Successful UV/oxidation of VOC-contaminated groundwater

Ultraviolet light/oxidation has proven its effectiveness in destroying volatile organic chemicals (VOCs) found in groundwater during a U.S. Environmental Protection Agency (EPA) field study. Under the Superfund Innovative Technology Evaluation (SITE) program, PRC Environmental Management, Inc., and EPA monitored the performance of a system employing advanced oxidation techniques at the Lorentz Barrel & Drum (LB&D) Superfund site in San Jose, California. The firm of Ultrox International (Santa Ana, CA) demonstrated its technology for combining ultraviolet light, hydrogen peroxide and ozone to oxidize toxic organic chemicals found in water. All evaluation criteria were successfully met in the study's results. Greater than 90% of the VOCs were removed. The applicable discharge standards (National Pollution Discharge Elimination System) were attained, and there were no emissions.     

Remediation and future land use: Incorporating reuse considerations into Superfund activities

The U.S. Environmental Protection Agency (US EPA) is placing increased emphasis on the selection and implementation of remedies that accommodate the reasonably anticipated future use of contaminated land. These remedies result in the long‐term protection of human health and the environment. Postconstruction reuse of the land can significantly benefit communities in other ways as well. The launching of the Superfund Redevelopment Initiative in 1999 and the Return to Use Initiative in 2004 reflects an evolution in the US EPA's understanding of what actions can be taken to support the reuse of Superfund sites from discovery through long‐term stewardship. Through these initiatives, the US EPA has increased its understanding of site reuse and continues to explore and implement reuse assessment, reuse planning, and other tools effective in integrating reuse considerations with response activities throughout the remedial process. © 2005 Wiley Periodicals, Inc.     

Rocky Flats,plutonium, and controversy: Citizen activists provide institutional memory

The U.S. Atomic Energy Commission (AEC) selected Rocky Flats, east of the Rocky Mountains, as the site to fabricate “plutonium pits,” triggers for H‐bombs, and operations began in 1952. Press reports revealed the plant's connection to atomic weapons in 1956. Denver is downwind and “downslope” by about 16 miles. As western suburbs moved closer to Rocky Flats over time, plant accidents sent plutonium and other contaminants offsite. In 1989, armed agents of the U.S. Environmental Protection Agency (EPA) and Federal Bureau of Investigation raided the facility, and the plant operator, Rockwell International, subsequently pleaded guilty to criminal environmental violations. By this time, the U.S. Department of Energy had inherited responsibility for Rocky Flats and atomic weapons production. In 1993, the primary mission at Rocky Flats became cleanup of contamination from plutonium and other hazardous substances. Under Energy's “Accelerated Cleanup” plan, remediation was certified complete in 2005 by the Department's cleanup regulators, EPA, and the Colorado Department of Public Health. But planned uses for the “buffer zone” around the facility's central industrial area, and for off‐site areas continued to generate public controversy. This article examines the controversy and reports on general “stewardship” concepts for long‐term waste management.     

Triad case study: Marine Corps Base Camp Pendleton

The U.S. Navy Public Works Center (PWC) Environmental Department, San Diego, California, is home to the Navy West Coast Site Characterization and Analysis Penetrometer System (SCAPS). SCAPS has been extensively used at several Navy sites since 1995 to provide real‐time, high‐density data sets. The U.S. Environmental Protection Agency's Triad approach provided an ideal framework for optimizing the use of the Navy SCAPS during a volatile organic compound (VOC) source investigation at Installation Restoration Site 1114 at Marine Corps Base Camp Pendleton. All three elements of Triad—systematic planning, dynamic work strategy, and use of real‐time measurement tools—were implemented to manage decision uncertainty and expedite the site management process. The investigation was conducted using the Navy SCAPS, outfitted with a cone penetrometer, membrane interface probe, and a direct sampling ion trap mass spectrometry detector, which allowed for real‐ time collection of over 690 feet of continuous lithologic information and VOC concentration data. These data were used collaboratively with 24‐hour turnaround US EPA 8260B VOC groundwater results from temporary direct‐ push wells to support the conclusion of a limited source area. Implementation of the Triad approach for this investigation provided an expedited high‐density data set and a refined conceptual site model (CSM) in real time that resulted in cost savings estimated at $2.5M and reduction of the site characterization and cleanup schedule by approximately three years. This project demonstrates how the US EPA's Triad approach can be applied to streamline the site characterization and cleanup process while appropriately managing decision uncertainty in support of defensible site decisions. © 2004 Wiley Periodicals, Inc.     

