Research On The Membrane Coupled With A Bioreactor Filled By Bamboo Charcoal For Bath Wastewater Treatment

Applications of Membrane bioreactor(MBR) technology have advantages in wastewater reuse, but membrane fouling seriously limiting the expansion of MBR’s applications. The mixture of nature in MBR is an important factor affecting water quality and membrane fouling, so research on membrane fouling mechanism and control methods of extracellular polymeric substances(EPS) and soluble microbial products(SMP) in sludge mixture has become an important content of applied research of MBR. Making Bathing wastewater as raw water, charcoal as a filler fixed bed in MBR system. The effect of treatment wastewater, the formation characteristics of EPS and SMP at different Volume load, hydraulic retention time(HRT) and aeration strength and their membrane fouling in long running were studied, using SEM to express the phenomenon of membrane fouling. Specific results are as follows:(1)Reactor for COD, ammonia nitrogen and LAS stable removal efficiency, which can be achieved in the effluent water reuse standards; TP removal effect of fluctuations is relatively large, needs to be further improved. Sewage treatment system optimal parameters were as follows: volume load 1.2kgCOD /(m3·d), gas-water ratio 16: 1, HRT 5h. At this COD, ammonia, LAS and TP removal rates can reach 90.7% maximum, 94.1%, 96.9% and 45%.(2) Compared to the low volume load, high volume load the EPS content and protein content increased, polysaccharide reduced. Under high volume load, SMP content and protein content increased, polysaccharide first increase and then reduced. This shows that the EPS and SMP in polysaccharide protein compared to susceptible microbes, SMP compared with EPS susceptible microbes.(3) All of the accumulations of EPS and SMP in MBR increased and polysaccharide in EPS no growth but decreased. Compared to the Low aeration, EPS content growth rate is not obvious in high aeration, the protein in EPS increased slightly, after reaching a certain value. Polysaccharide’s content decreased with increased aeration. The amount of SMP in high aeration is more than SMP content in low aeration, in which polysaccharide’s content increased and the protein content decreased. This shows that increasing aeration to exceeding a certain value, prompting the microbes secretes more SMP, or more EPS converted into SMP. Polysaccharides in EPS and proteins in SMP are susceptible to utilization by microbial.(4) Compared to the low HRT, high HRT the EPS content and protein content increased, polysaccharide in EPS also increased. IN high HRT, SMP content was lower than low HRT, which’s polysaccharide and protein are lower. This shows that SMP was easier than EPS to be degraded, so were protein and polysaccharide.(5) Rising volume load, the biomass increased in the reactor, and membrane fouling rate rised. Membrane fouling rate and the content of EPS and SMP was positively related to relationship. SMP and EPS of polysaccharide, protein can damage to the film, Proteins are the main factors of membrane fouling, membrane fouling rate was related to the ratio of protein and polysaccharide. If gas water ratio rise, biomass in the reactor will increase, take the lead in reducing membrane fouling speed after bigger. Membrane fouling rate and the content of SMP and polysaccharide in the EPS, polysaccharide in the SMP was positively related. The SMP and polysaccharide is the main factor causing membrane fouling. Membrane fouling rate decreases with the increase of aeration, but not aeration has been increasing can reduce membrane pollution. When the aeration for more than a certain value, membrane fouling will increase instead. Increase the HRT, biomass in the reactor and membrane fouling rate decreases. Membrane fouling rate are negatively related with EPS content, was positively related with SMP. This illustrates the SMP is the main factor causing membrane fouling, polysaccharide and protein of SMP aggravate membrane fouling. Membrane fouling rate decreases with the increase of HRT, Thus, improve the HRT is an effective way to control membrane fouling. After the membrane is contaminated, the outer surface of the membrane adsorption of microbial floc and inorganic pollutants, in which large concentration of pollution layer forming dense structure. Pollutants into the inner surface, so that the membrane’s surface rough, a lot of holes in the surface is blocked, causing the membrane flux decline.