EX-SITU THERMAL TREATMENT OF SOILS FOR THE REMOVAL OF PERSISTENT ORGANIC POLLUTANTS

One of the key tasks in updating the National Action Plan for the implementation of the requirements of the Stockholm Convention on Persistent Organic Pollutants (POPs) in Ukraine is to determine the optimal technical solutions for the treatment of soils contaminated with POPs. Previous experience shows that the use of transportable thermal plants is economically viable with sufficient environmental efficiency. Significant prevention of PCDD/PCDF synthesis during the removal of POPs from soil should be ensured by grinding the soil with calcium oxide. The volume of secondary POPs formation also significantly depends on the mode and means of thermal desorption of pollutants from soils. The analysis showed that the worst conditions for the formation of secondary PCDD/PCDF are in desorbers with external indirect heating while maintaining a renewable or neutral atmosphere in the working space of the desorber. Depending on the conditions of use, the transportable plant can be equipped with either a condensation module or a module for the destruction of desorption products. After condensation, the pollutants can be transferred for neutralization to other specialized off-site facilities. When using the destruction module as part of a transportable facility to prevent the formation of PCDD/PCDF, a reducing or neutral atmosphere should also be maintained in it. As a source of auxiliary energy, it is advisable to use plasma sources with a regulated redox potential of the plasma-forming medium. The specificity of some contaminated areas in chemical production is their simultaneous contamination with POPs and mercury. Indirect-action desorbers are able to provide simultaneous effective removal of both POPs and mercury from the soil. Methods for the final neutralization of POPs and mercury after the desorber differ and must comply with the recommendations set out in the reference documents to the Basel and Stockholm Conventions. Bibl. 23, Tab. 1, Fig. 2.