| Based on the problems of expensive cost and membrane-fouling of the membrane bioreactor, the industrial cloth was utilized as the membrane materials to develop a new submerged dynamic membrane bioreactor(DMBR) in this paper. The denitrogen efficiency and operation process of DMBR were investigated.The five filter clothes were utilized as the membrane material to develop a dynamic membrane bioreactor (DMBR). The results showed the removal efficiencies of COD, NH4+-N and TN by the DMBR with the 24μm polyester short-staple cloth were over 90%, 80% and 48%, respectively. The DMBR with the 24μm polyester short-staple cloth had a higher recovery membrane flux than the other DMBR. The polyester short-staple cloth was attributed to the best material of the DMBR.?The effects of different influent C/N ratios on the denitrogen efficiency were investigated in the DMBR with the polyester short-staple cloth. A simplified activated sludge model(ASM-CN) was proposed, which based on the activated sludge model No.1(ASM1). The results showed that the effluent concentrations of COD, nitrite and nitrate of DMBR were under 50 mg/L, 0.25 mg/L and 0.70 mg/L, respectively. The removal efficency of COD was over 85% in the different C/N ratios. When the C/N ratio was over 6.75, total nitrogen and ammonia removal was 50% and 60%, respectively. With the ratio of C/N increased, the removal efficiency of ammonia and total nitrogen was better. Based on the ASM-CN model, the simulated value of COD was closed to the measured value. When C/N ratio was over 5.04, the simulated values of total nitrogen and ammonia were proximately the measured value.The denitrogen efficiency was investigated in different dissolved oxygen (DO) condition, the characteristics of membrane fouling were dicussed too. The results showed that when the concentrations of DO were more than 0.5 mg/L, the concentration of effluent COD was about 16.67 mg/L. When the DO was 3.0-3.5 mg/L, the effluent concentration of ammonia and total nitrogen was about 15 mg/L, 30 mg/L, respectively, and the removal efficiency of total nitrogen was about 35.24%. The value resistance of cloth and dynamic membrane was 2×106 m-1 and 4.32×107 m-1, respectively. The resistance of dynamic membrane was the main resistance in the DMBR.In order to improve the denitrogen efficiencies of DMBR and relieve the membrane-fouling, the DMBR was investigated with the addition of granules activated carbon(GAC), and compared to the MBR. At the same time, the two bioreactors were simulated by the the ASM1. The membrane flux of DMBR and MBR were 20 L/(m2·h) and 10 L/(m2·h). The membrane pressure of DMBR was always at 3500 Pa, the membrane pressure of MBR was over 10000 Pa at the beginning, but repaidly increased to 48000 Pa. The operation period of MBR, 10% GAC-MBR and 20% GAC-MBR was 3 d, 7 d, 7 d, respectively. The DMBR was cleaned once in the 90 d operation time. The operational time was prolonged with the addition of GAC in the two bioreactors. The removal efficiency of COD of them was over 85% in the two bioreactors. The effluent concentrations of ammonia nitrogen and total nitrogen of GAC-DMBR was 7 mg/L and 14 mg/L, respectively, the denitrogen efficiencies were better than the DMBR. Using the ASM1 to simulate two bioreactors, the results showed the simulated value of water quality equaled to the measured value. |
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