Sustainable Remediation of Polluted Soils from the Oil Industry Using Sludge from Municipal Wastewater Treatment Plants

Soil pollution with hydrocarbons is a consequence of the activity of the oil industry and other related fields of activity. The effects of oil pollution are devastating; therefore, the remediation of polluted sites is mandatory. For this reason, soil decontamination is a major and expensive problem for the oil industry. The article proposes a dual-recovery bioremediation solution that is efficient and inexpensive. The possibility of using sludge resulting from municipal wastewater treatment plants for the treatment of soils contaminated with petroleum was studied. During the bioremediation experiment, the variation over time of the density of indigenous bacteria present in the mixtures of contaminated soil and sewage sludge, in various proportions was followed, simultaneously with the decrease in the concentrations of petroleum hydrocarbons. In parallel, the evolution of other pollutants from the two environments was analyzed, such as heavy metals (ICP - MS), etc. The study also includes geotechnical tests for returning the soil after bioremediation to the original locations. The obtained results lead to the conclusion that the proposed method can simultaneously solve both the problem of remediation of soils polluted with petroleum products (hazardous waste) and the recovery of sludge from municipal wastewater treatment plants.