Microbial Community Structure In Oil Field Waste Water Treatment System

The oilfield produced water is a class of special waste water, which comes from the depths of the strata and contains a large amount of crude oil and mineral composition. At present, the majority of oilfield produced water is used for re-injection directly after treatment, and oil content and suspended solids become major control targets. Biological treatment is the most cost-effective approach, to investigate the microbial communities in produced water from biological treatment system and realize the composition of the efficient oil degradation flora, so as to provide a basis for better use of biological treatment technology.This thesis is based on oilfield wastewater biological contact oxidation treatment system, which was build under indoor simulated conditions, and use DGGE, building the clone library and other molecular biology techniques to study the microbial community characteristics of the oilfield wastewater treatment system, and the main results are as follows:1) A and B are two sets of parallel-run oil field wastewater treatment system, which were inoculated with different inocula. Collected sludge samples at regular intervals with the process going on, and used DGGE and clone library to analysis of microbial communities. The results indicated that the microbial community in the two system changes accordingly with the extension of the system uptime; Second, when the system is stabe, the microbial community within the system also showed high stability, yet it didn’t showed significant change with a result of changes in wastewater quality; With the extension of system running time, the two systems showed a similar succession trends.2) The efficient oil degradation flora that can be long term survival in oil production water treatment systems mainly include four categories of microbes-Proteobacteria, Bacteroidetes, Planctomycetes and Chloroflexi. Among them, α-Proteobacteria microbes, which attached to genus Proteus, with the system running constantly, the proportion and diversity are increasing, and they accounted for the dominant position of the preponderant flora gradually.3) In the bio-contact oxidation system, the major oil-degrading microorganisms include Devosia、Rhodobacter、Seohaeicola、Acidovorax、Roseovarius、Brevundimonas、Marinobacter and Sphingosinicella.4) Microorganisms that have ability of oil degradation are mostly uncultured microbes.