Development of technical guidelines for the application of in-situ chemical oxidation to groundwater remediation Renato Baciocchi a, * , Laura D’Aprile b , Ivan Innocenti c , Felicia Massetti c , Iason Verginelli a a Laboratory of Environmental Engineering, Department of Civil Engineering and Computer Science Engineering, University of Rome “Tor Vergata”, Rome, Italy b ISPRA, Institute for Environmental Protection and Research, Italy c Eni R&M, Research and Development Unit, Rome, Italy article info Article history: Received 26 July 2013 Received in revised form 6 December 2013 Accepted 6 December 2013 Available online xxx Keywords: ISCO Contaminated sites Groundwater remediation Guidelines abstract 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 na- tional 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 inter- pretation, 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 appli- cation 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. Ó 2013 Published by Elsevier Ltd. 1. Introduction In-Situ Chemical Oxidation (ISCO) represents a relevant tech- nological option for the clean-up of groundwater contaminated by organic compounds, such as hydrocarbons, PAHs, PCBs, chlorinated solvents and explosives. The remediation using ISCO involves injecting oxidants into the subsurface to destroy the different organic compounds of concern (ITRC, 2005). Oxidant delivery is commonly accomplished through permeation by vertical direct- push injection probes or flushing by vertical groundwater wells even though other delivery methods, such as horizontal wells, infiltration galleries, soil mixing and hydraulic or pneumatic frac- turing, are also employed (Siegrist et al., 2011). There are several different oxidant formulations that are used for ISCO application. The most commonly applied ones are based on hydrogen peroxide, potassium or sodium permanganate, sodium persulfate, ozone or a combination of them. In particular, the application of chemical oxidation in soil and groundwater environments was initially focused on the use of catalyzed hydrogen peroxide using the classic Fenton’s process, based on the reaction of hydrogen peroxide with ferrous ions to generate a wide variety of radicals by adding iron sulphate. In their pioneering work, Watts et al. (1990) proposed the application of classic Fenton’s reagent for the treatment of soils contaminated by pentachlorophenols, suggesting optimum pH conditions between 2 and 3. Later, this approach was tested by Ravikumar and Gurol (1994) on sand packed columns contami- nated again by pentachlorophenol but also trichloroethylene. The application of Fenton-like process, based on the concept of using naturally occurring minerals as iron source was first investigated by Watts et al. (1993), whereas Kakarla and Watts (1997) and more recently Watts and Teel (2005) addressed the issue of H 2 O 2 stabi- lization using phosphate salts. This issue was also investigated * Corresponding author. Tel.: þ39 (0)672597022. E-mail addresses: baciocchi@ing.uniroma2.it (R. Baciocchi), laura.daprile@ isprambiente.it (L. D’Aprile), Ivan.Innocenti@eni.com (I. Innocenti), Felicia. Massetti@eni.com (F. Massetti), verginelli@ing.uniroma2.it (I. Verginelli). Contents lists available at ScienceDirect Journal of Cleaner Production journal homepage: www.elsevier.com/locate/jclepro 0959-6526/$ e see front matter Ó 2013 Published by Elsevier Ltd. http://dx.doi.org/10.1016/j.jclepro.2013.12.016 Journal of Cleaner Production xxx (2013) 1e9 Please cite this article in press as: Baciocchi, R., et al., Development of technical guidelines for the application of in-situ chemical oxidation to groundwater remediation, Journal of Cleaner Production (2013), http://dx.doi.org/10.1016/j.jclepro.2013.12.016