Use of open-path FTIR spectroscopy to address air monitoring needs during site remediations

Although open-path Fourier-transform infrared (FTIR) spectroscopy has been an Environmental Protection Agency (EPA) Toxic Organic Compendium Method since 1996, it has been underutilized as a means to assess exposure to gaseous contaminants during the remediation of hazardous waste sites. This might be considered surprising in light of the many benefits that proper application of this technology can offer. In this article, we provide an overview of the technology and the principle of operation, describe the nature of the data generated, discuss the benefits associated with the technology's use in site clean-up, present emission-rate estimation techniques, and examine the reasons why it has not gained more support over the years. Finally, we present a case study in which the technology was used to drive an 11-month emergency removal action under the direction of the U.S. Environmental Protection Agency.     

A performance history of the base catalyzed decomposition (BCD) process

Remediation of halogenated organic compounds—such as polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs)—poses a challenge because these compounds are resistant to microbial attack and to degradation by many common chemicals. Since the mid-1980s, the Environmental Protection Agency's (EPA's) Office of Research and Development in Cincinnati, Ohio—the National Risk Management Research Laboratory (NRMRL)—has funded research and development efforts to develop specialized, chemical dehalogenation processes for detoxifying PCBs and related compounds. NRMRL owns domestic rights for “basic process” patents on a chemical dehalogenation process commonly known as Base Catalyzed Decomposition (BCD). EPA has licensed the process to two firms for use in the United States. This article summarizes laboratory-scale, pilot-scale, and field performance data on BCD technology collected to date by various governmental, academic, and private organizations.     

Steady‐state field‐scale gas permeability estimation and pore‐gas velocity calculation in a domain open to the atmosphere

Field‐scale estimation of gas permeability and subsequent computation of pore‐gas velocity profiles are critical elements of sound soil venting design. It has been our experience, however, in U.S. Environmental Protection Agency's (EPA's) technical assistance program, provided by the Office of Research and Development in support EPA regional offices, that many venting practitioners are unaware of equations and data interpretation methods appropriate for gas permeability estimation and pore‐gas velocity computation. To ameliorate this situation, we use data collected at a U.S. Coast Guard Station in Traverse City, Michigan, to demonstrate gets permeability estimation and pore‐gas velocity calculation for steady‐state, axisymmetric, two‐dimensional gas flow in a domain open to the atmosphere. For gas permeability estimation, we use random guesses constrained with decreasing intervals of radial and vertical permeabilityand analysis of root mean square errors to ensure attainment of a global versus local minimum. We demonstrate confidence in permeability estimation by providing plots of observed versus simulated pressure response. Finally, we illustrate how plots of pore‐gas velocity as a function of distance and flow rate can be helpful in venting design.     

Treatment technologies for mercury in soil,waste, and water

Mercury occurs naturally in the environment and can be found in elemental (metallic), inorganic, and organic forms. Modern uses for mercury include chemical manufacturing, thermometers, and lighting (mercury vapor and fluorescent lamps). The chemical and allied products industry group is responsible for the largest quantity of mercury used in the United States. Mercury, particularly the organic methylmercury form, is a potent neurotoxin capable of impairing neurological development in fetuses and young children and of damaging the central nervous system of adults. Mercury regulations span multiple federal and state environmental statutes, as well as multiple agency jurisdictions. In August 2007, the U.S. Environmental Protection Agency's (US EPA's) Office of Superfund Remediation and Technology Innovation (OSRTI) published a report titled “Treatment Technologies for Mercury in Soil, Waste, and Water.“ The report identifies eight treatment technologies and 57 projects, 50 of which provide performance data. This information can help managers at sites with mercury‐contaminated media and generators of mercury‐contaminated waste and wastewater to identify proven and effective mercury treatment technologies; screen technologies based on application‐specific goals, characteristics, and costs; and apply experiences from sites with similar treatment challenges. This article provides a synopsis of the US EPA report, which is available at http://clu‐in.org/542R07003 . © 2007 Wiley Periodicals, Inc. *

1 This article is a U.S. Government work and, as such, is in the public domain of the United States of America.

     

