Zhejiang, China: Thermal Remediation at a Former Pesticide Plant

GEO used Gas Thermal Remediation at a former pesticide manufacturing site in Zhejiang, China. The target contamination included persistent organic pollutants, petroleum hydrocarbons, and other volatile and semi-volatile compounds in heterogeneous silty clay.

Thermal remediation equipment at the former pesticide manufacturing site in Zhejiang, China.

The case study describes 230 thermal conduction heater wells across approximately 6,500 square feet, extending to an average depth of 40 feet below ground surface. Heating was integrated with multiphase extraction.

The design used different temperatures for different treatment zones: approximately 210°C for the semi-volatile contaminant zone and steaming temperatures around 100°C for deeper saturated soils containing volatile compounds. Heat was transferred indirectly from the heater wells into soil and groundwater; extraction wells collected the mobilized vapor for treatment.

The source reports 66 days of active heating and contaminant mass reductions greater than 99% in soil and groundwater. The differentiated temperature approach was a central feature of the documented project.