Establishment of diesel oil degrading bacteria compounding system and its migration performance in aquifers

Bioremediation is a cost-effective and eco-friendly method to remove diesel oil contaminant from the environment. In this study, six diesel oil-degrading bacteria were isolated and identified from diesel oil-polluted groundwater. The compound bacterial agent was constructed based on antagonistic tests. The target compound bacterial agent NK4/ B29/ C1A showed the highest potential for remediating of 1 g/L diesel pollution groundwater, with a degradation rate of 85.91%. The degradation products had a lower relative content of low molecular semi-volatile organic compounds (C10- C16) compared with their predecessors, presenting a decrease from 79.18% to 0. The results of one-dimensional sand column experiment showed that the injection rate of microbial agents was positively correlated with particle size, while the migration has a better performance under lower ion strength. The increase in ionic strength altered the particle size and electronegativity of the compound bacteria, leading to compression of the double layer and making migration in the aquifer more poor. Additionally, following the injection of a uniformly mixed microbial agent into the aquifer, the phenomenon of bacterial agent separation occurred. The migration ability of Pseudomonas aeruginosa was stronger than that of Alcaligenes fischeri and Pseudomonas guguanensis in the aquifer.