【作者】 秦统福；

【导师】 沈本贤；

【作者基本信息】 华东理工大学 ， 化学工艺， 2011， 博士

【摘要】 努力研发炼油污水先进的生物降解技术,提高炼油废水净化和循环利用水平是节约水资源、实践绿色理念的需要。本文采用气升式内循环气液固三相流化床反应器,结合UBD菌固定化包埋技术,对炼油污水进行连续动态生物降解。中石化上海高桥分公司炼油污水经高效降解后,COD从624 mg/L降至93.6 mg/L,去除率85.0%,石油类含量从48.7mg/L降至2.4mg/L,去除率为95.1%,出水水质达到中华人民共和国污水综合排放一级排放标准(GB8978-1996)。首先通过间歇试验考察了UBD菌对污水的适应性,得出此菌不适宜降解含有Cl-的污水,而适合降解炼油污水体系。对于焦化废水,COD去除率在40-60%之间,石油类的去除率达到70%左右。对模拟炼油污水,COD最高去除率可以达到85%以上,石油类去除率可达到83.7%。在菌种浓度500μL/L、连续曝气、20℃的优化条件下,上海石化实际炼油污水COD从1034mg/L降到293mg/L,去除率71.7%；石油类含量从51.6mg/L降到3.3mg/L,去除率93.6%。UBD菌具有快速高效处理炼油污水的能力,相对于其他菌种在摇床培养条件下72～240h的降解时间,该菌48h内就可以达到较好的降解效果。UBD菌对B/C为0.19的难生物降解的炼油污水仍具有较强的降解能力。生物降解过程中体系的pH值呈下降趋势,主要是石油类化合物在酶的作用下生成了低级脂肪酸等小分子酸的缘故。选取聚乙烯醇(PVA)作为凝胶剂,海藻酸钠(SA)、活性碳和SiO2作为助凝剂,硼酸溶液和氯化钙溶液作为交联剂,硫酸钠溶液作为固化剂,采用凝胶包埋法固定化UBD菌,成功实现了UBD菌的固定化,用于炼油污水的处理。最佳的凝胶液配比为：PVASA、活性炭、SiO2的质量分数分别为4%、0.5%、1.5%、1%。优化的交联和固化条件为：6wt%的硼酸溶液和2wt%的氯化钙溶液作为交联剂,0.5wt%的硫酸钠溶液作为固化剂,固化时间为24h,无菌水浸润时间为24h。菌种固定化后明显改善了炼油污水的处理效果,COD和石油类物质的去除率比游离菌都有所提高。固定化小球具有良好的机械强度、弹性、渗透性等物理性质,可以重复利用并保持良好的活性。自行设计并制造了气升式内循环气液固三相流化床反应器,从流体力学角度,综合考虑气含率、液体循环时间、完全混合时间和体积氧传质系数等四方面因素,内循环气液固三相流化床优化的操作条件为：气速180 L/h,固含率5%。在此条件下三相流化床具备优良的流体力学性能,气含率为8.31%,液体循环时间为8s,液体完全混合时间为35s,体积氧传递系数为20.67min-1。结合固定化包埋技术,考察了三相流化床反应器中固定化UBD菌对炼油污水的处理效果,获得了优化的工艺条件：固体颗粒填充率5%,固定化颗粒粒径为3mm,气速180L/h,水力停留时间15h。气升式内循环气液固三相流化床反应器对水力负荷和COD容积负荷的波动有很强的适应能力,容积负荷达到2.56kgCOD/(m3-d),比传统活性污泥法(0.4～O.9 kgCOD/(m3.d))高3-5倍。论文还考察了UBD菌降解石油类物质的动力学,UBD菌降解石油类物质的Haldane底物抑制生物降解动力学方程为(?)其中νmax=0.17h-1,Ks=25.87mg/L,底物抑制常数Ki=672.77 mg/L.说明石油类对于UBD菌已经不是难降解物质,UBD菌能够对炼油污水进行高效的生物降解。本文实现了UBD菌的扩大培养,为UBD菌降解炼油污水的工业应用提供了菌种扩大培养技术的基本保证。UBD菌适宜的培养条件为：接种量3%,溶氧空间80%,温度30℃,摇床速度190rmp,培养基为蛋白胨15 g/L、酵母粉5 g/L.NaCl 1O g/L,培养的UBD菌浓度为13.75×107个/L。利用革兰染色和16SrDNA PCR测序,确定UBD菌为Pusillimonas sp., Alcaligenaceae,Burkholderiales,Betaproteobacteria,Proteobacteria, Bacteria.更多还原

