| Manganese oxidizing bacteria is the dominant flora of microbial ecosystem which existsin, according to the nutritional types of bacteria,it can be divided into autotrophic bacteriaand heterotrophic bacteria. When autotrophic bacteria is inoculated in biological filter ofmanganese removal, it becomes the dominant flora;when heterotrophic bacteria is inoculatedof biological, it becomes the dominant flora. Since the two types of manganese oxidizingbacteria have a different way of physiological metabolism and nutrition conditions, as the rawwater quality of biological filter changing, manganese oxidizing filter will exhibit differentstability, this may be the cause of instable running of biological filter.According to the view of above, thorough research is studied in this paper. First ofall,the source, cultivation method,and the result of manganese removal of the two kinds ofmanganese oxidizing bacteria was studied; Based on last step, The following questions werestudied: how to inoculate the two kinds of manganese oxidizing bacteria into a manganeseremoval filter,how to start the biological filter of manganese removal using the two kinds ofmanganese oxidizing bacteria, what is the maturation process and mechanism of biologicalfilter of manganese removal; In the end, influencing factors of the mature biological filter ofmanganese removal as well as its parameters control were studied, a dynamic model ofmanganese removal was established.(1) This experiment gets samples from activated sludge aeration tank which are easyachieved, then inoculated in two different selective mediums, JFM(autotrophic) and modifiedPYCM(heterotrophic), training methods for subculture,after that we achieved two differentspecies of manganese oxidizing bacterias., which cultured cycle are both five days, after sixweeks of acclimatization training, its manganese removal rate reached97.89%and88.49%.Autotrophic bacteria of manganese oxidizing belongs to gram-negative bacteria, similar tosome certain bacterias of Leptothrix, iron Aeromonas, Siderocapsa, Heterotrophic bacteria ofmanganese oxidizing belongs to gram-positive bacteria, similar to some certain bacterias ofLeptothrix, Metallogenium, Hyphomicromium. Under oligotrophic environment, manganeseremoval rate of the two kinds of manganese oxidizing bacteria are respectively41.64%and37.25%,both are not very good, and adding proper nutrition promote the effect of manganeseremoval by the two species of manganese oxidizing bacterias.(2) The two species of manganese oxidizing bacterias which were domesticated wereinoculated with mode of circulating immersion into filter column. Low filtrationrate1.86m/h, low backwash strength6.L(s.m2) were selected to start the biological filter of manganese removal. The experiments using fresh to simulate ground water, under theexperimental condition of the raw water, add the appropriate amount of ammonianutrition,2#filtration column(vaccinate autotrophic bacteria) complete the start process, whenthe raw water is not added ammonia nutrition,1#filtration column (vaccinate autotrophicbacteria)experienced55days of star time is not yet complete.Add the appropriate amount ofammonia nutrition helps to shorten the maturity of biological filter of manganese removalwhich vaccinated autotrophic manganese oxidizing bacteria; raw water without addingnutrition,3#filtration column(vaccinate heterotrophic bacteria) have failed to start; adding15mg/L CH3COONa and0.5mg/L(NH4)2SO4,4#filtration column(vaccinate heterotrophicbacteria) have failed to start;3#filtration column exhibited no manganese removal effect,4#filtration column has a certain manganese removal effect but not satisfied the requirement ofmature biological filter of manganese removal, so either low or high organic carbon content inraw water is not suitable for the start of biological filter of manganese removal whichvaccinated heterotrophic manganese oxidizing bacteria. The surface of Mature quartz sandform2#filtration column is observed by scanning electron microscope(SEM),The resultshows that the surface of mature quartz covered with large amount of manganese oxides andmanganese oxidizing bacteria, manganese oxidizing bacteria adsorbent Mn2+and oxidize it bysecreting extracellular enzymes, then produce an extracellular polymeric morphology, Thismaterial is porous sheet structure,similar to δ-MnO2, beneficial for adsorption of divalentmanganese oxide, nutrition and mass transfer. In addition to biological filter maturationprocess, it is a process of iron and manganese oxidizing bacteria become the dominantbacteria of biological filter microbial system that constitute variety microbes.(3) Mature biological filter of manganese removal that vaccinated autotrophic bacteriahas a certain stability. Single factor experiments showed that manganese biological filter layerare affected by many factors which led to poor effect of manganese removal. Under theexperiment conditions,the maximum filtration rate is12.05m/L, the manganese concentrationin raw water should not exceed3.48mg/L, ammonia concentration is less than3mg/L, organiccarbon in raw water should not exceed5mg/L, Ph value between5.5-8.5,temperature between18-25,intensity control backwash control6.8-8.5(s.m2).Kinetic results show: whenmanganese concentration is high in raw water,Mn2+removal of filter layer belongs tozero-order kinetics, kinetic equation:-dC/dt=0.203, the relation of manganese concentrationand contact time is [Mn2+]=3.189-0.203t,reaction rate constant k=0.203min-1,half life time is3.41min; when manganese concentration is low in raw water, Mn2+removal of filter layerbelongs to first-order kinetics, kinetic equation:-dc/dt=0.14C, the relation of manganese concentration and contact time is[Mn2+]=0.544e-0.14t,reaction rate constant k=0.14min-1,halflife time is4.95min; when manganese concentration is medium in raw water,,Mn2+removalof filter layer belongs between zero-order kinetics and first-order kinetics, kineticequation:-dC/dt=k1C/K3+C. |
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