Design And Research Of The New Combined Membrane Bioreactor

Membrane bioreactor is a new water treatment technology combined a membrane separation unit and the biological treatment unit. Submerged membrane bioreactor has many advantages such as obvious treating efficiency, less sludge production and small floor coverage. The study and application has been received extensive attention, especially for medical sewage treatment. The concentration of effluent suspended in the MBR water is very low, so the untreated bacteria and viruses are easier to be killed without protecting. However, the application of membrane bioreactor is still subject to membrane fouling, leading to less flux, cleaning more difficult, inconvenient operation and management.To solve the above problems existing in current technology, this article explores a new technology combined the membrane module and other biological treatment. Combine the features of each technology, Design the new combined membrane bioreactor. The technology combined by membrane, inverted A2/O and the biological oxidation process. Design the size of membrane bioreactor based on the theoretical knowledge and the existing conditions, then product the equipment and put into operation.The aim of this paper was to solve these above problems. This paper has investigated the combination of membrane and other biological technology, and absorbed the advantages of other treatments and designed the new membrane biological reactor. According to the sticking time of water and other conditions, and worked out the size of reactor and made it.The test wastewater was taken from the 2nd affiliated hospital of Dalian, to ensure stable quality and sometimes would be adjusted accordingly, Raw water SS is 200~300 mg/L, COD is 400~600 mg/L, TOC is 200~300 mg/L, TN is the 90~120 mg/L, TP is 3~5 mg/L, and faecal coliform is about 1.7×108 MPN/L. Seed sludge was collected from the sludge thickener of Dalian Chunliu sewage treatment plant, and then cultivated in acclimation.The SMBR is divided into anoxic zone, anaerobic zone, oxic zone, settling zone, biological contact oxidation (BCO) zone and membrane module zone and the capacity is 12.48 L, 12.48 L, 28.08 L, 14.82 L, 16.25 L and 30.66 L respectively. After reactor startup through a series of test, the aerobic reaction aeration pond identified as 0.1 m3/h, biological contact oxidation pond aeration is 0.08 m3/h, aeration membrane area was 0.15 m3/h, and the prime HRT for the membrane bioreactor was 7.73~8.68 h. The experiment program was adjusted continuously. The results showed that the eliminating efficiency of pollutants with the new combined membrane bioreactor could be perfect and the removal rates of COD, TOC, TN, TP, SS exceeded approximately 90%, 85%, 80%, 90% and 99%, respectively. The process of the volume load is about 2.2 Kg COD/ (m3.d), have a good shock load, the membrane bioreactor has so efficiently removal of the pollution index is the result of the interaction processing units.After two months experiment, the removal rate of TP increased gradually, the removal rate of TP in inverted A2/O is 1~2 mg/L. The measures are regularly discharge the sludge from the sedimentation tank and FeCl3 coagulant dosage in order to enhance the removal of phosphorus rate of trial. The result demonstrated that the prime quantity of FeCl3 dosage was 33mg/L.After 70 days of operation, it showed that there was little change in transmembrane pressure and always kept the following under 0.06 MPa. The membrane flux decrease and the growing drop substantially. To ensure the membrane bioreactor steady and operate effectively, cleaning membrane by 0.1% NaClO and 0.2% H2SO4 to and the membrane flux recovered to more than 96%.