Experimental Study On Manganese Removal Using Bacteria Immobilization Technology

In this thesis, a strain of highly effective iron and manganese removal bacteriawhich isolated from mature bio-filterwas offered as target bacteria for imobilization.Sodium alginate (SA) and diatomite are chosen as the encapsulating carrier. Embedment immobilized methodswas used to prepare immobilized bacteria.Immobilizedmicroorganismwas prepared by the embedding method; then the preparedmicrospheres were crosslinked with ethylenediamine and harded with glutaraldehyde;finally the modified fixed dispel manganese bacterium microspheres were prepared.The modified manganese removal bacteria microspheres were experimented by analogfilter column of biological manganese removal.Embedding condition was analyzed by single factor experiment and the bestcondition of the embeddingwas that SA concentrationwas1.5%, the content ofdiatomitewas1g/100ml, package bacteria amount was15%, CaCl2concentrationwas3%, calcification time4hours, ethylenediamine concentration was0.3mol/L,crosslinking time of1h, glutaraldehyde concentrationwas0.3mol/L, and hardeningtime was5minutes. Immobilized microorganism which formed through selection andcultivation were analysed by scanning electron microscope(SEM), and the resultsshowed that the biological microsphere surface had density of the spherical shell, andits internalwas the three-dimensional grid structure. The surface of density ofspherical shell can effectively prevent the outflow of bacteria in microsphere andinternal grid structure benefits microbial adhesion and reproduction. So this structureincreased the mechanical strength of immobilized microspheres, at the same time itmade for transmission of the substrate, metabolites and dissolved oxygen.Under the condition of different empty bed contact times (EBCT), the start-upperiod of filter columnwas not the same. When manganese concentration of the inflowwas0.9~1.2mg/L and EBCTwas30minutes, manganese concentration of theeffluent after running reasonably maintain below0.1mg/L. If the EBCT was graduallyshorten, manganese concentration of the effluent appear small fluctuations; but after aperiod of adaptation, the removal rate of manganese reach over90%again.