EXPERIMENTAL STUDY ON RESTORATION EFFECT OF IN SITU THERMAL DESORPTION IN COKING CONTAMINATED SITES

In-situ gas thermal desorption experiments were conducted on coking sites contaminated by benzene and PAHs. In this paper, the disposal effect and energy consumption of the secondary combustion of organic pollutants reached an optimal state by innovatively combining combustion and extraction and means of the design form with small extraction tube. In the modular design of tail gas and tail water, the combined process of secondary combustion and adsorption of activated carbon, as well as oil-water separation and activated carbon was adopted, thereby enhancing the removal effect of organic pollutants, and reducing the production of waste gas and activated carbon. Through the remediation experiments conducted on a coking contaminated site of 100 square meters, the four heating periods in the thermal desorption process were well-defined, and the remediation duration was about 55 days. After remediation, the concentrations of benzo (a) pyrene and benzene were less than the standard values for screening the second type land according to Soil Environment Quality Risk Control Standard for Soil Contamination of Development Land (GB 36600-2018), and the exhaust emissions conformed to the Comprehensive Emission Standard of Air Pollutants of Beijing (DB 11/501-2017).