Optimizing the Environmental Performance of In Situ Thermal Remediation Technologies Using Life Cycle Assessment

Abstract

In situ thermal remediation technologies provide efficient and reliable cleanup of contaminated soil and groundwater, but at a high cost of environmental impacts and resource depletion due to the large amounts of energy and materials consumed. This study provides a detailed investigation of four in situ thermal remediation technologies (steam enhanced extraction, thermal conduction heating, electrical resistance heating, and radio frequency heating) in order to (1) compare the life‐cycle environmental impacts and resource consumption associated with each thermal technology, and (2) identify options to reduce these adverse effects. The study identifies a number of options for environmental optimization of in situ thermal remediation. In general, environmental optimization can be achieved by increasing the percentage of heating supplied in off peak electricity demand periods as this reduces the pressure on coal‐based electricity and thereby reduces the environmental impacts due to electricity production by up to 10%. Furthermore, reducing the amount of concrete in the vapor cap by using a concrete sandwich construction can potentially reduce the environmental impacts due to the vapor cap by up to 75%. Moreover, a number of technology‐specific improvements were identified, for instance by the substitution of stainless steel types in wells, heaters, and liners used in thermal conduction heating, thus reducing the nickel consumption by 45%. The combined effect of introducing all the suggested improvements is a 10 to 21% decrease in environmental impacts and an 8 to 20% decrease in resource depletion depending on the thermal remediation technology considered. The energy consumption was found to be the main contributor to most types of environmental impacts; this will, however, depend on the electricity production mix in the studied region. The combined improvement potential is therefore to a large extent controlled by the reduction/improvement of energy consumption.

Environmental Impact Assessment of Remediation Strategy in an Oil Spill in the Ecuadorian Amazon Region

“…Other studies have also reported a significant contribution to the impact in this category due to the use of fossil fuels [17,39,40]. In this study the environmental remediation implied a total path traveled by a truck of 6194 km, while the van traveled 2744 km.…”

“…In this sense, life cycle assessment (LCA) is an option to evaluate the environmental behavior of products or process. In fact, LCA was previously used for the evaluation of remediation technologies in various scenarios, such as soil pollution by heavy metals, polychlorinated biphenyls and volatile organic compounds (VOC) [14,[16][17][18][19][20][21]. During LCA evaluation, the identification of primary and secondary impacts in remediation technologies is important; primary impacts are those related to residual contamination left in the subsurface during and after remediation, while secondary impacts refer to the consumption of resources and generation of emissions in other stages of the remediation life cycle of the project [14].…”

Multi-criteria assessment tool for sustainability appraisal of remediation alternatives for a contaminated site

“…If the excavation alternative is selected for this site, then results indicate that it is important to investigate whether the environmental impacts of this method can be reduced by methods such as local soil treatment and recycling of treated soil. A study on optimizing the environmental performance of in-situ thermal remediation technologies (Lemming et al 2013) has shown that LCA can be used to identify and test possible environmental improvements to the remediation technology.…”

Thermal Conduction Heating for a 125 ft Deep TCE Source—Multiple Lines of Evidence for Verification of Remedial Goals

“…The energy usage to reach such temperatures typically range from 150 to 600 kWh per cubic meter of material treated, depending on site-specific parameters such as treatment zone size, water content, groundwater flow, COC boiling points, target treatment temperature, and remedial goals. The required energy is typically generated from electricity or fossil fuel, with a substantial carbon footprint (Lemming et al 2013). A clear objective of many thermal projects is to minimize this energy usage.…”