In situ chemical oxidation is a developing class of remediation technologies in which organic contaminants are degraded in place by powerful oxidants. Successful implementation of this technology requires an effective means for dispersing the oxidant to contaminated regions in the subsurface. An oxidant delivery technique has been developed wherein the treatment solution is made by adding an oxidant to extracted groundwater. The oxidant-laden groundwater is then injected and recirculated into a contaminated aquifer through multiple horizontal and/or vertical wells. This technique, referred to as in situ chemical oxidation through recirculation (ISCOR), can be applied to saturated and hydraulically conductive formations and used with relatively stable oxidants such as potassium permanganate (KMnO4). A field-scale test of ISCOR was conducted at a site (Portsmouth Gaseous Diffusion Plant) where groundwater in a 5-ft thick silty gravel aquifer is contaminated with trichloroethylene (TCE) at levels that indicate the presence of residual dense non-aqueous phase liquids (DNAPLs). The field test was implemented using a pair of parallel horizontal wells with 200-ft screened sections. For approximately one month, groundwater was extracted from one horizontal well, dosed with crystalline KMnO4, and re-injected into the other horizontal well 90 ft away. Post-treatment characterization showed that ISCOR was effective at removing TCE in the saturated region. Lateral and vertical heterogeneities within the treatment zone impacted the uniform delivery of the oxidant solution. However, TCE was not detected in groundwater samples collected from monitoring wells and soil samples from borings in locations where the oxidant had permeated.

In 1996, researchers at Oak Ridge National Laboratory (ORNL) proposed an oxidant delivery technique involving injection and recirculation of the oxidant solution into a contaminated aquifer through multiple horizontal and vertical wells. This technique would be applicable to saturated, hydraulically conductive formations. In the spring of 1997, the Department of Energy (DOE) at the Portsmouth Gaseous Diffusion Plant (PORTS) agreed to collaborate with the DOE's Subsurface Contaminants Focus Area to conduct a field-scale treatability study using in situ chemical oxidation through recirculation (ISCOR). PORTS agreed to support the demonstration at the X-701B site where the technology can potentially be used to remediate TCE-contaminated groundwater and sediments. The ISCOR field demonstration took advantage of existing infrastructure and extensive site characterization data generated from previous field demonstrations at X-701B. The field test was implemented using a pair of previously installed horizontal wells that transect an area of DNAPL contamination. Groundwater was extracted from one horizontal well, pumped to an existing pump and treat facility, dosed with KMnO4, and re-injected into a parallel horizontal well approximately 90 ft away. The field demonstration lasted approximately one month. Treatment effectiveness was determined by comparing contaminant levels in pre-treatment, during, and post-treatment groundwater samples and pre- and post-treatment soil samples.

This volume provides comprehensive up-to-date descriptions of the principles and practices of in situ chemical oxidation (ISCO) for groundwater remediation based on a decade of intensive research, development, and demonstrations, and lessons learned from commercial field applications.

- Chapter 1: An overview of chemical oxidation including its development and application for in situ treatment of contaminated sites. The oxidation chemistry of Fenton's reagent, permanganate, and ozone are highlighted along with optional methods of oxidant delivery for in situ application. The results of lab-and field-scale applications are summarized.- Chapter 2: A description of the principles and processes of chemical oxidation using potassium or sodium permanganate for organic chemical degradation, including reaction stoichiometry, equilibria, and kinetics, as well as the effects of environmental factors.- Chapter 3: Information provided on the effects of permanganate on the behavior of metals.- Chapter 4: A discussion of the potential for permeability loss and other secondary effects during in situ oxidation using permanganate.- Chapter 5: A description of optional methods of oxidant delivery for in situ remediation.- Chapter 6: A description of a process for evaluation, design, and implementation of permanganate systems.- Chapter 7: A detailed description of five different applications of an in situ chemical oxidation using potassium or sodium permanganate.- Chapter 8: Highlights of the current status and future directions of this remediation technology.

Approximately 85% of the hazardous waste sites in the United States have contaminated ground water. The conventional approach for remediating contaminated ground water has been to extract the contaminated water, treat it above ground, and reinject or discharge the clean water ("pump- and-treat"). The recovered contaminants must be disposed of separately. It is becoming increasingly apparent that pump-and-treat technologies require considerable investment over extended period of time, and often times do not actually clean up the source of the contamination. Current policies and law stress "permanent" remedies over containment. Consequently, there is considerable interest and effort being expended on alternative, innovative treatment technologies for contaminated ground water. This report is one in a series that document recent pilot demonstrations and full-scale applications that either treat soil and ground water in place or increase the solubility and mobility of contaminants to improve their removal by other remediation technologies. It is hoped that this information will allow more regular consideration of new, less costly, and more effective technologies to address the problems associated with hazardous waste sites and petroleum.

The purpose of this book is to help engineers and scientists better understand dense nonaqueous phase liquid (DNAPL) contamination of groundwater and the methods and technology used for characterization and remediation. Remediation of DNAPL source zones is very difficult and controversial and must be based on state-of-the-art knowledge of the behavior (transport and fate) of nonaqueous phase liquids in the subsurface and site specific geology, chemistry and hydrology. This volume is focused on the characterization and remediation of nonaqueous phase chlorinated solvents and it is hoped that mid-level engineers and scientists will find this book helpful in understanding the current state-of-practice of DNAPL source zone management and remediation.

Part of Groundwater Set - Buy all six books and save over 30% on buying separately! This book reviews the state-of-the-art of groundwater management in large river basins, providing an innovative, informative and consistent approach with technical tools for planners, decision makers and engineers. Groundwater Management in Large River Basins provides comprehensive coverage of the basic elements of groundwater management in large river basins, including: Social, economic and legislative framework, goals, practices and possible tools Review of EU groundwater legislation and its implementation Natural groundwater occurrence and natural circumstances and processes Groundwater management and maintenance issues: Role of natural factors in groundwater management Different methods of groundwater abstraction and protection Groundwater treatment technologies Well ageing and maintenance Nitrate problems, etc. Groundwater modeling as a tool for groundwater assessment Aquifer restoration A spectrum of technical appendices for engineers, which address groundwater issues Also included will be appendices intended to support the work of groundwater engineers. This book will be of interest to groundwater engineers and planners, as well as lecturers and postgraduate and postdoctoral students.