磁-MBR耦合工艺深度处理船舶含油污水机理及膜污染控制研究

In order to reduce the damage of ship oil wastewater discharging to sea water, a novel combined process of magnetic system and MBR was conducted for advanced treatment of ship oli wastewater.The aim of this research is to enhance the oil wastewater remvoal rate and stable operation. By molecular biological techniques, the molecular diagnosis of the high efficiency flora for oil remvol was conducted, and the effect of magntic technology on high efficiency flora growth, enzymatic activity, gene mutation, and oil removl was also studied by static experiments by changing the influcence factors, including magnetic field intensity, magnetic action time, and so on, which helps to understand the mechanism of magnatic enhanced superior mixed flora for oil removal based on regulation of enzyme. After the superior mixed flora inoculated in to MBR process, both the characteristics variation of superior mixed flora and activated sludge were analyzed by magnetic system at different operating condition. By analying of characteristics of actived sludge and microbactreia, and membrne system operation situation, the research on formation of the membrane fouling process according to the dynamic process was conducted and the logical relationship between membrane fouling and the characteristics of actived sludge and biologicial activeity by magnetic strengthening was built based on a 3-stage proces of membrane fouling study, which helps to understand the mechanism of membrane fouling control by both magnetic separation and magmatic bioeffect. The study on magnetic system and MBR technology for ship oil wastewater treatment provides a reference for its industrial application.

针对船舶含油污水需在船体上就地处理达标后排放的迫切需要,项目提出了磁-MBR深度处理工艺,目标是提高船舶含油污染物去除的高效性与工艺运行的稳定性。研究内容:将磁过滤、磁生物技术与MBR工艺耦合,利用分子生物学技术进行高效除油混合菌群落的分子诊断，通过调节磁场强度、磁作用时间等参数，研究磁作用因素对高效混合菌群生长、酶活性、基因突变和除油效能的影响，揭示基于酶调控体系下磁强化高效混合菌群的除油机理。将高效混合除油菌群接种到磁-MBR工艺中进行动态实验，基于膜污染三阶段控制理论，在不同工艺运行条件下，研究磁过滤与磁生物技术对MBR中污泥特性和微生物特性的影响，结合膜运行与污染特性分析，建立MBR中微生物特性和活性污泥特性变化与不同膜运行阶段中膜组件污染之间相互作用的逻辑关系，从调控污泥混合液性质角度进行磁过滤技术和磁生物技术控制膜组件污染理论研究。

为满足国际海事组织(IMO)制定的船舶含油污水排放标准，减轻船舶含油污水对海洋环境的影响，课题提出了“磁-MBR技术”深度处理船舶含油污水，将磁过滤、磁生物技术与膜生物反应器耦合，探索磁技术改善微生物除油的效能及对膜污染缓解机理，达到提高整体工艺除污染和长期可持续过滤性能的目的。以分离鉴定的不动杆菌菌株B11为研究对象，探索了磁技术对微生物除油性能和影响机理。磁作用最佳方式为磁场强度25mT、磁场刺激时间3-4d，连续刺激的方式。磁场强化微生物生长机理的研究表明，25mT磁场强度下，细胞生长可提前进入对数期，细胞形态保持完整，菌株的活性最大，较未经磁处理的细菌活性提高25.2%，胞内酶(SOD)活性提高12.3%，抵抗外界恶劣环境能力得到增强。以上研究表明磁场是通过在不破坏细胞膜结构的前提下，提高微生物体内酶的活性来影响菌株的生长的。磁场强化微生物摄取油类物质途径的研究表明，在低磁场强度 (25mT)下，细胞的疏水性得到加强；每100mL菌液产生的表面活性剂数量相比与未经磁场处理组提升17.57%，但磁场对表面活性剂本身的性质没有产生影响。说明磁场是通过改变菌株的疏水性和增强表面活性剂的产量来强化菌株对烃类的摄取作用。将磁粉投加到MBR工艺中，形成PM-MBR工艺，长期连续流实验结果表明，PM-MBR出水CODcr始终低于MBR且PM-MBR膜污染速率在改变曝气强度与增加停抽时间情况下均低于MBR工艺。通过扫描电镜、三维荧光光谱和傅里叶红外光谱分析对膜表面污染分析表明，磁粉减少了胞外聚合物在膜表面的积累，减缓反应器内蛋白质类以及腐殖酸的积累进而减缓膜污染。磁粉投加对活性污泥特性的分析表明，磁粉刺激微生物生长，使得活性污泥浓度升高较快。磁粉产生的弱磁场可以刺激微生物体内酶活性代谢有机物速度加快，从而使反应器内致膜污染物质EPS与SMP的含量与常规MBR反应器相比处于较低水平。磁粉投加可以减小污泥混合液粘度，ZETA电位绝对值，同时改善污泥絮体结构使活性污泥絮体较大且紧实，具有更好的污泥沉降性，这些指标的改善对膜污染速率的减缓起到了重要作用。课题从调控污泥混合液性质角度进行磁技术改善微生物除油性能和控制膜组件污染理论研究，为建立一种科学的，创新而具有实际应用价值的MBR工艺高效除污染及稳定运行提供理论了支撑。