| Most study about aerobic granule has been based on the sequencing batchreactor (SBR) and the applicaiton of aerobic granulations were then developed in theSBR. However, little work has been done on cultivate aerobic granules in acontinuous-flow bioreactor with simple structure realistic for engineering. Theconfiguration of CAFB was the simplest continuous-flow aerobic granular bioreactorreported by now. But, the running stability of the reactor has been a key issue torestrict its development. In this study，the aerobic granular was cultivated in theCAFB, and the effect of vaccination with biofilm sludge to sludge granulation andrunning stability was investigated. While, the effect of particle size on heavy metaladsorption characteristics was also studied by adsorption experiment of Ni2+usingdifferent particle aerobic granular sludge. This study would provide a theoretical basisand reference for the stabilization of aerobic granule cultivation and its application.Reducing the aerobic granulation period and stabilization the aerobic granulesystem was strongly expected. In this work, enhanced aerobic granulation wasachieved in the CAFB with backwashed bioiflms as seed and municipal wastewater assubstrates. The start-up period of this bio-system was as short as25days, which wasmuch shorter than that with activated sludge as inoculation. In the stable stage, theCOD removal efifciencies and nitrification efifciencies could reach90%and60%around respectively. Moreover, the operation continued for totally90days，which wasmuch more stabilized than the previous reports with activated sludge as inoculation. Itseemed biolfims promoted the granulation and the granules stabilization apparently,as the formed granules are a kind of special bifilm. Microbial distribution analyzedwith the florescence in situ hybridization (FISH) technology showed thatnitrite-oxidizing bacteria (NOB) and ammonium-oxidizing bacteira (AOB) wereenriched in the entire granules. The substrate and dissolved oxygen diiffision profilesin the granule evaluated by mathematic models revealed that the complete mixingregime took the responsibility of the distinguished microbial population: low level ofCOD and the abundance of dissolved oxygen in the entire granule promoted the growth of AOB and NOB in the deeper layer and improved nitriifcation performance.At present，a major part of investigations about heavy metal adsorption withaerobic granular sludge focus on particles in mature stage, particle diameter of whichis around1mm. There are rare studies reported on granular sludge of different range.This experiment was based on continuous CAFB reactor and four kinds of granularsludge and lfoes (>800pm,500-800jxm<，200-500jam，200jam) obtained served asadsorbate. Combined with FTIR，XRD，XPS and so on，it is found that physicaladsorption, electrostatic adsorption, ion exchange and surface complexation occuredobviously while inorganic micro precipitation play a weak role. Aerobic granularsludge of diameter from200-500^im showed best adsorption saturated amount toNi2+. By comparison, granular sludge with more than200|am mainly exertedadsorption effect while floes less than200|am possessed lower adsorption capacitydue to limitation by electrostatic adsorption, ion exchange and surface complexation.Granular sludge more than800jam not only have lower capacity of adsorption butenjoy weak ion exchange ability due to specific area and porosity. Influenced byprotein distribution，surface complexation also decreased. Results of FTIR showedprotein was the dominant material in complexation. Analyses of XPS-Ni，XPS-C，XPS-O, XPS-N further conifrmed it and the particularity of granular sludge more than800(im. |
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