Development of technical guidelines for the application of in-situ chemical oxidation to groundwater remediation

In-Situ Chemical Oxidation (ISCO) is an effective technology for the remediation of sites contaminated by a wide range of organic contaminants. Despite it is a well-established technology in the United States, the number of full-scale ISCO application in Europe and particularly in Italy is still quite low. The introduction of ISCO in the portfolio of remediation technologies suitable for the Italian market, specifically for national priority contaminated sites, has been facilitated by the issue of technical guidelines for ISCO application in 2005. Although execution of a pilot-scale test was foreseen in the guidelines, no specific indication or requirements on its design, nor indications or suggestions on its monitoring and interpretation, were provided. In order to give an answer to these issues, a new protocol providing more detailed technical indications with specific attention to the inclusion of the key criteria for ISCO application and for the execution of both lab-scale and pilot-scale feasibility test was developed. This paper discusses the main features of the proposed new protocol. The typical site conditions more suitable for ISCO application are discussed first, making reference to the hydro-geological characteristics of the site, the chemical properties of the contaminated matrix and the characteristics of the target contaminants. Besides, the main indications to perform lab-scale and pilot-scale feasibility tests are discussed. Finally, three sites in which the developed feasibility test procedure was applied are presented. For two of the three sites, in situ pilot tests were also carried out and the obtained results are briefly described in the Appendix of the paper.