Application Research Of MBBR On Treatment Of Urban Sewage

With the continuous development of society and economy, the discharge of industrial wastewater and urban sewage has been increasing dramatically. Thus, it is extremely urgent to improve the treatment efficiency of municipal sewage treatment plant. In this work, MBBR system was designed and employed to treat the urban sewage. Through the preparation of new biological suspended materials, optimization of process parameters and the pilot study, the MBBR system was proven to be the feasible to deal with urban sewage. The main results of the present work were summarized as follows:1. HY-MC1 carrier was prepared by adding the attapulgite improving the structure and material properties of polyurethane biological carrier. The results showed that compared with unmodified polyurethane carrier, HY-MC1 had better material density, skeleton density and specific surface area, which facilitated the coherence of microorganism on the solid surface and improved the growth rate of bio film.2. By using HY-MC1 as carrier, a MBBR system was designed and applied to remove pollutants from urban sewage. The key factors, such as sludge reflux ratio, aeration rate and hydraulic residence time significantly had a great effect on removal efficiency of organic pollutants. When the sludge reflux ratio reached 1/8, the removal ratio of COD, NH3-N, TN increased to 21%,6% and 25%, respectively. The removal ratio of COD, NH3-N and TN in the effluent of the system was about 70.8%,91.7% and 38.3% respectively, under the conditions of aeration intensity being 350L/h and HRT being 12h.3. The pilot study of MBBR system showed that by applying of MBBR system to the modification of the urban sewage treatment system, the effluent COD, NH3-N and TN was under 50 mg/L,8 mg/L,7-12 mg/L, respectively. This indicated that the COD, NH3-N, TN of effluent could satisfy the A level of discharge standard of pollutants for municipal wastewater treatment plant.