【作者】 於建明；

【导师】 陈建孟；

【作者基本信息】 浙江工业大学 ， 环境工程， 2013， 博士

【摘要】 大气污染已成为越来越突出的环境问题。除NOx、SO2污染治理继续得到重视外,对石化、制药等工业生产过程中排放的挥发性有机污染物(VOCs)进行有效控制是改善大气环境质量的重要途径之一。与传统的物理、化学等处理技术相比,生物净化技术具有建造和运行成本低、无二次污染等优点,特别适合于治理大气量、中低浓度、生物降解性好的VOCs废气；但对于所含目标污染物水溶性和生物降解性差的VOCs,运用单一生物净化技术净化效果并不理想。本论文将真空紫外(VUV)光解作为生物降解的协同强化技术净化废气中的二氯甲烷(DCM),重点研究VUV光解含DCM废气的影响因素、光解产物形态、光解动力学,明晰光解反应最适条件及作用机理；研究生物净化DCM技术,优化生物降解工艺参数,阐明生物降解途径与机理；研究VUV-生物耦合技术协同净化DCM废气的具体效果与参数优化,掌握两者的协同强化机理。本论文系统研究了停留时间EBRT、进气浓度、反应介质等对DCM光解效率的影响,并在分析主要光解产物基础上推断出光降解机理；建立光解数学模型,定量描述进口浓度、出口浓度与停留时间之间的关系。VUV光解DCM主要通过直接光解、羟基自由基(OH·)和臭氧氧化,主要产物是甲醛、甲酸、乙酸、乙醛酸等小分子醛酮类、羧酸类物质,水溶性大幅提高；BOD/COD测试结果表明光解产物可生化性有明显改善,为提高生物净化效率提供了可能。从杭州四堡污水处理厂的厌养池中筛选到1株DCM降解菌：Pandoraea sp. LX-1(Genebank NO:JN021530,保藏号为CCTCC M2011242),通过响应面法获得其最佳培养条件为：培养温度32℃,培养基的pH和盐度分别为7.28和0.66%。建立了生物滴滤塔(BTF,聚氨酯小球填料)和生物过滤塔(BF,营养缓释型填料),分别对DCM进行净化处理。采用气液逆流操作进行挂膜,BTF和BF分别在25d和22d后挂膜完成。稳定运行的实验表明：BTF和BF对DCM的最大去除负荷分别为23.2g·m-3·h-1和33.46g·m-3·h-1。分别建立BTF和VUV-BTF装置,利用构建的复合菌群进行挂膜,两系统完成挂膜时间分别为21d和18d。稳定运行阶段实验结果表明,当DCM进气浓度为400-600mg·m-3,相对湿度为75-80%,相同停留时间下,VUV-BTF协同工艺对DCM废气去除率RE较BTF系统高出14～22%,协同工艺和单一系统的最大矿化率分别为81.56%、73.16%；在协同工艺中,VUV段主要承担DCM污染负荷的转化,BTF段则主要承担污染物的矿化,紫外光解强化了中间产物在BTF内的传质过程和可生化性,其去除能力高于VUV与BTF单元去除能力之和；通过EPS等分析表明,协同工艺中BTF单元生物膜比单一BTF系统生物膜的活性更好、厚度更适宜、微生物菌群结构更多样、常量元素需要量更多。工程试验分析表明,UV-BTF联合技术更能适应非稳态的实际工况,具有良好的环境和经济效益。更多还原

【Abstract】 Air pollution has become an increasingly prominent environmental problem. While treatments of NOx and SO2pollution continue to receive adequate attention, effective control of volatile organic compounds (VOCs) emitted from petrochemical, pharmaceutical and other industrial processes is one of the important ways to improve atmospheric environment, As a competitive alternative to traditional technologies such as physical and chemical processes, biopurification technology has many advantages such as lower costs and less secondary pollution. Thus, it has been widely used in treatment of large flow, low and medium concentration, and easy biodegradable VOCs.However, the single biopurification process is not efficient for treatment of insoluble and less biodegradable compounds.In this paper, the vacuum ultraviolet (VUV) technology was used as a synergistic and reinforced pretreatment for biodegradation of dichloromethane (DCM), research on the influence factors, intermediates and kinetic analysis was conducted with the optimal conditions and degradation mechanism determined, DCM biopurification was studied with process parameters optimized and its pathway and mechanism expounded, effect of the integrated VUV and biopurification technology on efficient synergistic DCM purification as well as optimization of parameters was investigated with the synergistic and reinforcement mechanism discovered.In this research, effects of factors including EBRT, inlet concentration, reaction media etc. on DCM photodegradation were studied systematically, a photodegradation pathway was proposed by analysis of the identified intermediates, kinetic models were established to quantitatively describe the mutual relationship between inlet concentration, outlet concentration and EBRT. DCM photodegradation was achieved by the combined roles of photolysis, OH·and O3photooxidation, and the main intermediates were micromolecular aldehydes and ketones, and carboxylic acids such as formaldehyde,formic acid,acetic acid, and glyoxylic acid etc.,with greatly enhanced solubility. BOD/COD test results showed that the biodegradability of photodegradation intermediates was significantly improved, providing a basis and possibility for enhanced biodegradation efficiency.One DCM bacteria capable of degrading DCM, Pandoraea sp. LX-1(Genebank NO:JN021530, Collection No:CCTCC M2011242) was selected from the aeration tank of Hangzhou Sibao Wasterwater Treatment Plant, with the optimal culture conditions of temperature32℃, Culture medium concentration and salinity7.28and0.66%respectively. BTF and BF packed respectively with either-based polyurethane foam and nutrition slow release fillings were built for purification of DCM。The start-up of BF and BTF was finished by gas-liquid phase joint reverse inoculation within25d and22d, respectively. Stable operational experiments showed that the maximum removal load of DCM by BF and BTF were respectively23.2g·m-3·h-1and33.46g·m-3·h-1.BTF and VUV-BTF were built, and their startup was finished with21d and18d, respectively Stable operational experiments showed that with DCM inlet concentration of400-600mg·m-3, relative humidity of75～80%and the same EBRT DCM, removal efficiency by the integrated VUV-BTF system was14～22%higher than that by the single BTF system, with their maximum mineralization rate of81.56%、73.16%, respectively. In the integrated system, the transformation of DCM pollution load was mainly conducted by the VUV section while the mineralization was mainly undertaken by the BTF section. The mass and biodegradability in BTF were intensified by photodegradation, thus a synergistic purification of higher concentration DCM was made possible in the integrated system, with its removal capability higher than the combined removal capability of the single VUV and BTF processes. EPS analysis showed that the integrated UV-BTF system had a better biofilm activity than BTF, more use of trace elements, more optimal biofilm thickness and more diversified biomass population. Engineering application analysis indicated that the integrated UV-BTF technology had greater adaptability to unstable application conditions and thus better environmental and economic prospects.更多还原