【作者】 李侃；

【导师】 王晓昌；

【作者基本信息】 西安建筑科技大学 ， 市政工程， 2013， 博士

【摘要】 生物造粒流化床是将混凝造粒固液分离工艺应用于污水处理的一种尝试。通过对装置进水进行预充氧，维持流化床内的好氧状态，使微生物在流化床内得以繁殖与富集，从而实现物化与生化耦合作用下的污染物强化去除。前期针对城市生活污水的实验研究已证明了生物造粒流化床不仅能有效去除污水中悬浮态或胶体态的污染物，而且能去除较高比例的溶解性COD、氨氮和总磷，在总水力停留时间为1~2h的条件下，达到优于强化一级处理的效果。作为一种短流程的一体化污水处理工艺，生物造粒流化床具有良好的推广应用前景。为了揭示生物造粒流化床对溶解性污染物的物化-生化协同作用，本文设计了小型实验装置，采用人工配水，针对生物造粒流化床对溶解性污染物的去除特性、流化床中的颗粒污泥特性、混凝剂对污泥中微生物生理生态的影响开展了实验和理论研究。本文的主要工作及成果如下：（1）生物造粒流化床对溶解性污染物的去除特性在实验室条件下，建立小型生物造粒流化床装置并投入连续运行。生物造粒流化床连续操作控制条件为：PAC50mg/L，PAM3mg/L，上升流速u1mm/s，机械搅拌速度ω25rpm，回流污泥池水力停留时间2h，流化床泥层高度控制范围110cm～130cm；回流污泥池参数的控制为：平均每2个小时回流污泥0.5L至回流污泥池， SS0.82g/L，DO8mg/L。稳定运行条件下对溶解性COD、NH3-N及TP的平均去除率分别为85%、34%和46%。（2）生物造粒流化床对溶解性污染物的去除机理研究流化床对溶解性污染物去除过程中包括混凝、吸附和生物降解等物化和生化作用。量化溶解性COD在不同作用机理下的去除效果为：回流污泥池生化降解46%，混凝去除6%，吸附去除8%，流化床原位生化降解22%，未降解18%；溶解性NH3-N在不同作用机理下的去除效果为：回流污泥池生化降解9%，混凝去除5%，吸附去除10%，流化床原位生化降解11%，未降解65%；溶解性TP在不同作用机理下的去除效果为：回流污泥池生化降解27%，混凝去除1%，吸附去除3%，流化床原位生化降解17%，未降解52%。其中回流污泥池生化降解是完成在回流污泥池中的吸附于回流污泥中溶解性污染物的生化降解作用，因此对于附着于颗粒污泥的溶解性污染物而言，回流污泥池生化降解仍是生物降解的一部分。因此，生物降解对于溶解性COD、NH3-N和TP的总的作用分别为68%、20%和44%，说明生物降解是生物造粒流化床污染物去除的去除效果更为明显。（3）生物造粒流化床中颗粒污泥的物理和生化特性研究生物造粒流化床由下至上不同高度处的颗粒呈现良好的球形状态，颗粒粒径呈沿床高逐渐降低的趋势，其中，10cm、50cm、90cm三个高度的中值粒径d50依次为2.84、2.22、1.92mm。生物造粒流化床中颗粒污泥密度趋于均一，随粒径变化的趋势不明显，有效密度的范围为0.006～0.013g/cm3，远高于常规絮凝体的有效密度，说明通过生物造粒流化床操作形成的颗粒污泥具有更加紧实的构造。对流化床中的颗粒污泥进行生化特性分析可知，DO进入流化床内不断被消耗，从入口处的8mg/L降至顶部的1.7mg/L，且主要在底部被消耗。同时沿流化床自下而上MLSS逐渐降低，但每个断面MLSS的浓度远高于常规活性污泥法。细菌计数结果表明，流化床柱体内各断面生物量均在108的数量级，与常规活性污泥法的生物量基本相当，由于流化床底部营养基质丰富，DO充足，因此微生物量最高。随着流化床高度的增加，生物量呈降低的趋势。（4）生物造粒流化床中颗粒污泥中的微生物群落分布特性运用FISH技术对流化床中颗粒污泥的亚硝化菌和硝化菌鉴定分析得出，在流化床10cm、50cm、90cm处AOB/DAPI和NOB/DAPI分别达到3.4%，3.9%，2.5%以及1.8%，1.8%。1.4%。表明就亚硝化菌和硝化菌的分布而言，在流化床高度上没有较大变化的。在生物造粒流化床形成的颗粒污泥中AOB、NOB占DAPI染色总菌的比例与悬浮活性污泥法中的比例基本相同；而每个高度的颗粒污泥中NOB的数量均低于AOB的数量，这可能是由于NOB具有较低的比增值速率的缘故。从DGGE谱图可以看出，生物造粒流化床内微生物种群丰富，且因其独特的空间结构使好氧、兼性、厌氧微生物均能生长。生物造粒流化床处理工艺装置不同位置的活性污泥中微生物的结构相差不大，曝气池与流化床内微生物种群结构对比，少数细菌的种类与数量在曝气池中锐减(如兼性厌氧细菌Actinobacillus)，但总体来说相差不大，其余优势种群都是好养菌群（Actinobacillus，Arcobacter sp.，Epsilon proteobacteria和Beta proteobacteria类群）。表明在微生物对于底物变化和DO浓度改变适应性较好，工艺运行较为稳定。为了提高生物造粒流化床的脱氮能力，针对生物造粒流化床颗粒污泥进行3个月的亚硝化细菌和硝化细菌的富集培养，运用PCR-DGGE技术鉴定出富集培养液中完全自养型硝化菌的优势菌群为Nitrosospira sp.（亚硝化螺菌）和Nitrobactersp.（硝化杆菌），且还被鉴定出异养细菌Pseudomonas sp.（假单胞菌）以及Pseudomonas aeruginosa（铜绿假单胞菌）。这些异养细菌Pseudomonas sp.为好氧反硝化菌，与自养硝化细菌起到了共生的作用。（5）混凝剂对颗粒污泥中功能菌群的影响研究在生物造粒流化床的操作条件基础上，利用SBR反应器进行了不投加和分别投加聚合氯化铝（PAC）和聚丙烯酰胺（PAM），对活性污泥生长及其污染物降解特性的对比试验。生物量分析和FISH检测结果表明投加PAC和投加PAM不会影响活性污泥中微生物的繁殖和生长。对污染物的去除效果分析发现，投加PAC和投加PAM的反应器都要比未投加药剂的反应器COD的去除率要高；三种反应器内各种形态的氮去除效果非常接近，说明PAC和PAM对微生物的硝化作用无抑制作用；且化学除磷能够提高磷的去除率。（6）生物造粒流化床颗粒污泥的动态稳定性研究利用基于两个生物造粒流化床的二级串联交替运行模式研究了流化床颗粒污泥的动态稳定性。生物造粒流化床采用二级串联交替运行模式后，总的水力停留时间延长，有效处理泥床高度加倍，溶解性污染物的去除得到强化，溶解性COD、氨氮、磷在二级柱的去除率分别为10%、3%以及5%。在交替轮回的一个周期内，由于铝盐混凝剂和高分子絮凝剂投量减小，颗粒的粒径减小，反之，颗粒粒径增大。在流化床多次轮回切换，颗粒污泥多次经历“破碎——成长——再破碎——再成长”的过程中，颗粒的有效密度并未发生明显变化，且此条件下形成的颗粒污泥仍保持着紧实的结构。流化床中的颗粒能保持良好的动态稳定性。更多还原

