Bioremediation of petroleum hydrocarbon contaminated soil by microorganisms immobilized on sludge modified by non-ionic surfactant.

The immobilization of microorganisms on high-quality and inexpensive carriers to remediate oil-contaminated soil is an effective strategy for contaminated soil remediation. Due to the abundance in nutrients, large specific surface area, and fewer pathogens, the composting sludge is considered a high-quality immobilized material. Herein, two non-ionic surfactants, TW-80 and sophorolipid, were used to modify composted sludge. High-efficiency petroleum hydrocarbon-degrading bacteria groups selected in the laboratory were fixed on the modified composting sludge under optimal conditions. The immobilized material was placed in the soil contaminated by petroleum hydrocarbons at an additive amount of 2wt/%, and a simulated remediation experiment was performed for 90 days. Both soil properties and microbial structure were characterized. Surfactant-modified compost sludge enhances the adsorption capacity to petroleum hydrocarbon. The immobilized microorganisms in the modified compost sludge showed a good effect on the remediation of soil contaminated by petroleum hydrocarbons. In addition, immobilized materials also increase the diversity of the microbial community structure in the soil. High-efficiency petroleum hydrocarbon-degrading bacteria immobilized on surfactant-modified compost can effectively promote the degradation of petroleum hydrocarbons in the soil and increase the abundance of microorganisms in the soil. It shows the feasibility of eco-friendly remediation of hydrocarbon-contaminated soil.