Study On The Processes Of Novel Membrane Bioreactor (MBR) Coupled With Nylon Woven Fabric Filter

In recent years, membrane bioreactor (MBR) has been widely used in wastewater treatment to achieve higher effluent quality, which is often difficult to be effectively met by conventional activated sludge process. The advantages of MBR are high quality water, simple flow, lower excess sludge production, fewer area occupied and so on. Membrane bioreactors been developing for several decades and always broadening its application fields, and has attracted more and more attention. However, their widespread applications are hindered by their elevated energy consumption and the high costs of investment for the membrane modules. In this study, we investigated a modified an improved MBR system that utilized a cost effective woven fabric instead of nonwoven as the filter material in MBR modules for solving this problem. The fabric bioreactor. Besides simple flow, fewer area occupied et al as MBR, FBR also has the advantages of low cost, low energy consuming and high intensity. The new-style process is a promising technology for small-scale wastewater treatment, and has great significance to study.In this study, the performance of synthetic domestic wastewater treatment was evaluated in the FBR with different pore diameter nylon woven as filtration material at same operating conditions, in order to analyze whether the different pore diameter nylon as a filter medium is feasible. This study investigated the treatment performance of simulated domestic wastewater with the FBR, almost all effluent water quality can meet our hope. In order to optimize the process parameters of FBR, for its wide application of FBR in wastewater treatment, the factor that affects the effluent efficiency and the factor that affects the stable operation of FBR were analyzed in this paper. This study also discussed the filtration mechanism and resistance of the filter. The main study content and result are shown as follows:(1) The results show that effluent of FBR with mesh number of 300 is with some sludge, so the nylon woven of 300mu can not as a fabric filter material for FBR. FBR with different mesh number nylon woven of 400mu and 500mu has good removal efficiency for contamination. System CODcr removal efficiencies are all over 92%, and the average removal efficiencies are 90.32% and 92.89%respectively. FBR with different mesh number nylon woven of 400mu and 500mu have good removal efficiency for UV254, Turbidity and SS. By comparing the 400mu and 500mu nylon woven bioreactor, experimental datas show that little difference between the two nylon woven fabric. FBR with mesh number of 400 nylon fabric filter has greater flux than 500 mesh nylon fabric filter.(2) The FBR with 400mu nylon woven eliminated suction pumping by using a gravity head in the membrane filtration of the effluent over the entire operational period of 41d. The results show that FBR with t mesh number nylon woven of 400mu has good removal efficiency for contamination. System CODcr removal efficiency is 93.68%, the average CODcr of effluent is 104mg/L; turbidity removal efficiency is 90.31%, the average turbidity of effluent is 22.6NTU.(3) FBR has high resistance to sludge bulking. In conventional settling tank, sludge filamentous bulking was the most common problems that cause activated sludge settling problems and a deterioration of effluent quality. In the WFBR, since woven fabric as the solid-liquid separator could filtrate the level of suspended solids in the sludge supernatant, the effluence when sludge filamentous bulked was better than before.(4) The optimum operating condition of FBR with 400mu nylon woven is that:the optimum HRT is 20h, the optimum MLSS is about 7100mg/L, the optimum BOD loading rates is from 0.09 to 0.12 kg BOD/kg MLSS/d.(5) The results of filtration mechanism of FBR shows that the solid and liquid are separated by nylon woven fabric through mechanical sieving, superficial adsorption, bridging flocculation。(6) The total filter resistance with 400mu nylon woven is 0.21114 m-1, which is lower 11 orders of magnitude than the conventional membrane filtration resistance. The inherent resistance of 400mu nylon woven is 2.3005*10-5 m-1, which is lower 16 orders of magnitude than the conventional membrane filtration resistance. The filter cake accounts for 71.93%of the total resistance. Nylon woven fabric flux recovery after water cleaning and mechanical cleaning is above 90%.