Remediation of benzene pollution in groundwater by ISTD technology based on thermal aeration

For groundwater polluted by benzene series, in-situ thermal desorption has the advantages of low cost, no secondary pollution, and high efficiency and simplicity. However, with the increasing complexity of contaminated sites, the corresponding improvement methods have been continuously put into practice. Aiming at the physical properties (relatively low melting point and boiling point) of benzene, an improved "temperature rise+aeration" in-situ thermal desorption (ISTD) technology was proposed. The experiment mainly uses the one-dimensional cylinder and its internal sand filling to simulate the polluted groundwater condition, and the thermal aeration device of a heterogeneous sand layer is used to quantify and evaluate the removal rate of benzene pollution in groundwater. The results show that: 1) the size and distribution of groundwater environmental medium directly control the removal rate of benzene; 2) the variation of ambient temperature is the main external factor for controlling the removal rate of benzene; 3) the appropriate increase of aeration flow can accelerate the escape of benzene; 4) with the continuous extension of thermal aeration time, the removal rate of benzene under any heterogeneous combination in groundwater environment will gradually increase until 12 h later, and the average removal rate can reach more than 90%.