Study On Moving Bed Biofilm Reactor Application In Town Wastewater Treatment Plant

Based on the technique of submerged filter and biological fluidized bed, Moving-Bed Biofilm Reactor (MBBR) has been developed as a new, high efficient biofilm wastewater treatment process recently. Compared with activated sludge process, MBBR has many advantages, such as high treatment efficiency, long sludge age, less surplus sludge and no sludge filamentation bulking and so on. The operational effect of Moving-bed Biofilm Reactor (MBBR) and Activated Sludge reactor under the identical condition was studied in this research.1) The results showed that the average removal efficiency of COD in MBBR was 90.9%, similar to that in Activated Sludge reactor under the volume loading rate of 1.2kgCOD/m³d, however the removal efficiency of ammonia nitrogen in MBBR was unstable and the average value was only 52.1%, lower than that in Activated Sludge reactor under the loading of 0.12kgNH4⁺-N/m³d. The lower efficiency of ammonia nitrogen removal in MBBR may be that Oxygen was limited to nitrify in the biofilm under the same lower energy input according to the results of nitrogen balance.2) The attached biomass and the suspended biomass varied periodicity in the MBBR and the biomass in AS was maintained 2.5～3mg/l by arranging sludge; the observed growth rate of biomass in the MBBR was only 0.24gVSS/gCOD, less than 0.45gVSS/gCOD in Activated Sludge reactor, which meant excess sludge of MBBR was obviously lower than that in Activated Sludge reactor. MBBR possesses the complex biocommunity phase and the characteristics such as high efficiency, stable effluent quality and endurance of shock loading.3) When the substrate concentration and dissolved oxygen were non-limiting factor, the carbon removal rate of the epiphytic microorganism, the suspended microorganism in MBBR and the activated sludge in AS were 0.464gCOD/gVSS·h, 0.574gCOD/gVSS·h, 0.389gCOD/gVSS·h; And the ammonia removal rate were 0.01 gNH₄⁺-N/gVSS·h, 0.009 gNH₄⁺-N/gVSS·h, 0.008 gNH₄⁺-N/gVSS·h. 4) Reduce the pH and dissolved oxygen concentration has no influence on the effluent COD concentration in MBBR and AS. And have little influence on the effluent ammonia in MBBR, but have enormous influence in AS.