The Study on Membrane Fouling and Optimization Operating Conditions of MBR Bio-reactor with Different Membrane Materials
|School||Lanzhou Jiaotong University|
|Keywords||Membrane bioreactor Membrane fouling Pollutants removal The optimal|
The different material from the membrane module, due to the material, pore size, and manufacturers of different performance in handling the same wastewater out of the separation characteristics of the membrane water flux, contamination resistance, water flux attenuation coefficient may vary, the present topics based on the the MBR reactor design principle, exploration and the development of a technology that is reasonable, economically viable membrane bioreactor membrane bioreactor on Submerged Membrane Bioreactor for different membrane materials in domestic sewage run situation, and explore optimal operation of the sewage treatment effects and mitigation of membrane fouling, and explore the appropriate operating conditions and process parameters to improve the processing capacity and operational stability of the membrane module to provide a reference for the project to promote the use of. Experimental study showed that: the degree of structure of the film formation of the different membrane materials contaminated layer is different. 1 # PP membrane fouling better than 2 # PVDF membrane. Flux stepped incremental approach, two different membrane materials critical flux, the the draw # PP film critical region 5 ~ 6.25L / (m to 2 · h), 2 # PVDF membrane the critical region for 8.76 ~ 10.51L / (m ~ 2 · h). In order to optimize the MBR operating conditions, the subject of the orthogonal experimental research results show that the measured critical flux available. Analysis of influencing factors on membrane fouling sludge concentration (MLSS) and extracellular polymeric substances (EPS), we can see that the # 1 film and # 2 film pressure growth rate is consistent with the sludge concentration trends # PP film growth rate less than 2 # PVDF, the different material from the membrane module at the same operating conditions, the different speeds of the film pollution; MLSS control, sewage water, water, and membrane module forms and treatment effects, and processing capability should be considered, etc. set, while maintaining the sludge load at a relatively low level in order to achieve optimum treatment effect. EPS total amount of the mixture higher than the supernatant, indicating that the film in the mixture more polluting tendency, the content of the polysaccharide in the mixture and was significantly higher than the protein, the polysaccharide is a hydrophilic polymeric substance, more easily attached in the film hole and on the surface of the gel layer is formed to block the membrane pores, reduce the effective filtration area of ??the membrane, resulting in the flux decreased formation of irreversible membrane fouling. EPS is the cumulative impact of the degree of contamination of the membrane. Under the conditions of the test, the SVI values ??within the normal range, the sludge activity and settlement performance and EPS of content the SVI into a negative correlation. Sewage removal of different materials membrane comparative test study and investigate the removal mechanism obtained under the conditions of this experiment, two different materials membrane module in the average COD removal efficiency of 85 % of ammonia nitrogen removal performance is roughly the same at 98%; turbidity removal efficiency can reach 98% or more, the difference is not great, and the effluent turbidity water reuse standards completely superior to the National Renewable 1 # PP film major pollutants removal efficiency is slightly better than the 2 # PVDF membrane. By orthogonal test program to study the membrane flux, suction time, stop pumping the operating parameters of time and the amount of aeration on membrane fouling, the results show that if the membrane flux is maintained below the critical flux, sludge particles are not readily available in membrane surface aggregation deposition membrane suction pressure remained stable, membrane fouling does not occur or is developing very slowly; shorter suction time or extend the moratorium on time and increase aeration volume will help slow down the membrane fouling, considering the size of the water production and film run long-term stability, draw the best combination of operating conditions for the best combination of operating conditions drawn under the test conditions in the test conditions: membrane flux L / (m to 2 · h), suction time 8min, stop pumping time 2min aeration rate of 0.6 m 3 / h. Membrane flux of the film suction pressure growth rate in the four factors, followed by suction time, stop pumping time, the minimum amount of aeration.