【作者】 张斯；

【导师】 马放；

【作者基本信息】 哈尔滨工业大学 ， 环境科学与工程， 2012， 博士

【摘要】 生物强化技术对改善废水处理系统的出水水质及提高运行的稳定性具有重要的作用，也是废水处理领域的热门研究方向之一。该技术以生物载体为依托，在保持功能菌数量和活性的基础上，强化功能菌对目标污染物的去除作用。因此，开发相容性好、不改变现有处理系统工艺的生物载体，以期最大限度地发挥生物强化技术的效能是十分必要的。特别是利用生物质材料如稻草、竹丝等为生物载体，成为目前的热点。基于此，本研究致力于菌丝球的研发，将其作为一种新型的生物载体用于难降解污染物的去除。以黑曲霉Y3形成的菌丝球为对象，研究了载体菌丝球的制备条件和生长、结构等特性。结果表明，蔗糖和氯化铵是菌丝球生长的最适碳源和氮源，最佳量分别为10g/L和1g/L。环境因子中温度和剪切力对菌丝球制备过程影响显著，在一定范围内升高温度有利于菌丝球生物量的增加，160r/min形成的剪切力条件下菌丝球生物量达到最大，约为5.25g/L培养基。菌丝球生长迅速（从孢子接种到菌丝球成熟只需要72h），沉降性能良好（球径3mm的菌丝球沉速约为0.01m/s），其属于大孔隙结构载体、表面带正电荷、菌丝表面附有以糖和蛋白为主的胞外聚合物。通过吸附实验证明，菌丝球对细菌具有良好的吸附性能，吸附量达7.7×10¹⁰cfu/g菌丝干重，且可以将菌丝球或固定特定功能菌的混合菌丝球冷冻干燥保存。菌丝球大孔隙结构的特点，造成其应用过程中存在结构稳定性差、易破损的问题。为此，通过投加生物絮凝剂的方法，提高菌丝球的结构稳定性。研究发现，培养菌丝球的同时添加生物絮凝剂，可以不改变菌丝球的内部结构，其完整率由75.1%提高到83.6%，干重由0.0677g/100mL提高到0.0767g/100mL。另外，改变反应器的结构，实现定向导流，避免混乱剪切力对菌丝球造成的破坏，也可以提高菌丝球结构的稳定性，延长其使用寿命。采用序批式反应器（SBR），考察了菌丝球作为生物质载体固定苯胺降解菌，对目标污染物的降解效能。结果显示，系统运行7周期后，对苯胺的去除稳定，达到0.9mg/（mg生物量·d），而活性污泥系统的去除量仅有0.6mg/（mg生物量·d），证明菌丝球作为生物质载体是可行的，能够有效地实现工程菌群的固定化、维持系统菌群结构的稳定性和对目标污染物的高效降解。为了进一步提高功能菌的活性，在系统中添加电气石，反应系统的启动时间从7个周期缩短到1个周期，系统启动加速，且系统的运行更加稳定。运用生态位分离理论和微生物协同代谢的原则，实现载体菌丝球固定菌群的多样性和功能性，将多种功能菌群固定在菌丝球上，并投加到序批式气升反应器（SBAR）系统中。系统运行结果表明，逐步提高进水苯胺浓度，系统出水指标稳定，对冲击负荷有较强的抵抗能力，苯胺降解和硝化反硝化过程顺利进行，氮的去除率达到80%左右，解决了苯胺废水处理出水氨氮浓度过高的问题。群落组成分析表明，菌群主要由变形细菌门（Proteobacteria）和放线菌门（Actinobacteria）组成，菌群组成稳定、多样性丰富，固定的功能菌能稳定存在。为了验证菌丝球作为生物质载体对底物适应的广谱性，选择菌丝球固定苯酚降解菌，探讨此类废水的处理效能。研究结果表明，苯酚降解菌在系统中稳定存在，运行5个周期后，系统对酚类化合物和TOC的净化效果稳定，对总酚的去除效能达到0.5mg/（mg生物量·d），高于对照活性污泥系统的0.4mg/（mg生物量·d）。系统群落菌群主要由变形细菌门（Proteobacteria）、放线菌门（Actinobacteria）和杆菌门（Bacteroidetes）组成，菌群组成稳定、多样性丰富，证明菌丝球作为生物质载体，能够有效地实现工程菌群的固定化、维持系统菌群结构的稳定和实现对目标污染物的降解。更多还原

