In situ chemical oxidation: Lessons learned at multiple sites

Abstract

This paper compiles a detailed set of in situ chemical oxidation (ISCO) lessons learned pertaining to design, execution, and safety based on global experiences over the last 20 years. While the benefits of a "correct" application are known (e.g., cost effectiveness, speed, permanence of treatment), history also provides examples of a variety of "incorrect" applications. These provide an opportunity to highlight recurring themes that resulted in failures. ISCO is, and will continue to provide, an important remedial tool for site remediation, particularly as a component of a multifaceted approach for addressing large and complex sites. Future success, however, requires an objective understanding of both the benefits and the limitations of the technology. The ability to learn from the mistakes of the past provides an opportunity to eliminate, or at least minimize, them in the future. Over the last 25 years of ISCO application, process understanding and knowledge have improved and evolved. This paper combines a thorough discussion of lessons learned through decades of ISCO implementation throughout all aspects of ISCO projects with an analysis of changes to the ISCO remediation market. By discussing the interplay of these two themes and providing recommendations from collective lessons learned, we hope to improve the future of safe, cost-effective, and successful applications of ISCO.

Cross‐borehole geoelectrical time‐lapse monitoring of in situ chemical oxidation and permeability estimation through induced polarization

“…Monitoring wells are typically used to evaluate both the spread of the oxidizing agent and the degradation of contaminants, but the information that can be achieved with monitoring wells comes with two major limitations: limited lateral resolution and limited vertical resolution (Pac et al ., 2019). The vertical resolution of the monitoring wells is limited by the number and lengths of filters, with large filters averaging large volumes, making it impossible to tell if the oxidizing agent is present in the entire interval or just a part of it.…”

“…One way of addressing these contaminated sites is through in situ chemical remediation, where a remediation agent is injected into the contaminated soil, in order to break down the pollutants (Tsitonaki et al ., 2010). One of the main issues with this type of remediation strategy is ensuring that the injectant spreads throughout the entire targeted volume (Pac et al ., 2019). Traditionally this is verified from a number of monitoring wells with samples taken for chemical analysis in order to determine whether the injectant has reached the well or not.…”

Fenton oxidation for soil remediation: A critical review of observations in historically contaminated soils

“…Soil organic matter is highly heterogeneous with varying proportions of organic phases having different affinities for contaminants. The presence of non-aqueous phase liquids (NAPLs) in soils presents specific challenges to any remediation technique (Pac et al, 2019). Moreover, the entrapment of pollutants in soil voids and pores may also affect their mobility and availability (Figure 1) (Jonsson et al, 2007).…”

“…Similarly, soil mineral fractions and pollution characteristics have also shown strong impact on oxidation efficiency (Jonsson et al, 2007;Pac et al, 2019). Moreover, historically J o u r n a l P r e -p r o o f 5 contaminated soils tend to be near industrial sites (coking industry, gasworks, oil fields, etc.…”

A Quantitative Approach to Assessing the Technical and Economic Performance of Source Containment Options for Contaminated Aquifers

“…When possible, in situ techniques are preferred, since they make it possible to reduce not only the remediation costs and time, but also the depletion of resources [2]. Relevant examples of in situ remediation techniques include chemical oxidation [3][4][5][6], chemical reduction [7][8][9][10], adsorption/immobilization/precipitation processes [11][12][13], enhanced bioremediation [14,15], and electrochemical treatments [16][17][18].…”