In this study, the method combining hydrothermal treatment (HT) and in-situ mechanical compression (MC) is used to treat oily sludge. The possible transfer and reaction pathways of different oil components during the process of HT&MC were investigated. In addition, the leaching toxicity, distribution, and risk of heavy metals in oily sludge treated in different temperatures and residence times were evaluated. The results revealed that siloxane and heavy oil components are left in the solid residue, and the light oils and oils with hydrophilic groups are transferred to hydrothermal fluids. The content of Cd, Cr, Pb, and Zn in form of F4 (residual) in the solid residue obtained at a hydrothermal temperature of 240 °C and residence time of 60 min increased by 7.37%, 1.21%, 3.06%, and 9.97%. This reduced the biological availability and environmental risk of heavy metals in the treated oily sludge. Meanwhile, the result of FT-IR illustrated an increase in hydroxyl groups of alcohols, phenols and organic acids, which have a beneficial effect on the adsorption of heavy metals and other pollutants. All results indicated that HT&MC might be a suitable pretreatment method for the stabilization of heavy metals in oily sludge.

本研究采用水热处理（HT）和原位机械压缩（MC）相结合的方法处理含油污泥。研究了HT&MC过程中不同油分可能的转移和反应途径。此外，评估了在不同温度和停留时间处理的含油污泥中重金属的浸出毒性、分布和风险。结果表明，硅氧烷和重油组分留在固体残渣中，轻油和带有亲水基团的油转移到热液中。水热温度240℃、停留时间60min得到的固体残渣中Cd、Cr、Pb、Zn以F4（残渣）形式的含量分别增加了7.37%、1.21%、3.06%和9.97 %。这降低了处理过的含油污泥中重金属的生物有效性和环境风险。同时，FT-IR结果表明醇类、酚类和有机酸的羟基增加，有利于重金属等污染物的吸附。所有结果表明，HT&MC 可能是稳定含油污泥中重金属的一种合适的预处理方法。