【Abstract】 Study on the biodegradation technology of petrochemical wastewater, improving the waste water purification and cycle utilization level are necessary for saving water resource and practicing the green concept.This paper adopted gas-lift inner-loop gas-liquid-solid three-phase fluidized bed reactor to continually biodegrade petrochemical wastewater with the microorganism UBD immobilized technology. After effectively biodegradation, the Chemical Oxygen Demand (COD) and Total Petroleum Hydrocarbons (TPH) of the petrochemical wastewater from Gaoqiao branch company (Sinopec) decreased from 624 mg/L to 93.6 mg/L and 48.7 mg/L to 2.4 mg/L respectively, the quality of the outlet water met the first grade emission standard of PRC (GB 8978-1996).The adaptability of microorganism UBD to wastewater was firstly investigated through batch experiment, the result showed the microorganism was not suitable for dealing with the wastewater including Cl- but the petrochemical wastewater. For coking wastewater, the removal rate of COD was between 40% and 60%, and that of TPH reached around 70%; for simulated petrochemical wastewater, the removal rate of COD could reach more than 85%, that of TPH could reach 83.7%. Under the optimized condition of microorganism concentration of 500μL/L(V/V), aeration and 25℃, the COD of actual petrochemical wastewater decreased from 1034mg/L to 293mg/L, the removal rate was 71.7%; the TPH decreased from 51.6mg/L to 3.3mg/L, the removal rate was 93.6%. This microorganism had fast and highly efficient ability to deal with the petrochemical wastewater and could reach good degradation effect in 48 hours compared with 72-240 hours of other types of microorganism. Microorganism UBD still had strong degradation ability toward the wastewater, which had B/C of 0.19 and was hard to degrade. The degradation of the UBD on the short chain n-paraffins was faster than long chain n-paraffins. pH of the system during the degradation process intended to fall mainly because of the organic acid generated from the petroleum compound by the effect of enzyme.Microorganism UBD was successfully immobilized by choosing PVA as gelata, sodium alginate, activated carbon and SiO2 as the coagulant aids, boracic acid and calcium chloride solvent as cross linker and sodium sulfate solvent as the solidification agent and adopting the gel entrapment technology to deal with the petrochemical wastewater. The most optimized mixture ratio was:mass fraction of PVA, SA, activated carbon and SiO2 was 4%,0.5%,1.5% and 1% respectively. The optimized cross linkage and solidification condition was:boracic acid solvent of 6wt% and calcium chloride solvent of 2wt% as the linkage agent and sodium sulfate solvent of 0.5wt% as the solidification agent; the solidification and infiltration time of sterilized water was both 24 hours. The effect of the microorganism on dealing with the wastewater was obviously improved with the immobilized microorganism and the removal rate of COD and TPH were increased compared with free microorganism. The immobilized microorganism pellet had better mechanical robustness, elastane and osmosis, could be utilized repeatedly and maintained good activity.The gas-lift inner-loop gas-liquid-solid three-phase fluidized bed reactor was self-designed and constructed. The factors of gas holdup, liquid cycle time, mixing time and volumetric oxygen transfer coefficient were considered from the point of fluid mechanics and the optimized operation conditions for the fluidized bed were:gas velocity of 180 L/h, solid holdup of 5%, under this condition, the fluidized bed had good fluid mechanics performance, which were gas holdup of 8.31%, liquid cycle time of 8s, mixing time of 35s and volumetric oxygen transfer coefficient of 20.67 min-1. The effect of immobilized microorganism UBD on dealing with the petrochemical wastewater in the fluidized bed was investigated and the optimized technological conditions were:solid particle filling rate of 5%, immobilized particle size of 3mm, gas velocity of 180L/h and hydraulic residence time of 15h. The gas-lift inner-loop gas-liquid-solid three-phase fluidized bed reactor had strong adaptability toward the variation of hydraulic and COD volume load, the volume load reached 2.56 kgCOD/(m3·d) which was 3-5 times higher than traditional activated sludge process.The kinetics for the degradation of microorganism UBD on the petroleum compounds was also investigated, the kinetic equation for Haldane substrate inhabiting biodegradation during the degradation of microorganism UBD on the TPH was: in which vmax=0.17b-1, Ks=25.87mg/L and the substrate inhibition constant Ki=672.77 mg/L. which indicated the petroleum compounds were not hard to be degraded for UBD microorganism.The enlarge culture for UBD microorganism was accomplished in this paper, therefore the supply of this microorganism to the petrochemical wastewater industry was guaranteed. The most suitable culture conditions for the microorganism UBD were:inoculum concentration of 3%, dissolved oxygen space of 80%, temperature of 30℃, speed of shaking incubator of 190rmp, the incubation media was peptone of 15 g/L, yeast powder of 5 g/L, NaCl of 10 g/L and the microorganism concentration of 13.75×107个/L. The UBD microorganism was Pusillimonas sp., Alcaligenaceae, Burkholderiales, Betaproteobacteria, Proteobacteria, Bacteria by using gram straining and 16SrDNAPCR sequencing.更多还原