A comprehensive review of recent and perspective technologies and challenges for the remediation of oil-contaminated sites

The consumption of oils and related derivatives has dramatically increased during the period of rapid development of global industrialization and urbanization in the last few decades. In the process of petroleum extraction, transportation, processing and utilization, the leakages of petroleum into soils are almost inevitable, due to imperfect management, incomplete combustion, leakage from aging pipelines and other accidental factors. Owing to the certain toxicity of petroleum and related derivatives, petroleum pollutants in soils can cause serious local environmental and human health issues. Consequently, effective soil remediation technologies of oil-contaminated sites are crucially demanded for sustainable development and environmental safety. This review introduces the current situation of oil-contaminated sites, and discusses various soil remediation strategies and corresponding treatment mechanisms. In addition, the advantages and limitations of every remediation technology are summarized in detail. Generally speaking, although physical remediation and chemical remediation have the advantage of short operation time, exorbitant operating cost, complex equipment and suitable chemicals are required. However, owing to the complexity of contaminated site conditions, single remediation technology cannot satisfy all types of oil-contaminated sites. Meanwhile, biological remediation and combined remediation technologies are highlighted, which are the direction of future development trend under complex pollution conditions of oil-contaminated sites. Finally, challenges in remediation of oil-contaminated sites such as soil variation, site conditions, site responsibility, remediation funding and future development recommendations are discussed, which might provide new horizons and reference information for future soil remediation work of oil-contaminated sites.