasant masses under serious threat. So for this rural sewage dispersibility of characteristics, it is necessary to design integrated sewage treatment apparatus.An integration of a life wastewater treatment equipment, integrated bio-contact oxidation, including regulation pool, primary sedimentation tank, contact oxidation tank and secondary sedimentation tank are used in this paper. During the test, sewage come from a manhole cover behind the experimentarium in Dalian Jiaotong University. Sludge come from Dalian purple Ling Water Sewage Treatment Co., Ltd. Vaccination hanging membrane is used in testing membrane method. Test by fixing the amount of water, aeration, changing hydraulic retention time and temperature to determine the optimum operating parameters and observe the excess sludge production. Draw the following conclusions during the test:(1)In the early biofilm training period, the removal of COD, NH4+-N and SS are poor, little change in the concentration of sludge. As the gradually mature biofilm, the removal efficiency of COD, NH4+-N and SS are increasing, sludge concentration is decreasing significantly. When the COD removal efficiency is70%-80%, the effluent COD concentration is less than50mg/L, marking biofilm membrane successfully.(2)When the influent COD concentration is100-200mg/L, temperature is22℃, DO is10mg/L, as the growth of HRT, the removal efficiency of COD is increasing. But considering the cost of construction investment issues, the HRT is set to2h, both economical and reasonable.(3)When the influent COD concentration is100-200mg/L, hydraulic retention time is2h, DO is10mg/L,the removal of COD and NH4+-N is gradually increasing from15℃to23℃. Temperature has an effect on the activity of microorganisms. Microbial activity is inhibited when in low temperature, the removal of COD and NH4+-N is poor. When the temperature is rising, the microbial activity recover, the removal of COD and NH4+-N get agood recovery. Therefore, in order to ensure the removal efficiency, the temperature is set to be above20℃.(4)Sludge is discharged, so the equivalent of extending the SRT. The SRT extension increase the number of protozoa and metazoan, extend the food chain. From an ecological perspective, the longer the length of the food chain, the more energy consumption, the less the energy of the bacteria can use synthetic itself, the less biomass. In addition, the predation of protozoa and metazoan, also reduce sludge production, so this test achieve a sludge reduction purpose.