粉煤灰基沸石固定化微生物对低温地区陆地泄漏原油的生物降解机理

Land-based petroleum spills have the characteristics of sudden occurred, large amount and fast speed of leakage, and wide pollution area, which have caused serious lasting damage to terrestrial ecosystems. The study will focus on the in-situ remediation of land-based petroleum spills of Daqing and Liaohe oil field in cold environments of northeast China. Different types of zeolites are synthesized by fly ash which is solid waste of typical thermal power plant in northeast China. The adsorption mechanism of the main pollutants which are alkanes, aromatic hydrocarbons and PAHs of spilled petroleum is elucidated by the analysis of mathematical adsorption model and key influencing factors of absorption efficiency. High efficient cold-adapted petroleum degrading bacteria can be screened and then use 454 high-throughput sequencing and microbial metabolites GC-MS determination to analyze the microbial community composition of petroleum contaminate soil and the pathway of petroleum hydrocarbon biodegradation, and the biodegradable mechanism and the key parameter of biodegradation under cold environments is elucidated. The physico-chemical adsorption and microbial degradation will be organicly combined to reveal the synergetic degradation mechanism of zeolitized fly ash and immobilized oil degradation bacteria to different pollutant components of alkanes, aromatic hydrocarbons and PAHs in land spilled petroleum. The study can provide scientific basis for treatment of land spilled petroleum under cold environments.

陆地原油泄漏事故具有突发性、泄漏量大、泄漏速度快、污染面积广的特点，常对陆地生态系统造成严重的持续性破坏。本项目针对我国东北低温地区大庆油田、辽河油田陆地泄漏原油的原位处理问题，采用东北地区典型热电厂固体废弃物粉煤灰制备不同类型沸石，通过吸附数学模型和吸附效果的关键影响因素分析，阐明粉煤灰基沸石对泄漏原油中烷烃、芳香烃与PAHs等主要污染物的吸附机制；筛选高效低温石油烃降解菌，通过454高通量测序和微生物代谢产物GC-MS测定，分析石油烃污染土壤中微生物群落组成及石油烃生物降解途径，阐明粉煤灰基沸石固定化石油降解菌对陆地泄漏原油的生物降解机理及低温条件下生物降解的关键参数；将物理化学吸附与微生物降解有机结合，揭示粉煤灰基沸石与固定化石油烃降解菌对陆地泄漏原油中烷烃、芳香烃、PAHs等不同污染物组分的协同降解作用机理，为我国低温地区陆地泄漏原油处理提供科学依据。

针对我国东北低温采油区陆地泄漏原油的原位处理问题，采用热电厂固体废弃物粉煤灰制备不同类型沸石，并负载光催化剂g-C3N4制备复合材料；筛选高效低温石油烃降解菌，分析微生物群落组成及石油烃生物降解途径；将物理化学降解与微生物降解有机结合，探究固定化材料与石油烃降解菌联合修复对陆地泄漏原油中不同污染物组分的降解效果，为低温地区陆地泄漏原油处理提供科学依据。主要结论如下：.（1）以粉煤灰为原料，采用碱熔融-水热合成法制备了NaP、NaA、NaX和NaY沸石，其中比表面积最大、毛孔最小、总孔容积最大的NaP型沸石具有最大的吸附能力（0.86 g•g-1柴油）；NaP型沸石负载g-C3N4后保持原有的光催化特性；与粉煤灰合成的NaP型沸石相比，复合材料NaP/g-C3N4能够缩短修复时间，增加修复效率。.（2）低温石油烃降解菌群X-3包括7株单菌，分别来自Pseudomonas sp.（假单胞菌属）、Arthrobacter sp.（节杆菌属）、Rhodococcus sp.（红球菌属）、Bacillus sp.（芽孢杆菌属）和Ochrobactrum sp.（苍白杆菌属）5个不同的菌属；X-3的最适培养的条件为：接种量4%（w/w），石油烃最适浓度12.3 g•L-1，最适氮磷比10:1，最适pH值为7。经过优化实验，X-3对石油烃的降解率从47.75%增加到60.07%，其中短链石油烃更容易被微生物利用，长链以及含支链的烃类污染物的生物降解更困难。.（3）石油烃降解菌X-3经过固定化后投加到石油污染土壤中，微生物不易流失，生物活性增强，显著增加了土壤中总石油烃（TPH）的降解率，此外饱和烃（SH）最容易被微生物利用，而非烃类物质（NH）最难被降解。NaP/g-C3N4固定化降解菌X-3提高了TPH的降解率，且复合材料能够将较长链的石油烃分解为小分子化合物，使得芳香烃（AH）的降解率显著升高。此外，降解烃类菌Pseudomonas sp.（假单胞菌属）、Arthrobacter sp.（节杆菌属）、Acinetobacter sp.（动杆菌属）等所占丰度显著增加，降解菌的群落结构相对稳定，固定化材料不会对其产生不良影响。