Demonstration of In Situ Radio‐Frequency Heating at a Former Industrial Site

Abstract

In situ radio‐frequency heating (ISRFH) combined with soil vapor extraction was demonstrated at a contaminated field site of a former hydrotreatment plant in Zeitz near Leipzig. The project was carried out in several phases including cold soil vapor extraction for comparison. During the test, a soil volume of about 300 m3 was heated to an average temperature of 54 °C. As expected, the extraction rate for hydrocarbons (especially the main contaminant benzene) was markedly enhanced by soil heating. Furthermore, microbial degradation of organic compounds was supported. Although a total amount of approximately 1.4 t of hydrocarbons was removed from the soil, the demonstration project was not aimed at complete remediation of the site. Conditions limiting the extent of cleanup are discussed in detail and conclusions for an efficient application of ISRFH in soil remediation are derived whereas experiences from other sites are also implied.

Numerical Estimation of Agricultural Raised Bed Microwave Disinfection

“…At such temperatures, pathogens are completely eliminated in less than 15 to 20 min. However, even if the heating capacity of microwaves is very well known and used for a long time in many different applications, also in the treatment of agricultural foods to extend their durability, very few examples of soil irradiation can be found in the literature (Hansen et al, ), and even less for in situ applications (Holzer et al, ; Krouzek et al, ), if we exclude microwave‐based remediation of organic polluted soils, for which the working temperatures are much higher (O'Brien et al, ). Soil disinfection with in situ MW application using several exposure devices (e.g., horn antennas with pyramidal base and a waveguide feeding (Fanti, Simone, et al, ; Helszajn, ; Simone et al, , ; Spanu et al, ), truncated waveguides (Desogus, Casu, et al, ; Spanu et al, ), or planar slot arrays (Casula et al, ; Casula & Mazzarella, ) has been recognized as a convenient, rapid method of eliminating soil pathogens compared with autoclaving or fumigation (Acierno et al, ; Vitale et al, ).…”