Research On The Waste Oil Mud Degrading Bacteria And Degradation Characteristics

The waste oil mud is mainly consist of waste drilling-mud, waste water and flow-back fluid. It is the mix harmful substance produced during the petroleum and natural gas exploration. The waste oil mud contains large number of harmful substance such as petroleum and heavy metal ion.The study aimed to screening a certain group of strains with the strong ability of harmful substance degradation. Through the metabolism of these strains, harmful substance in the waste oil mud could be degraded and the environment would get better.4strains with high degradation ability were screening from different sources samples. Through the traditional bacterial systemic identification method the4strains were respectively identified as Bacillus, Acinetobacter、Pseudomonas, Rhodotorula.According to the characteristics and degradation ability, the mix strains consist of the4strains was proved to gain better degradation ability. Through the orthogonal experiments, the best proportion was NB-1:NB-2:NB-4:NY-7=3:1.5:2.5:3; The optimal conditions were temperature25℃, processing time30d, inoculation amount1%, auxiliary materials amount0.1%.Through the degradation of the mix strains, the harmful substance in the waste oil mud reduced significantly. After30d degradation, the total content of petroleum hydrocarbons was reduced by76%; the content of Cr6+was decreased by56%; pH was reduced to about7.5; the total amount of microbial reached108/g; the water content changed to about40%. The contaminants and harmful substance in the oil mud were decreased significantly.This research laid a foundation for later site process of oil mud in petroleum and natural gas field.