Treatment technologies for 1,4‐Dioxane: Fundamentals and field applications

1,4‐Dioxane is a synthetic industrial chemical frequently found at contaminated sites where 1,1,1‐trichloroethane was used for degreasing. It is a probable human carcinogen and has been found in groundwater at sites throughout the United States. The physical and chemical properties and behavior of 1,4‐dioxane create challenges for its characterization and treatment. It is highly mobile and has not been shown to readily biodegrade in the environment. In December 2006, the U.S. Environmental Protection Agency's Office of Superfund Remediation and Technology Innovation (OSRTI) prepared a report titled “Treatment Technologies for 1,4‐Dioxane: Fundamentals and Field Applications.” The report provides information about the chemistry of dioxane, cleanup goals, analytical methods, available treatment technologies, and site‐specific treatment performance data. The information may be useful to project managers, technology providers, consulting engineers, and members of academia faced with addressing dioxane at cleanup sites or in drinking water supplies. This article provides a synopsis of the US EPA report, which is available at http://cluin.org/542R06009 . © 2007 Wiley Periodicals, Inc.     

Evaluating a Site for Natural Attenuation: EPA Region IV's New Guidance

Natural attenuation has recently been recognized by the U.S. Environmental Protection Agency (EPA) as an appropriate remedy for sites contaminated with chlorinated solvents. Because natural attenuation does not require active remediation, it is considerably less expensive than other groundwater remedies. However, as laid out in EPA's recently released guidance, careful, systematic evaluation of natural attenuation must be conducted to ensure that the remedial approach is appropriate for a given site. The guidance requires that data be collected to demonstrate that natural attenuation is occurring and a fate-and-transport model must be conducted to estimate the extent to which a contaminated plume will ultimately migrate. Finally, the proponent of natural attenuation must be prepared to conduct long-term groundwater monitoring to verify that natural attenuation is controlling plume migration and that human health and the environment are not adversely affected.     

Nanotechnology for site remediation

As a remediation tool, nanotechnology holds promise for cleaning up hazardous waste sites cost‐effectively and addressing challenging site conditions, such as the presence of dense nonaqueous phase liquids (DNAPLs). Some nanoparticles, such as nanoscale zero‐valent iron (nZVI) are already in use in full‐scale projects with encouraging success. Ongoing research at the bench and pilot scale is investigating particles such as self‐assembled monolayers on mesoporous supports (SAMMS™), dendrimers, carbon nanotubes, and metalloporphyrinogens to determine how to apply their unique chemical and physical properties for full‐scale remediation. There are many unanswered questions regarding nanotechnology. Further research is needed to understand the fate and transport of free nanoparticles in the environment, whether they are persistent, and whether they have toxicological effects on biological systems. In October 2008, the U.S. Environmental Protection Agency's Office of Superfund Remediation and Technology Innovation (OSRTI) prepared a fact sheet entitled “Nanotechnology for Site Remediation,” and an accompanying list of contaminated sites where nanotechnology has been tested. The fact sheet contains information that may assist site project managers in understanding the potential applications of this group of technologies. This article provides a synopsis of the US EPA fact sheet, available at http://clu‐in.org/542F08009 , and includes background information on nanotechnology; its use in site remediation; issues related to fate, transport, and toxicity; and a discussion of performance and cost data for field tests. The site list is available at http://clu‐in.org/products/nanozvi . © 2008 Wiley Periodicals, Inc.     

Water movement through an experimental soil liner

A field-scale soil liner was constructed to test whether compacted soil barriers in cover and liner systems could be built to meet the U.S. EPA saturated hydraulic conductivity requirement (⩽ 1 × 10⁻⁷ cm s⁻¹). The 8 × 15 × 0.9 m liner was constructed in 15 cm compacted lifts using a 20,037 kg pad-foot compactor and standard engineering practices. Water infiltration into the liner has been monitored for one year. Monitoring will continue until water break through at the base of the liner occurs. Estimated saturated hydraulic conductivities were 2.5 × 10⁻⁹, 4.0 × 10⁻⁸, and 5.0 × 10⁻⁸ cm s⁻¹ based on measurements of water infiltration into the liner by large- and small-ring infiltrometers and a water balance analysis, respectively.Also investigated in this research was the variability of the liner's hydraulic properties and estimates of the transit times for water and tracers. Small variances exhibited by small-ring flux data suggested that the liner was homogeneous with respect to infiltration fluxes. The predictions of water and tracer breakthrough at the base of the liner ranged from 2.4–12.6 y, depending on the method of calculation and assumptions made. The liner appeared to be saturated to a depth between 18 and 33 cm at the end of the first year of monitoring. Transit time calculations cannot be verified yet, since breakthrough has not occurred. The work conducted so far indicates that compacted soil barriers can be constructed to meet the saturated hydraulic conductivity requirement established by the U.S. EPA.     

