Like other industrialized nations, groundwater supplies beneath many industrial sites in Sweden are contaminated with chlorinated solvents. Compared to countries in North America and other parts of Europe, however, chlorinated solvent impacts in Sweden have not attracted much attention until recently.
In 2005, the Swedish Environmental Protection Agency (Naturvårdsverket) recognized the need for national guidance on chlorinated solvent remediation. To meet this need, Swiss officials commissioned a project for the development of a Technical Manual for Screening and Selecting Technologies for Remediation of Chlorinated Solvents in Soil and Groundwater. They also selected an international team of experts – comprised of practitioners from SWECO VIAK (Sweden), Geosyntec Consultants (United States and Canada), and COWI A/S (Denmark) – to write the manual.
The manual introduces stakeholders, authorities, consultants, and contractors to chlorinated solvent remediation and presents a systematic protocol for evaluating and selecting one or more remediation technologies for a given site. This protocol, modeled after the U.S. Environmental Protection Agency’s guidance on conducting feasibility studies, consists of five steps: (i) development of remedial action objectives (i.e., identify the purpose of remediation); (ii) development of general response actions (e.g., institutional controls, physical containment, or mass removal); (iii) preliminary screening to identify a broad list of feasible and appropriate remedial alternatives; (iv) detailed technology evaluation to identify a focused short list of remedial alternatives; and (v) assembly and detailed evaluation of site-specific remedial alternatives. An example case study is presented to illustrate application of this protocol for a chlorinated solvent site in Sweden.
The manual also includes detailed technical fact sheets for a variety of chlorinated solvent remediation technologies, including excavation, pump-and-treat systems, air sparging/soil vapor extraction, multiphase extraction, in situ flushing, in situ thermal remediation, in situ bioremediation, in situ chemical oxidation, in situ metal-catalyzed reduction, and phytoremediation. Each fact sheet includes information regarding technology treatment mechanisms; applicability to varying geologic terrains; applicability to plumes and source zones; design criteria; costs; and links to key guidance documents available on the Internet.
This first-of-its-kind guidance manual co-authored by Geosyntec is an important step in Sweden’s ability to manage and remediate industrial sites impacted by chlorinated solvents.