C Herb Ward

Chlorinated Ethene Source Remediation: Lessons Learned

Chlorinated solvents such as trichloroethene (TCE) and tetrachloroethene (PCE) are widespread groundwater contaminants often released as dense nonaqueous phase liquids (DNAPLs). These contaminants are difficult to remediate, particularly their source zones. This review summarizes the progress made in improving DNAPL source zone remediation over the past decade, and is structured to highlight the important practical lessons learned for improving DNAPL source zone remediation. Experience has shown that complete restoration is rare, and alternative metrics such as mass discharge are often useful for assessing the performance of partial restoration efforts. Experience also has shown that different technologies are needed for different times and locations, and that deliberately combining technologies may improve overall remedy performance. Several injection-based technologies are capable of removing a large fraction of the total contaminant mass, and reducing groundwater concentrations and mass discharge by 1 to 2 orders of magnitude. Thermal treatment can remove even more mass, but even these technologies generally leave some contamination in place. Research on better delivery techniques and characterization technologies will likely improve treatment, but managers should anticipate that source treatment will leave some contamination in place that will require future management.

NAPL Removal Surfactants, Foams, and Microemulsions

Demonstration of the Surfactant/Foam Process for Remediation of a Heterogeneous Aquifer Contaminated with DNAPL Executive Summary Description of Surfactant/Foam Process and Surfactant-Enhanced Aquifer Remediation Surfactant/Foam Process Development Surfactant/Foam Field Site Description Field Demonstration Design Field Operations Field Monitoring, Sampling, and Analytical Methods Results Discussion Conclusions References for Surfactant/Foam Demonstration of Single-Phase Microemulsions for Aquifer Remediation Executive Summary Introduction Single-Phase Microemulsion (SPME) In Situ Flushing: Background Phase I: Laboratory Investigation Phase II: Field Investigation Conclusions References for SPME Design and Evaluation of Surfactant/Foam and Single-Phase Microemulsion Technologies Design of a Hypothetical Full-Scale Implementation of the Surfactant/Foam Process Executive Summary Summary of Technology Demonstration Measurement Procedures Engineering Design Cost and Economic Analysis Performance and Potential Application References Design and Evaluation of a Full-Scale Implementation of the Single-Phase Microemulsion Process Executive Summary Summary of SPME Demonstration Measurement Procedures Engineering Design Cost and Economic Analysis Performance and Potential Application References Appendices

Chlorinated Solvent Source Zone Remediation

Inevitably, reading is one of the requirements to be undergone. To improve the performance and quality, someone needs to have something new every day. It will suggest you to have more inspirations, then. However, the needs of inspirations will make you searching for some sources. Even from the other people experience, internet, and many books. Books and internet are the recommended media to help you improving your quality and performance.

Bioaugmentation with Dehalococcoides: a Decision Guide

Bioaugmentation with Dehalocccoides strains has the potential to improve the performance and/or reduce the costs of in situ bioremediation. However, deciding whether the costs of bioaugmentation are justified is often difficult. This chapter is intended to help site managers in this decision-making process. The chapter is structured around a flowchart based on a series of diagnostic questions and site conditions that are critical in determining whether to bioaugment. After introducing the key sources of uncertainty involved in the decision process, the remainder of the chapter describes these diagnostic questions and the key sources of information useful in answering them, including discussions of relevant laboratory and field test methods. This guidance is not intended to be prescriptive in nature, but to present a systematic approach to making a decision that generally requires both technical information on specific site conditions, as well as non-technical judgments regarding risk tolerance and economic assessments. The guidance begins with questions structured as “off ramps,” to allow rapid screening of sites where the decision is relatively easy. Later questions require more detailed information and testing, and the final questions require consideration of management objectives and development of comparative cost estimates.

Habitats and Biota of the Gulf of Mexico: An Overview

An overview of 13 chapters that assess baseline conditions and status of habitats and biota in the Gulf of Mexico before the Deepwater Horizon oil spill in 2010. Brief summaries of water and sediment quality, energy flow—including natural oil and gas seeps, coastal and offshore habitats, major groups of biota and their diseases and mortalities, and commercial and recreational fisheries are provided. Biodiversity in the Gulf is high, but environmental impacts are numerous and varied and most occur within the coastal zone.