The active role of state laws in superfund cleanups

The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA or Superfund) did not ignore the fifty individual states when establishing responsibility, authority, and liability for cleaning up hazardous waste sites. Although CERCLA gives EPA the ultimate authority to select a remedy for a contaminated site, the law was drafted not only to allow for state activity without EPA, but also for significant state input when EPA is involved. The relationship between a state (and its environmental laws) and EPA can help decide the remedial and financial interests of any potentially responsible party (PRP). This article discusses the relevant CERCLA provisions, recent court decisions, and resolved and unresolved issues in federal-state Superfund involvement, and recommends several common-sense strategies for PRPs when working with a state in a Superfund cleanup.     

Solidification/stabilization for remediation of wood preserving sites: Treatment for dioxins,PCP, creosote,and metals

This article discusses the use of solidification/stabilization (S/S) to treat soils contaminated with organic and inorganic chemicals at wood preserving sites. Solidification is defined for this article as making a material into a freestanding solid. Stabilization is defined as making the contaminants of concern nonmobile as determined from a leaching test. S/S then combines both properties. For more information on S/S in general the reader should refer to other publications (Connors, J.R. [1990]). Chemical fixation and solidification of hazardous wastes. New York: Van Nostrand Reinhold; US Environmental Protection Agency. [1993a]. Engineering bulletin solidification/stabilization of organics and inorganics (EPA/540/S‐92/015); Wiles, C.C. [1989]. Solidification and stabilization technology. In H.M. Freeman [Ed.], Standard handbook of hazardous waste treatment and disposal. New York: McGraw Hill) as this article addresses only wood preserving sites and assumes basic knowledge of S/S processes. For a more general discussion of wood preserving sites and some other remedial options, the reader may wish to refer to a previous EPA publication (US Environmental Protection Agency. [1992a]. Contaminants and remedial options at wood preserving sites [EPA/600/R‐92/182]). This article includes data from the successful remediation of a site with mixed organic/inorganic contaminants, remediation of a site with organic contaminants, and detailed treatability study results from four sites for which successful formulations were developed. Included are pre‐ and post‐treatment soil characterization data, site vaines. ileizdot‐ names (in some cases), treatment formulas used (generic aridproprietary), costs, recommendations, and citatioiis to inore detailed refer‐ en ces. The data presen ted iiidica te that dioxins, pentachlorophepi 01 (PCP), creosote, polycyclic aromatic hydrocarbom (PAHsI, and metals can be treated at moderate cost by the use of S/S techuologp.     

Integrated bioremediation of soil and groundwater at a superfund site

The soil and two aquifers under an active lumber mill in Libby, Montana, had been contaminated from 1946 to 1969 by uncontrolled releases of creosote and pentachlorophenol (PCP). In 1983, because the contaminated surface soil and the shallower aquifer posed immediate risks to human health and the natural environment, the U.S. Environmental Protection Agency placed the site on its National Priorities List. Feasibility studies in 1987 and 1988 determined that in situ bioremediation would help clean up this aquifer and that biological treatment would help clean up the contaminated soils. This article outlines the studies that led to a 1988 EPA record of decision and details the EPA-approved remedial plan implemented starting in 1989; EPA estimates a total cost of about $15 million (in 1988 dollars). The plan involves extensive excavation and biological treatment of shallow contaminated soils in two lined and bermed land treatment units, extraction of heavily contaminated groundwater, an aboveground bioreactor treatment system, and injection of oxygenated water to the contaminant source area, as well as to other on-site areas affected by the shallower aquifer's contaminant plume.     