【Abstract】 It was a new technology in wastewater treatment that fluidized-pellet-bedbioreactor(FPB) which could integrate the sludge granulation and pellet solid/liquidseparation in one reactor. By providing appropriate biological environment such asoxygen, the microbe were enrichment, and then the contaminants could be removedeffectively on the physical-biochemical effects. On the earlier research, it was provedthat the FPB could not remove particular or colloidal contaminants efficiently, but alsocould remove high percentage of soluble COD, nitrogen and phosphorus. And on thecondition of HRT1-2h, the removal of contaminants in FPB was more effective thanCEPT. As one type of short-process treatment, the prospect of popularization andapplication of FPB ischeerful. In order to reveal synergic physical-biochemical effectsof soluble contaminants, a small-scale FPB system with simulated wastewater wasestablished, on the research of the removal of soluble contaminants, physical andbiochemical property of pellets, and influence of coagulant on microbe in FPB. Resultsand findings in the study were including the perspectives as:(1) Removal of soluble contaminants in FPBOn the condition of laboratory, a small-scale FPB system was established and along-term operation was carried out. The operational conditions in FPB weredetermined as: PAC dosage50mg/L, PAM dosage3mg/L, upflow velocity1mm/s,mechanical stirring speed ω25rpm, HRT in aerated tank2h, and the blanketheight110cm～130cm; the parameters in aerated tank were determined as: SS0.82g/L,DO8mg/L and recycled0.5L sludge to aerated tank in every2hours. Under the aboveconditions, the removal efficiency for soluble COD, nitrogen and total phosphorus was85%,34%and46%. The removal of soluble contaminants was including coagulation, adsorption andbiodegradation. The removal of soluble COD in different mechanisms was estimated aspreaeration46%,coagulation6%, adsorption8%, biodegradation22%, undegradematerial22%; the removal of soluble nitrogen in different mechanisms was evaluated aspreaeration9%,coagulation5%, adsorption10%, biodegradation11%, undegradematerial65%; the removal of soluble phosphorus in different mechanisms was estimated aspreaeration27%,coagulation1%, adsorption3%, biodegradation17%, undegradematerial52%. The preaeration fulfilled in the aerated tank was the biodegradation of solublecontaminants which were adsorbed in the recycle sludge. For soluble contaminantsadsorbed in the pellets, it was equivalent to extending aeration which was also the partof bio-degradation. Therefore, the removal of soluble COD, nitrogen and phosphoruswith biodegradation was68%,20%and44%, suggesting that biodegradation couldremove soluble contaminants effectively.(2) Physical and biochemical property of pellets in FPBThe formation process of pellets, the morphological characteristics and sizedistribution of the pellets in the reactor were examined, and the following results couldbe obtained: the pellets in the reactor were sphere and their sized decreased along theheight of reactor, namely, the average sizes of pellets which were described as d50fromthe bottom, middle and upper of the reactor were2.84,2.22,1.92mm. It was found thatthe effective density of pellets slightly decreased with the increasing diameter. Theeffective density was in the range of0.006-0.013g/cm3, which was much higher than theactivated sludge and was showing the compact structure.As the analysis of the biochemical property of pellets, DO was continuouslyconsumed