Thermal desorption of chemical warfare agents surrogate from polluted materials: from laboratory to pilot scale

The persistent threat of attack by chemical warfare agents should lead security and rescue services both to avoiding or minimising their serious acute impacts and rapidly and safely eliminating hazardous contaminated material. Low-volatile chemical warfare agents can be treated by thermal desorption that is efficient, versatile and easily available technology for solid waste remediation. We studied the application of thermal desorption technology, using diethyl phthalate as an appropriate chemical warfare agents surrogate. The conventional concept of indirectly heated material by thermal conduction was extended by innovative microwave heating in this study. In laboratory tests, the efficient desorption temperature was evaluated for six different spiked matrices. In addition, the technology using both heating approaches was verified in developed pilot-scale apparatuses for the treatment of several tens of kg of two material samples. For the diethyl phthalate removal, the mild conditions of 250 °C temperature were efficient in all experiments, with the temperature being a driving parameter for desorption. We observed insignificant differences in removal efficiency in various matrices or with differently applied heating methods; all residual concentrations were less than the detection limit. The achieved results confirmed the high potential of thermal desorption technology implementation in handling material contaminated by chemical warfare agents.