高结垢采油污水中假单胞菌属微生物表面矿化机理及对策研究

As an effective and dependable oil produced-sewage treatment, the bioremediation technology has been widely used in petroleum-production. But it was found, by practice experience, that during the microbial process, calcium sulfate crystal in produced-water is apt to aggregate and deposit on surface of microorganisms, which prevent the matter and energy exchange process with environment, and impact treatment efficiency and result in turn. In order to reveal the deposition mechanism of calcium sulfate crystal on microorganism surface, and conduct a method to avoid calcium sulfate deposit effect on microbial treatment of oil produced-sewage, the oil-sewage from Yanchang oil-field of Northern Shaanxi and Pseudomonas of Microorganism was used in this research. The oily-sewage treatment model will be conducted with Sewage and Pseudomonas of Microorganism in Miniature constant temperature crystallization reactor. The dynamic monitoring system of surface mineralization of Pseudomonas of microorganism will be set up by aggregation of infrared microspectrography, X- diffraction, Low temperature freezing scanning electron microscopy (SEM) and Transmission Electron Microscope(TEM), in order to discuss interaction mechanism between deposition and microorganism and provide theoretical basis for countermeasure propose. Based on the research above and combined with association study of mineralization kinetic process and microbial activity, the promised chemical pretreatment and microorganism integrated sewage treatment method will be found. This research not only has important practical significance on microorganism oil sewage treatment, but theoretical significance on study of mineralization mechanism of microorganism.

微生物处理技术作为处理石油废水污染有效且可靠的方法，已在我国石油工业中获得规模化应用。然而，在实践中发现，在微生物处理工艺中，污水中的硫酸钙晶体易在微生物表面聚集、沉积，阻碍微生物与外界物质及能量的交换过程，影响处理效率及效果。为揭示硫酸钙在微生物表面沉积机理，针对性构建缓解硫酸钙沉积对微生物水处理产生的不利影响的有效方法，本课题以陕北延长油田采油污水及假单胞菌属微生物为对象，以污水与假单胞菌属微生物在恒温结晶反应器作为污水处理模型，利用显微红外光谱、吸附聚集X-衍射技术、低温冷冻扫描电镜及透射电镜分析技术对微生物表面沉积物动态监测，揭示沉积物与微生物相互作用机理，为建立针对性应对方法提供理论依据；以此为基础，结合以结垢动力学过程与微生物活性关联性研究，建立化学预处理与微生物相结合的污水处理新工艺。该研究不仅对于石油微生物污水处理具有现实意义，而且对于微生物矿化机制研究也具有重要理论价值。

微生物法处理采出水技术已经逐渐受到关注并小规模应用于油田采出水处理中，但非同层、配伍性差的混合高结垢采出水，垢晶体在菌体表面聚集、沉积，会阻碍菌体与外界环境的物质与能量交换，使微生物处理工艺运行稳定性受到影响甚至瘫痪。.为了探索垢晶体对采出水微生物处理过程的影响规律，建立微生物处理高结垢采出水的预处理技术，项目以油降解率为考察指标，研究了不同硫酸钙结垢量对假单胞菌原油降解能力的影响，通过光学显微镜、透射电镜考察了垢晶体在菌体表面沉积过程；采用黏土、壳聚糖改性黏土颗粒模拟微生物，分析了垢晶体在黏土、壳聚糖改性土颗粒表面沉积规律，构建了沉积过程机制；以诱导期时间、垢晶核形成速率常数、垢晶体长大速率常数为指标，研究了改性土颗粒大小、改性土加量等因素对沉积过程的影响，建立了吸附聚集法测定采出水结垢量的新方法，形成了“吸附诱导+混凝沉淀”除垢方法，优选了除垢技术条件，形成了处理油田非同层、高结垢混合水的微生物法的预处理工艺。.结果表明：（1）铜绿假单胞菌对实验原油中的直链烷烃具有较好的降解效果，在最佳降解条件条件下，元油降解率可达到50%以上。（2）污水中碳酸钙结垢量为983 ～1057 mg/L、硫酸钙结垢量为575 ～1017 mg/L时，垢晶体包裹在菌体表面，原油降解能力减弱。（3）垢晶体在黏土、微生物颗粒表面沉积过程分为表面吸附、聚集、沉积三个阶段。（4）加入壳聚糖改性黏土可降低高结垢模拟水混凝沉淀后的结垢量、缩短垢晶体的沉积时间，实验菌株在结垢量为25 mg/L-745 mg/L的混合水中，原油降解率为50.53 %-56.25 %。（5）形成了“吸附诱导+混凝沉淀”除垢工艺，可使处理后水的透光率为99.18 %，结垢量降低至27 mg/L，铜绿假单胞菌对原油的降解率达到58.15 %。