Incineration treatment of arsenic-contaminated soil

An incineration test program was conducted at the U.S. Environmental Protection Agency's Incineration Research Facility to evaluate the potential of incineration as a treatment option for contaminated soils at the Baird and McGuire Superfund site in Holbrook, Massachusetts. The purpose of these tests was to evaluate the incinerability of these soils in terms of the fate of arsenic and lead and the destruction of organic contaminants during the incineration process. The test program consisted of a series of bench-scale experiments with a muffle furnace and a series of incineration tests in a pilot-scale rotary kiln incinerator system. The study reported in this paper was funded by the Environmental Protection Agency under Contract 68–C9–0038 to Acurex Corporation. It has been subjected to the Agency's review and has been approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.     

Legacy PCB building remediation

Polychlorinated biphenyls (PCBs) came onto the scene as an environmental threat quickly after they were discovered in humans and wildlife by Jensen in 1966. By October 1970, it was reported that PCBs were “truly ubiquitous pollutants” as PCBs were found at detectable concentrations in environmental samples throughout the world. Before 1971, the U.S. Environmental Protection Agency (EPA) reported that 26% of PCBs sold were used in open‐end use applications, such as caulks, sealants, plasticizers, surface coatings, ink, adhesive, and carbonless paper. Processing and distribution of PCBs in commerce were largely banned in the U.S. after July 1979 with certain continued uses authorized by the EPA. While PCBs were banned a long time ago, the ban had no immediate tangible effect on the continued use of regulated levels of PCBs in buildings constructed before the bans were implemented. Legacy buildings with PCB‐containing building materials continue to represent potential sources of indoor air, dust, outdoor air, and soil contamination. Where PCBs are present in building materials, they have the potential to pose a risk to building occupants. Proper removal of PCB‐containing materials is a highly effective approach to abating the risk. The removal can range from targeting specific building PCB‐containing materials through demolition of the building. Engineering and administrative controls can also be useful tools when addressing the risks posed by PCB‐containing materials.     

Look at groundwater quality to set VOC cleanup levels

In 1981, the Arizona Department of Health Services (ADHS) discovered groundwater contamination by solvents and chromium at the Phoenix Goodyear Airport (PGA), just outside the city of Phoenix. ADHS and the U.S. EPA sampled the site for the next two years, finding that eighteen of their wells were contaminated with trichloroethene (TCE), six exceeding ADHS's action level of five micrograms per liter (μg/l). In 1983, the PGA site was added to the National Priorities List, and, in 1984, EPA began a $3 million remedial investigation, focusing on soils and groundwater. This article discusses how that investigation inspired the authors to develop a stream-lined evaluation method for PGA's volatile organic compounds (VOCs), the process for establishing VOC cleanup levels, and the $26 million of remediation work needed to be done at the site. The heart of this effort is a computer program called VLEACH, loosely standing for VOC-LEACHing, which anticipates the influence of VOCs on PGA's groundwater, even as remediation proceeds.     

Synthetic Media: A Promising New Treatment Technology for 1,4‐Dioxane

1,4‐Dioxane (14DX) is classified as a probable human carcinogen by the US Environmental Protection Agency (EPA), and it has toxic effects on the kidney and liver. EPA's Health Advisory Level (HAL) for 14DX is 0.35 micrograms per liter (μg/L). Accordingly, several states have lowered their drinking water advisory levels and site cleanup levels. The widespread occurrence of 14DX in contaminated groundwater has contributed to a growing demand for remediation services. Treating 14DX is a challenge due to its very low Henry's law constant, low sorption potential, and strong ether linkages. The primary solution for 14DX remediation has been various forms of advanced oxidation processes (AOP), namely pump and treat followed by ex situ treatment with catalyzed ultraviolet light oxidation or ozone‐peroxidation. Many of the available advanced oxidation systems are complex, requiring careful monitoring and maintenance to adjust for variable source water and operating conditions. Synthetic media is a relatively new 14DX treatment technology that overcomes many of the operating challenges faced by existing technologies. AMBERSORB? 560 (AMBERSORB) has recently demonstrated the effective removal of 14DX over a wide range of concentrations and operating conditions, including those created by in situ thermal remediation. Consistent and reliable treatment down to sub‐0.3 μg/L levels differentiates synthetic media technology from other 14DX treatment technologies. AMBERSORB provides a solution to the problem of “stranded capital” by offering a 14DX treatment system capable of meeting regulatory standards today and in the foreseeable future. © 2014 Wiley Periodicals, Inc.