Membrane Bioreactor Nitrogen And Phosphorus Removal Enhanced Research

The main purpose of this thesis is to investigate how to improve the ability of membrane bioreactor in nitrogen and phosphorus removal. Biofilm membrane bioreactor (BMBR) and sequencing batch membrane bioreactor (SBMBR) are studied respectively.For evaluating the efficiencies of a membrane biological reactor (MBR) and a biofilm membrane biological reactor (BMBR) with suspended media, tests were carried out to compare the performances of the two reactors in removing pollutants in domestic water. The result showed that adding suspended medias to MBR improved the ability of MBR not only in organic pollutant removal but also in nitrogen and phosphorus removal, the average percentage of T-Nt TP from 45.5% and 47.2% increased to 57.4% and 71.8%, respectively. BMBR was also found to have higher ability of shock loadings resistant than MBR. The specific flux in BMBR was 0.1 L/h KPa, but in MBR the specific flux decreased to 0.036 L/h Kpa. We also could get that the membrane fouling in MBR was more serious than that in BMBR according to SEM photograph of membrane sections in the two reactors.A membrane bioreactor running in sequencing batch way was developed to investigate nitrogen and phosphorus removal. The characteristics of nitrogen and phosphorus removal and the membrane fouling of the two systems were studied under different ratios of COD to T-N, which was decreased by increasing the ammonia-N in influent. When the COD/TN of influent was as low as 3.8-8.3 and ammonium nitrogen loads was 0.17kgNH4+-N/m3 d, changing the running period and increasing the change ratio, the efficiency of SBMBR in TN and ammonium nitrogen removal could maintain at 67.6% and 93.1%, respectively, while CMBR could not work well. The sequencing batch running way in membrane bioreactor can also reduce membrane fouling.BMBR and SBMBR all not only can improve the membrane bioreactor in nitrogen and phosphorus removal but also can reduce membrane fouling.