【作者】 陈晨；

【导师】 马邕文；

【作者基本信息】 华南理工大学 ， 环境工程， 2012， 硕士

【摘要】 工业废水中常含有大量大分子难降解有机物，因此，单一的好氧生化处理工艺不能取得理想的处理效果。厌氧生物技术具有高效降解大分子难降解有机物、低耗产能的特点，在工业废水处理中得到广泛的应用。但传统的厌氧技术中存在以下三个缺点：厌氧微生物生长缓慢，导致厌氧反应器启动缓慢；高浓度难降解污染物水解酸化速率慢，同时丙酸、丁酸等转化为乙酸过程易环境因素影响，在处理过程中易出现酸性末端产物的过度积累，对产甲烷菌抑制作用强烈时，会出现“酸化”现象，导致厌氧体系崩溃；对于含高氮废水，达不到去除氮素的效果，往往需要在厌氧处理工艺后续加设深度处理除氮，导致废水处理流程较长，投资和运营费用大。本文探索解决厌氧处理过程中这三点缺点的具体控制措施，以处理不同C/N废水为研究对象，探索不同进水C/N比时选取择最佳厌氧工艺实现以下目标：避免厌氧反应器“酸化”，以强化厌氧处理效果，在单一厌氧反应器实中实现同时产甲烷反硝化，即同时实现脱碳除氮双重功能，拓展厌氧处理领域。本实验内容包括：寻找快速启动厌氧反应器的方法；探索处理不同进水C/N废水最佳厌氧工艺的选择及机理研究。研究发现低强度超声波能加快启动进程，低强度超声波处理过的颗粒污泥启动IC厌氧反应器历时7天，而对照试验历时10天。低强度的超声波作用提高IC厌氧反应器中COD去除率，具有更高的产气率和最大比产甲烷活性。不同C/N比影响发酵类型的研究中发现：初始进水C/N为12、56、156时，形成丁酸型发酵类型，初始进水C/N200时，即进水C/N较高时，易实现乙醇型发酵，有效避免反应器“酸化”，此时有最高的产甲烷率和出水COD去除率；C/N比为56时胞外聚合物达到最大值，不同C/N比颗粒污泥表面特征也发生变化，对污泥的沉降性有一定的影响。对不同的C/N比培养的厌氧颗粒污泥进行扫描电镜观察，微生物群落表面特征也不相同。进水C/N低时不易实现乙醇型发酵厌氧工艺，但研究发现，进水C/N较低时，同时产甲烷反硝化工艺可以避免反应器内丙酸的积累，有效避免厌氧反应器“酸化”且同时具有脱碳除氮的功能。采用IC厌氧反应器，成熟厌氧颗粒污泥为接种污泥，驯化其具有同时产甲烷反硝化工功能的研究过程中，在进水碳源为葡萄糖，硝酸钠提供硝态氮，COD/NO₃^-为10的条件时，通过进水碳氮负荷不变，逐步减少水力停留时间来驯化厌氧颗粒污泥，历时30天完成厌氧颗粒污泥的驯化，实现了在单一相IC厌氧反应器中同时产甲烷反硝化。实验过程中，25天时达到稳定状态，出水COD去除率达到95%以上，氮的去除率达到96%；稳定时对出水氨氮进行测定，出水氨氮为2mg/L，发现厌氧过程中发生了DNRA过程；对产生的气体组分进行检测，其中甲烷占53%，氮气占47%。COD/NO₃^-为2、4、8、10、16时，出水COD出现先增高后下降的趋势， COD/NO₃^-为2时属于碳源不足，发生反硝化过程，未发产甲烷过程，产气组分未检测出甲烷；COD/NO₃^-为4时COD去除率仅有84%；COD/NO₃^-为8、10、16时， COD去除率较高，分别为89%、95.1%、94.9%。COD/NO₃^-为4、8、10时都有很好的除氮效果，去除率达到了95%左右， COD/NO₃^-为8、10、16时出水检测到了氨氮，发生了DNRA过程。具有同时产甲烷反硝的厌氧颗粒泥对丙酸积累引起的“酸化”有明显的恢复功能。当由丙酸引起的不同酸化程度，依次为基本无“酸化”、轻度“酸化”、中度“酸化”、高度“酸化”时， COD去除率分别达到了91.5%、87.9%、84.89%、81.05%。缓解中度“酸化”时最佳COD/NO₃^-为8。缓解重度“酸化”时最佳COD/NO₃^-为6。更多还原

