Combining ISCO and ISS for Enhanced Remediation
This white paper explores the integration of In Situ Chemical Oxidation (ISCO) and In Situ Stabilization/Solidification (ISS) into a single application for soil and groundwater remediation. ISCO uses powerful oxidants to destroy contaminants, while ISS immobilizes them within a stabilized soil matrix. Combining these technologies delivers synergistic benefits, including reduced leachate concentrations, improved unconfined compressive strength (UCS), lower hydraulic conductivity (K), and minimized soil bulking. The paper presents design considerations, performance data, and evidence from Srivastava et al. (2016) demonstrating cost-effective, sustainable remediation outcomes.

This white paper examines the generation and implications of sulfate residuals following the use of KLOZUR® activated persulfate for in-situ chemical oxidation (ISCO). It details sulfate formation during contaminant oxidation, its influence on groundwater quality, and regulatory considerations relative to secondary maximum contaminant levels (SMCL). The paper also explores sulfate’s dual role: potential challenges for reductive dechlorination and benefits for anaerobic bioremediation of petroleum hydrocarbons via sulfate-reducing bacteria (SRB). Design strategies, including lime activation to mitigate sulfate concentrations, and the concept of a “combined remedy” leveraging ISCO and enhanced bioremediation, are discussed.

This white paper addresses the challenges posed by 1,4-dioxane, an emerging contaminant frequently associated with chlorinated solvent sites. It reviews dioxane’s environmental behavior—high solubility, mobility, and persistence—and summarizes regulatory drivers and health concerns. Conventional treatment methods for dioxane are largely ex situ and often ineffective for groundwater applications. The paper demonstrates how KLOZUR® activated persulfate provides an effective in-situ chemical oxidation (ISCO) solution for dioxane, while simultaneously treating co-contaminants such as TCA, DCA, and chlorinated ethenes. Laboratory and field data confirm the efficacy of multiple activation methods (heat, high pH, peroxide, chelated iron) and highlight case studies achieving up to 99.9% contaminant reduction.

Application of Activated Persulfate for NAPL Remediation
This White Paper explores the remediation of non‑aqueous phase liquids (NAPLs) in soil and groundwater using KLOZUR® activated persulfate ISCO technology. It highlights the challenges of DNAPLs and LNAPLs, emphasizing oxidant delivery, solution density, and contaminant solubility as critical factors for successful treatment. The paper also reviews activation methods—including heat, hydrogen peroxide, high pH, and surfactants—that enhance contact and contaminant destruction, offering practical strategies for reliable site clean‑up globally.

We explain the effects of oxidation by activated persulfate and its impact on microbial populations. Even with subsequent anaerobic bioremediation, the benefits of reduced impurities and increased naturally dissolved organics will more than offset the effects of increased oxygen levels on the anaerobic population.

Understanding Sulfate Behavior Following Persulfate Application
This White Paper reviews the fate of sulfate residuals generated during in situ chemical oxidation (ISCO) with KLOZUR® persulfate. It presents laboratory and field data showing how sulfate concentrations initially rise in groundwater injection zones but typically decline within six months due to dilution, dispersion, and microbial reduction by sulfate‑reducing bacteria (SRBs). The paper also highlights secondary effects such as sulfide formation and mercury precipitation, offering insights into the geochemical processes that govern sulfate attenuation and long‑term groundwater quality.

The use of activated persulfate for in situ or ex situ treatment of soils contaminated with
PCB contaminated soils has been explored as an alternative to the standard chlorination process of excavation and removal.

Managing Residual Persulfate in Groundwater Sampling and Analysis
This White Paper examines the stability of activated persulfate in subsurface environments and its impact on contaminant analysis in groundwater samples. It discusses how persulfate longevity enhances remediation effectiveness by extending oxidant contact time, while also highlighting potential analytical challenges caused by residual persulfate during laboratory transport and testing. The paper reviews mitigation strategies such as sample handling protocols, extraction methods, and stabilizer addition (e.g., ascorbic acid) to minimize contaminant loss, providing practical guidance for accurate monitoring and reliable site assessment globally.

Thermal Activation of Persulfate Using Electrical Resistive Heating
This White Paper details the use of electrical resistive heating (ERH) to activate KLOZUR® persulfate for in situ chemical oxidation (ISCO). It explains the principles of thermal activation, contrasts it with other activation methods such as high pH, metals, and hydrogen peroxide, and highlights the advantages of controlled sulfate radical formation at moderate subsurface temperatures. Field data from a large‑scale project demonstrate successful remediation of pentachlorophenol (PCP) in a petroleum hydrocarbon matrix, with contaminant concentrations reduced below clean‑up levels and sustained performance observed post‑treatment.

Applying CSIA to Improve ISCO Monitoring and Project Management
This White Paper explores the use of compound specific isotope analysis (CSIA) as a powerful tool to evaluate and optimize in situ chemical oxidation (ISCO) performance. It explains how CSIA distinguishes true contaminant destruction from non‑destructive processes such as dilution, displacement, or rebound, providing more definitive insights than concentration data alone. Field applications demonstrate how CSIA enhances performance monitoring, identifies delivery limitations, and supports better project management decisions, ultimately improving treatment efficiency and accelerating site closure.

The U.S. Department of Homeland Security (DHS) has published a new rule that establishes risk-based performance standards for the security of the nation's chemical facilities. The implications of this rule for the purchase, storage, and use of environmental chemicals and products are explored.

The issue is the measurement of persulfate in groundwater. In this context, the determination of persulfate concentration in groundwater after in-situ application is crucial for the determination of parameters such as the achieved persulfate radius of influence (ROI) and the persulfate residence time in the contaminated zone. 

Professor Neil Thomson explains the concept of natural oxidant interaction as a tool to better understand oxidant requirements at a given site. Neil's research interests focus on the environmental behavior of contaminants in subsurface systems, including immiscible fluids, vapors, and pathogens, the development and application of simulation tools, and the development and evaluation of soil and groundwater remediation technologies.

Frank Sessa of the Environmental Solutions Team has expertise in "chemical oxidation" and "aerobic bioremediation" and explains how to measure oxidation-reduction potential (ORP). 

We provide safety information for handling peroxides. With the right precautions, peroxygens have been safe to use for soil and groundwater remediation for many years. 

This white paper features the problematic class of contaminants, specifically chlorinated ethanes and 1,1,1-TCA, and how to deal with them. Guest authors Michael Marley and Dr. Brant Smith of XDD discuss the treatment of these contaminants.

We make you understand the physical and chemical properties of KLOZUR SP. This is crucial in order to safely and successfully prepare persulfate solutions for injection.

Determining the oxidant requirement of KLOZUR® persulfate for a particular site is critical and is the focus of this issue.