from8mg/L in the bottom to1.7mg/L on the top of the reactor, obviously,mainly consumed in the bottom. The MLSS in the reactor decreased along the height ofreactor which was much higher than the activated sludge. It was found that the biomassin the reactor was in the magnitude of108, which was close to the activated sludge. Thebiomass in the bottom of the reactor was highest as a result of the plenty of substrateand sufficient DO, and the biomass in the reactor decreased along the height of reactor.(3) Microbial community distribution in the pellets of FPBAs the identification of nitrosobacteria and nitrobactor using FISH, it could be judged that the percentages of AOB/DAPI and NOB/DAPI from10cm,50cm,90cm inthe reactor were3.4%,3.9%,2.5%and1.8%,1.8%,1.4%respectively. There wasslightly changed along the height of reactor in the distribution of nitrosobacteria andnitrobactor. The percentages of AOB/DAPI and NOB/DAPI in the pellets of FPB wereclose to the activated sludge.It was shown from DGGE profile that the bacteria in FPB are abundant. Thebacteria structure in different position of FPB were slightly changed, and the amount ofbacteria such as Actinobacillus declined sharply in the aerated tank, but the anotherbacteria were stable which were Actinobacillus, Arcobacter sp., Epsilon proteobacteriaand Beta proteobacteri. It was revealed that the bacteria could be adapted to thevariation of contaminants and DO, and the operation of FPB could be stable.AOB and NOB from FPB pellets were purified in3months in order to improve thenitrogen removal. It was found that Nitrosospira sp., nitrobacter sp., pseudomonas sp.and pseudomonas aeruginosa could be identified from the enriched solution usingPCR-DGGE. Pseudomonas sp. could be revealed that was co-existence with NOB,which was denitrifying bacteria.(4) Influence of coagulant on microbe in FPBIt was found that the influence of the coagulant was dominated in FPB on thebacterial community of sludge by comparing a set of SBR reactors with the samecondition of PAC and PAM addition. It was indicated that the addition of PAC and PAMcould not have obvious influence on nitrifying bacteria by means of biomass analysisand FISH technology. The removal efficiency of TP was increased significantly withPAC addition, and COD removal was improved with the addition of PAC and PAM.Howerver, there was no obvious improvement of nitrogen removal in the same reactors.(5) Stabilization of FPB with two alternate stagesIt was revealed that the mechanism of soluble contaminants removal and thestabilization of pellets in FPB with two alternate stages. The size of pellets decreaseddue to the lessening PAC and PAM; on the converse, the sizes of pellets were increased.After two stages alternating repeatedly, it was shown that the pellets got into the cycleof“broken-grown-broken-grown”, and the effective density of the pellets did not changeobviously, indicating the pellets possessed a dense structure on this operation. It was revealed from the experimental that the pellets had very good dynamic stability. Due tothe FPB with two stages and extending HRT, the removal efficiency of solublecontaminants could be enhanced.更多还原