【Abstract】 Industrial wastewaters always contain abundant refractory organic polymers and highorganic loads, which make that it is hard to achieve the desired treatment effect by singleaerobic biological treatment process. Anaerobic biotechnology is wide used in the treatmentof industrial wastewaters for its effectively degradation ability when treat high concentratedrefractory organic polymers,and low energy consumption. But traditional anaerobictechniques have the following three disadvantages:slow growth of anaerobic microorganismsresulted in the slow speed of start-up of the anaerobic reactor; hydrolysis acidification rate ofthe wastewater which has high concentration of refractory pollutants was slow,the processthat is propionic cid or butyric acid and so on converted to acetate had been affected byenvironmental factors easlly,because of excessive accumulation of ending acidic products inthis process which could take strong inhibition to the methanogens, leaded the anaerobicsystem to collapse; Anaerobic treatment have low nitrogen removal rate when the influentcontain high concentration nitrogen, often need addition of advanced treatment to removenitrogen after anaerobic treatment process,this resulted in longer wastewater treatment process,and much more investment and operating costs. This paper focuses on solves the threedisadvantages of the anaerobic treatment process, deal with different C/N wastewater as aresearch object, explore what is the best anaerobic process when treated different C/N ratioinfluent to achieve the following objectives: to avoid anaerobic reactor acidification and inorder to strengthen the anaerobic treatment effect;also achieve methanogenesis anddenitrification in a single reactor,in order to expand the anaerobic treatment field. Thisresearch mainly includes the following aspects: looking for some ways of quick start-up ofanaerobic reactor; explore the optimal anaerobic process to treat different C/N influent andstudy the mechanism.Low-intensity ultrasound could speed up the start-up process. The start-up of the ICanaerobic reactor by the granular sludge which had been treated by the low-intensityultrasound needed seven days, while the control group needed10days. Low-intensityultrasound increased COD removal efficiency of the IC anaerobic reactor, and made it withhigher gas production rate and the maximum methane-producing activity.There are different fermentation types under different C/N ratio,it found that when initialinfluent C/N ratio were12,56or156, acid-type fermentation can be found, when the initialinfluent C/N was200, ethanol-type fermentation can be found,these type fermentation caneffectively avoid the acidification of thedreactor,and there were the highest methane production rate and the effluent COD removal efficiency under ethanol-type fermentation;when the C/N ratio was56, the extracellular polymeric substances achieved maximum,different C/N ratio leaded characteristics of granular sludge surface to change, there had acertain impact on sludge settleability under different C/N ratio. Observed the culture ofanaerobic granular sludge which were under different C/N ratio from scanning electronmicroscope, found some changes taken place about the surface characteristics of microbialcommunities.Use IC anaerobic reactor and mature anaerobic granular sludge as seed sludge toacclimate sludge coupled with simultaneous methanogcnesis and denitrincation. glucose ascarbon source and sodium nitrate as nitrogen source of influent, COD/NO₃^-ratio was10, theinfluent carbon and nitrogen load were not changed and to gradually reduce the hydraulicretention time to domesticate anaerobic granular sludge, lasted30days to complete thedomestication, to achieved that IC anaerobic reactor coupled with simultaneousmethanogcnesis and denitrincation. In the experiment, the effluent COD removal efficiencywas more than95%,nitrogen removal efficiency was96%after25days; measured stableeffluent,found ammonia nitrogen which concentration was2mg/L, this anaerobic processbe called DNRA process; to detect the gas component, methane accounted for53%, nitrogenaccounted for47%. When COD/NO₃^-was2,4,8,10or16, the effluent COD removel ratioincreased first and then have a downward trend.When COD/NO₃^-was2, carbon source wasnot enough, the denitrification process had occurrenced, but methanogenesis was not befound, gas component was not detected methane; When COD/NO3–was4, COD removalefficiency was only84%; When COD/NO3–was8,10or16, COD removal rates were89%,95.1%,94.9%.When COD/NO3–was4,8or10,there was good removal efficiency ofnitrogen,acchived95%, When COD/NO3–was8,10or16,the enfluent was detected to theammonia nitrogen, this process was called DNRA process.Anaerobic granular sludge with simultaneous denitrification and producing methane hasobviously recovery function on the acidification caused by the propionic acid accumulation.When the acidification degree caused by the propionic acid were basic no acidification, mildacidification, moderate acidification and severe acidification, the COD removal rate of theanaerobic reaction bottle reached91.5%,87.9%,84.89%and81.05%, respectively. Wheneasing moderate and severe acidification, the best COD/NO₃^-values were8and6.更多还原