Remediation of petroleum hydrocarbon-contaminated groundwater by biochar-based immobilized bacteria

Abstract

It is essential to research the technology for effective remediation of petroleum hydrocarbon-contaminated groundwater because the petroleum hydrocarbon contamination of groundwater is becoming more and more serious. The petroleum hydrocarbon-degrading bacteria screened in this experiment were identified as Pseudomonas spp. by 16 S rDNA sequencing. Using wheat straw biochar as the carrier, a highly stable immobilized bacteria integrating adsorption and degradation was prepared by microbial immobilization technology. The results of scanning electron microscopy and Fourier transform infrared spectroscopy analysis showed that the microorganisms were adsorbed on the biochar. Degradation of petroleum hydrocarbon by immobilized bacteria conformed to the second-order kinetic model. For the manufacture of immobilized bacteria, the following immobilization parameters worked best: immobilization pH of 7 and immobilization time of 24 h. Finally, the produced immobilized bacteria were added to four groundwater samples with various initial concentrations of petroleum hydrocarbon, and it was found that all of the petroleum hydrocarbon degradations were above 95%. The study can serve as a useful resource for groundwater petroleum hydrocarbon remediation technology since the immobilized bacteria can successfully adapt to the groundwater petroleum hydrocarbon environment and significantly reduce the concentration of petroleum hydrocarbon.