【作者】 张勇；

【导师】 吕锡武； 张林生；

【作者基本信息】 东南大学 ， 环境工程， 2006， 博士

【副题名】反应器降解性能、机理及应用

【摘要】 好氧生物处理是污水处理最基本最常用的方法。常规好氧生物处理工艺普遍存在曝气能耗高、负荷低、占地大等缺点,尤其对高浓度、难降解有机废水处理效率低,制约了其在工业废水处理领域的应用。此外,常规好氧生物处理工艺剩余污泥产量及后续污泥处置费用高,总体运行费用居高不下。本论文对好氧处理新工艺——压力式接触氧化反应器进行了系统研究,并结合实际研究了厌氧(释磷)-压力接触氧化法脱氮除磷工艺、农药废水厌氧水解-压力式接触氧化工艺等组合工艺的处理效果,完成了以下主要研究工作:对压力式接触氧化法运行性能及处理效果进行了全面研究。与常规接触氧化法相比,射流曝气-压力式接触氧化法采用加压方式辅以自吸式射流器作为供氧装置,供氧性能有根本改善,气水比显著减少,射流曝气对水中脱落生物膜及游离微生物的剪切作用可显著提高其生物活性,压力式接触氧化工艺处理模拟废水,最佳HRT为1.0h左右,当NV不超过15 kgCOD/(m3·d),气水比仅需1~4,DO可保持4~5mg/L,COD平均去除率在80~95%,出水COD低于100mg/L。研究了压力式接触氧化法微生物的耐盐性及抗压性。压力式接触氧化法在未经驯化的情况下,当进水盐浓度达20g/L时,处理效果依然在正常范围内,与常规活性污泥法及生物膜法相比,压力条件下反应器中的微生物能够承受高盐度冲击。在压力条件下经一定时间的驯化适盐菌可以生存,保证了压力式接触氧化法对高盐度有机废水的处理效果;低压范围内(0.1~0.4MPa)压力对微生物代谢无明显不利影响,相同溶解氧浓度下压力的增加对生物膜耗氧速率及COD去除率无明显影响,相同容积负荷下的耗氧速率主要取决于反应器内的溶解氧浓度,DO越高、耗氧越快。压力式接触氧化法的运行特征使其综合了能量解耦联(富底物条件、高浓度溶解氧环境)和隐性生长(载体挂膜、缺氧层的存在)两方面的污泥减量化机理,是有效的污泥减量技术;在容积负荷为16.8 kgCOD/(m3·d)范围内的污泥产率为0.07~0.14kgSS/kgCOD,与常规工艺相比具有明显的污泥减量优势。压力式接触氧化法具有明显的同步硝化反硝化作用。当HRT=1.8h,DO低于5.4mg/L时可获得90%以上的反硝化率,反硝化进行得较为彻底,氨氮硝化效果的好坏直接影响整体脱氮效率,最佳硝化反应出现在容积负荷10~12kgCOD/(m3·d)范围内,NH4+-N去除率达80%左右,TN去除率达70~80%。针对压力式接触氧化法的生物膜特征、有机物去除效果、脱氮效果等方面不同于常规接触氧化法的特点,从耗氧速率与总生物量、氧利用率、SBCOD的降解及同步硝化反硝化脱氮四个方面加以论证并提出缺氧水解-好氧代谢的有机物去除机理,同时从旋转球形悬浮填料球形生物膜内的多孔丸传质模型及有机物降解动力学两方面作进一步验证。分析了压力式接触氧化反应器内CO2的溶解过程及曝气吹脱过程,结合进、出水pH关联试验,提出压力反应器内的酸碱缓冲机制,当进水为中性或弱酸性时为CO2溶解-pH值下降-水中游离CO2浓度增加-曝气吹脱-pH值上升;当进水为碱性时为pH值上升-CO2溶解-中和-pH下降。缓冲体系的存在使反应器可承受较高的酸碱冲击负荷,使该工艺在工业废水处理领域的应用范围更加广泛。更多还原

【Abstract】 The conventional aerobic wastewater treatment technology is a fundamental and constantly used technology. At the same time, several disadvantages exist in the technique, such as high aeration energy consumption, high land occupancy and low volume load. Moreover, high sludge yield and large sludge disposition expense bring on a great operation payout. The pressurized biological contact oxidation reactor as a new aerobic wastewater treatment technology was comprehensively studied. Several combined technologies based on actual wastewater and treating needs were also researched, concluding simultaneous nitrogen and phosphorus removal of anaerobic phosphorus release-pressurized biological contact oxidation process, pesticide wastewater treatment by hydrolysis acidification- pressurized biological contact oxidation process. The following results were obtained:The operating capability and treating effect of pressurized biological contact oxidation process were generally studied. Compared with conventional biological contact oxidation process, as the jet aeration-pressurized biological contact oxidation process adopted pressure and self-priming jet aerator as aeration devices, the aeration capability was remarkably advanced, and the air-water ratio reduced obviously. Jet aeration can enhance the activity of dissociative microorganism effectively. The best hydraulic residence time(HRT) of domestic sewage treated by pressurized biological contact oxidation process was about 1.0 hour. When the volume load was less than 15 kgCOD/(m3·d), the dissolved oxygen(DO) could maintained in 4~5mg/L while the air-water ratio was only 1~4. The technology could get a high COD removal ratio as 80~95%, and COD of the treated water could keep lower than 100mg/L.The salt and pressure resistant ability of microbe in pressurized biological contact oxidation reactor was studied. The studies showed that even the biofilm was not domesticated and the salt concentration of the wastewater was as high as 20g/L, The microorganism in pressurized reactor could endure a higher salt concentration impact than which in a conventional activated sludge or biofilm process. Salt-tolerant microorganism could exist in pressurized condition after a period of domestication, which ensured the effect of organic wastewater with high salt concentration treatment by pressurized biological contact oxidation process. Low pressure (0.1~0.4MPa) had little impact on microorganism metabolism, and higher pressure made no difference to oxygen uptake rate of biofilm and COD removal ratio. The oxygen uptake rate under the same volume load lied only on the dissolved oxygen concentration.Two aspects of excess sludge reduction mechanism was included in pressurized biological contact oxidation process, including uncoupling metabolism (substrate-sufficient conditions and high concentration of dissolved oxygen) and cryptic growth (biofilm and presence of anoxic layer). The pressurized bio-contact oxidation process was an effective excess sludge reduction technology. The sludge yield was about 0.07~0.14 kgSS/kgCOD when the volume load changed within 16.8 kgCOD/(m3·d), which showed that the technology had a remarkable superiority of excess sludge reduction compared with conventional technologies.更多还原