The Application Of A New Moving Bed Biofilm Reactors In Sewage Treatment Plant Upgrading And Modification

Pollution of water environment in China is worsening and the demands on the sewage treatment plant effluent quality are more and more highly. Currently, a lot of urban sewage treatment plant’s discharge standard is still in a B standard, and some of them even couldn’t reach the stable sewage treatment effect, which sewage treatment plant effluent quality needs to be improved. The new technology of moving bed biofilm reactor (MBBR), which has a good using at home and abroad sewage treatment plants, hasn t be researched and used extensively. This article takes Y county sewage treatment plant upgrading and modification projects for instance, analysing the modification and applications of MBBR process.Y County sewage treatment plant using the treatment process of Orbal oxidation ditch, which implement the water quality of "Discharge standard of pollutants for municipal wastewater treatmentplant"(GB18918-2002) Level B standards. According to the urban development planning of Y County and the environmental protection department s demanding that protect the important basin, Y County should upgrad and modificate the sewage treatment plant to an A standards from a B standards before.The transformation of the two ideas,have been got through the analysis of the structure parameters and water quality of inlet and outlet of the sewage treatment plant water.The one is to improve the hydraulic load and needn’t expansion. Another one is to expand volume which could increase hydraulic loading of the entire sewage treatment plant. Above all, two schemes of the upgrading and modification projects just as follows:Option One:Orbal oxidation ditch+coagulation, sedimentation, filtration processes;Option Two:MBBR integrated complex reactor+coagulation, sedimentation, filtration processes.Comparing the two options analysis, the option two is the best programs in technical and economic terms. In order to verify its feasibility in engineering applications, we had been to do a small scale experiment for simulation of the transformation programs. The results show that the startup time of MBBR biofilm technology is longer than other Activated sludge methods.During the Start and operation, gas water ratio and dissolved oxygen concentration must be adjusted according to different degree of membrane hanging degree. After membrane hanging successfully, the system removal rate of COD, TN and ammonia nitrogen is high, and the treatment effect is stable.Debugging and running taking two different stages along with the progress of the upgrading and modification project. When the first group of structures debugging runs, the temperatures is suitable, and the film is easy to hang, which runs well. While the other groups starts in the winter, the temperatures is too low and hang biofilm difficulty, which hang successfully by adjusting the operating mode and the applied nutrients, etc. When the system run normally, the outlet water, treatment effect and the capacity of impact loading are better than before.This article is the study of using MBBR process to upgrading the Orbal oxidation ditch, which is an epitome of MBBR process application, which could be a reference for other object that upgrad the sewage treatment plant by using MBBR progress.