Research On Characterisitcs Of The Five-bore Fiber And Application In Treating Dyeing Wastewater By MBR

Because of the supporting structure in the centre, the five-bore fiber developed by our seminar has the characteristics of high strength, high impact resistance, which extend the life of the fiber. But its distinctive structural characteristics of five-bore and feature of treating wastewater are not clear. Therefore, the main task of the subject is to focus on the structural characteristics of the five-bore fiber which in advanced treatment of the dyeing wastewater by MBR. The research lasts seven months, which included spinning and application. Contrast single-bore fiber analysis of the five-bore fiber supporting membrane performance characteristics of the basic membrane on operation of the TMP, the decline of specific membrane flux, the composition and variation of membrane resistance, Continuous and stable operation of the water quality, the concentration of proteins and polysaccharides in the EPS-containing solution abstracted by disodium EDTA method were measured, and the correlation between the composition of EPS and membrane fouling was discussed. Furthermore, analysis methods, such as SEM, spectral scanning, were used to analyze and measure the pollutants on the membrane surface. As mentioned above, conclusions were made as follows:(1) The average membrane flux, retention to BSA, rupture tensile strength and porosity of the five-bore fiber obtained through measuring are 468L/(m2·h),64.7%,8.97MPa and 84.59% respectively. The key of the fiber's larger flux and higher retention rate are rooted in the five-hole self-supporting structure with low porosity in support layer and dense outer surface.(2) The Js and Rm of the five-bore fiber in clean water measured after the component is made are 9.83L/(m2.h.kPa) and 3.64×1011,which are inverse.The critical flux of the five-bore fiber measured through flux step incremental approach is 21 L/(m2·h).(3) The three factors of HRT, aeration intensity and MLSS were studied. The optimal process parameters of were acidified hydrolysis-MBR obtained:HRT of hydrolysis acidification tank was 28h, HRT of MBR was 20h, aeration intensity was 0.2 m3/h, MLSS was 5000mg/L. CODcr, turbidity, UV254 and color removal values of five-bore fiber and single-bore fiber were 92.5%,0.36NTU,0.58 and 82.5%; 89.8%,0.58NTU,0.70 and 81.7%.(4) Run in the sub-critical flux, membrane fouling can be divided into two phases, the I stage duration of five-bore fiber is 46h which is longer than the single-bore fiber, theΔP/Δt为0.016 kPa/h. Conclusion from membrane resistance analysis is that Rg, Rm, Rp and Re ratios of five-bore fiber are 2%,14%,33% and 51%. The membrane Rm in the total membrane resistance is accounted for 10% or more, cake layer resistance and concentration polarization resistance as the main membrane resistance are accounted for 70% or more in membrane resistance, and the cake layer resistance is greater than the concentration polarization resistance. The resistance of the membrane surface composition of rate has nothing to do with the fiber structure(5) The concentrations of both SMP and combined EPS keep growing up since the start in the MBR system. In the combined EPS of aerobic sludge, protein shows a higher concentration than polysaccharide. Comparison five-hole membrane and single-bore fiber can be found, protein and polysaccharide of five-bore fiber are always smaller than single-bore fiber.(6) Through the UV-visible scans influent to effluent and all along way water in acidified hydrolysis-MBR, the chromaticity could be removed greatly by hydrolysis acidification tank. SEM analysis of the membrane surface and the cross section indicate that membrane surface is covered with a layer of film and observed particulate pollutants attached to the membrane surface, the pollutants can't be seen obviously in the cross section, which also shows the contribution of membrane fouling mainly come from cake layer on membrane surface.