The desorption of hydrophobic organic compounds (HOCs) and limited mass transfer in soil systems is a significant challenge for efficient soil remediation by oxidation treatments. The utilization of sonochemistry is a promising technology to enhance the decontamination of HOCs-polluted soils. In this work, ultrasound (US) was coupled to NaOH for activating persulfate (PS) to enhance the remediation of a real soil polluted with hexachlorocyclohexanes (HCHs) (α-HCH=282 mg kg -1 , and β-HCH=110 m kg -1 ). Batch experiments (mass aqueous/soil ratio, V L /W S =2) were performed to evaluate the effect of US on HOCs desorption and oxidation. Moreover, the influence of US power (0, 20, 65, 165, and 245 W), and the initial oxidant concentration (C PS =10, 20, 40, and 60 g L -1 ) on pollutants abatement, dechlorination degree, and oxidant consumption have been studied. The US application enhances the desorption of trichlorobenzenes (TCBs) (generated from HCH alkaline hydrolysis) from the soil, favouring their subsequent oxidation because of the formation of higher concentrations of radical species and the temperature rise. An increase in the US power up to 165 W accelerates the production rate of radicals, improving the pollutants degradation. The difference between pollutant oxidation and dechlorination decreases with increasing US power, associated with a lower concentration of intermediate chlorinated compounds. In the same way, the initial oxidant concentration plays a fundamental role in the remediation treatment. At the selected operating conditions (V L /W S =2, C PS =60 g L -1 , NaOH/PS=2, 165 W), a pollutants degradation and dechlorination above 0.94 and 0.74, respectively, were achieved in just 3 h of reaction time
