Combined Chemical-Biological Method for Efficient Clean Treatment of Oily Sludge

The long-term heavy dependence of human beings on petroleum products has led to a large amount of oily sludge discharge, and improper treatment of oily sludge will seriously pollute the environment and ultimately affect human health. However, the composition of oily sludge is too complex and difficult to treat. In this study, a new method for the joint treatment of oily sludge with surfactants and microorganisms was utilized, in which the organic matter in the oily sludge was eluted by the surfactants, and the residual organic matter, which was difficult to be eluted, was further degraded by microorganisms. This combined chemical-biological treatment method significantly improved the degradation efficiency of the oily sludge, and reduced the Total petroleum hydrocarbon (TPH) content of the oily sludge from 52,400 mg/kg to 4,190 mg/kg, with a TPH removal rate of 92%, and the residual oily sludge had a TPH content of 1.43%, which was already in compliance with the emission standards. The mechanistic analysis in this study also showed that the addition of appropriate amount of inorganic salt can promote the formation of surfactant micelles and significantly improve the elution effect of surfactant. This study will provide a useful reference for the efficient green treatment of oily sludge.