【Abstract】 Bioaugmentation was one of popular directions in wastewater treatmentresearches and played an important role in the field of improving water quality andsystem operational stability. The technology enhanced the removal efficiency totarget pollutants relied on biological carrier to maintain the concentration andactivity of functional bacteria. Therefore, the development of biological carrierswith compatibility and without changing the treatment process was necessary tomaximize the effectiveness of bioaugmentation technology. Biomass materials suchas straw, bamboo and others had been the research focus as biological carriersrecently. Based on this, the study was to develop mycelial pellet as a new biomasscarrier in bioaugmentation, and mycelial pellet as a carrier immobilized functionalbacteria was used to remove recalcitrant pollutants.The preparation conditions and characterizations of growth and structure werestudied with Aspergillus Y3. The results showed that sucrose and ammoniumchloride were the best carbon and nitrogen sources for the growth of mycelial pellet,and the best concentrations were10g/L and1g/L, respectively. Temperature andshear force influenced the preparation process of mycelial pellet significantly. Thebiomass of mycelia increased by the temperature rose within a certain range, and themaximum biomass of mycelia about5.25g/L was gained under the shear force of160r/min rotation speed. Mycelial pellet grew rapidly (72h was used from sporesinoculated to mycelial pellet maturation), and had good settlement performance(Settling velocity of mycelial pellet with3mm diameter was about0.01m/s).Mycelial pellet had a good adsorption to bacteria (7.7×1010cfu/g dry weightmycelia) because of its large pore structure, positive surface charged, adhesioncoursed by extracellular polymeric substances. And mycelial pellet or combinedpellet with functional bacteria could be freeze-dried.There was a poor structural stability in application process of mycelial pellet asa biomass carrier because its large pore structure characteristic. Therefore,structural stability of mycelial pellet was enhanced by adding bio-flocculant. It wasfound that the integrity rate of mycelial pellet was raised from75.1%to83.6%and the dry weight from0.0677g/100mL to0.0767g/100mL by adding bio-flocculantwithout changing the internal structure. In addition, directional shear stress tomycelial pellet obtained by improving reactor hydraulics conditions so that thedamage caused by confusion stress could be avoided. It was also an effective meanto improve the structural stability extend service life of mycelial pellet.The feasibility of target pollutants removal by mycelial pellet as a biomasscarrier was studied in sequencing batch reactors (SBR). The results showed thatpurification of aniline was stable after7cycles running of the system, and theremoval efficiency of aniline was0.9mg/(mg biomass·d), significantly higher thanthe control system with activated sludge,0.6mg/(mg biomass·d). It was proved thatmycelial pellets as biomass carrier is feasible. The effectively immobilized offunctional bacteria, stability maintaining of bacterial structure in system, and targetpollutants degradation were achieved. Tourmaline was used to improve thedegradation ability and adaptability of combined mycelial pellet, and reduced thestart-up time of SBR system from7cycles to only1cycle with more stability.Diversity and functional of bacteria immobilized on mycelial pellet wererealized based on the theory of niche separation and principle of microbialco-metabolism. And the combined mycelial pellet was used in sequencing batchair-lift reactor (SBAR) system. The results showed that the effluent indicators of thesystem were stable and had a strong resistance to the impact load with graduallyincreasing of influent aniline concentration. Aniline degradation andnitrification-denitrification processes were well conducted, with nitrogen removalrate about80%solving the problem that ammonia concentration was high ineffluent of aniline wastewater treatment system. The bacterial structure in systemwas stable and rich in diversity, and was mainly formed by Proteobacteria andActinobacteria, including the bacteria enhanced.Mycelial pellet immobilized phenol-degrading bacteria was selected to degradewastewater contained phenolic compounds in SBR as a supplement experiment toverify it had common adaptability to substrates as a biomass carrier. The resultsshowed that phenol-degrading bacteria grew and worked continuously in system.Phenolic compounds and TOC were removed stable after5cycles running, withtotal phenol removal efficiency of0.5mg/(mg biomass·d), significantly higher thanthe control activated sludge system0.4mg/(mg biomass·d). The bacterial structure in system was stable and rich in diversity, and was mainly formed by Proteobacteria,Actinobacteria and Bacteroidetes. Immobilization of function bacteria, maintainingthe bacteria structure and system stability, and degradation of target pollutants wereachieved by mycelial pellet as a biomass carrier.更多还原