Application Of The Hybrid Membrane Bioreactor In The Treatment Of Municipal Wastewater

The objective of this research is to design a new reactor for improving wastewater reuse and to save water resources. Therefore, a new hybrid membrane bioreactor (HMBR) with suspended carriers of new material and structure was explored. This study was focused on the effect of operating parameters (HRT, SRT, sludge load and DO) on HMBR performance.Under the condition of no sludge discharging, HMBR was operated for about one month to investigate the influence of HRT on HMBR performance. In this run, HRT was controlled in 12h, 10h and 8h. The results showed that no matter how the HRT changed, the removal rate of COD in the system was all above 95%. The effect of HRT on COD removal efficiency was not significant. From the removal rate of NH₄⁺-N in the system, we can see that removal rate of NH₄⁺-N of bio-treatment cell decreased according to the increase of HRT. And membrane can not hold NH₄⁺-N back effectively. The removal rate of Toxic organic compounds (Toluene, Pyridine) increased according to the increase of HRT. Based on an overall consideration of various factors, HRT of 8h was the feasible value for HMBR operation.Under the condition of HRT at 8h, HMBR was operated to investigate the influence of SRT on HMBR performance. In this run, SRT was controlled in 10d, 15d and 20d. The results showed the removal rate of COD, NH₄⁺-N and Toxic organic compounds (Toluene, Pyridine) all increased according to the increase of SRT.Under the condition of HRT at 8h and no sludge discharging, HMBR was operated to investigate the influence of sludge load on HMBR performance. The results showed that the removal rate of COD increased according to the increase of COD sludge load, the removal rate of NH₄⁺-N decreased according to the increase of NH₄⁺-N sludge load, the removal rate of toxic organic compounds (Toluene, Pyridine) decreased according to the increase of the concentration of toxic organic compounds in the influent.Under the condition of HRT at 8h and no sludge discharging, HMBR was operated to investigate the influence of DO on HMBR performance. The results showed that the removal rate of COD increased according to the increase of DO, the removal rate of NH₄⁺-N is highest when DO=2mg/L, the removal rate of toxic organic compounds (Toluene, Pyridine) increased according to the increase of DO.GC/MS analysis showed that there were small amounts of toxic organic compounds produced, but the concentrations were very low.In this thesis there were still experiments of cleaning the membrane treads. And the membrane fouling was visualized by scanning electron microscope. The results showed that after chemical cleaning, the polluted membrane almost appeared the structure of new membrane.