Long‐Term Contaminant Trends at the Picillo Farm Superfund Site in Rhode Island

Environmental disasters, such as the infamous Love Canal site or the Valley of Drums, have taken many years and consumed billions of dollars to investigate and remediate. In consequence, a large amount of geologic and hydrologic information has been gathered over the past few decades. Because of the difficulties involved with compiling this information, scientists and professionals rarely use the data to investigate the unique long‐term databases. This article presents for the first time the compilation of chemical fate and transport data from the Picillo Farm Superfund site in Rhode Island. The data cover a quarter of a century worth of geologic, hydrogeologic, and geochemical information and indicate significant changes in the contaminant inventory and the center of mass contaminant location over time. Many of these changes would have been missed if a data set of shorter duration were evaluated. Thus, compiling and evaluating data collected over many years can be extremely valuable in understanding the fate and transport of contaminants and determining the effectiveness of remediation. © 2002 Wiley Periodicals, Inc.     

Case Study and Retrospective: Aerobic Fixed Film Biological Treatment Process for 1,4‐Dioxane at the Lowry Landfill Superfund Site

An aerobic fixed film biological treatment system has been successfully treating recovered groundwater/landfill leachate containing 1,4‐dioxane, tetrahydrofuran (THF), and other constituents since 2003. The most likely mode of 1,4‐dioxane biotransformation is via a cometabolic pathway in the presence of THF. Pilot studies conducted during the process development phase established a design basis process loading factor of 0.6 g 1,4‐dioxane and THF (as chemical oxygen demand [COD])/g total solids per day and proved the efficacy of the process. Full‐scale design includes the use of three parallel moving bed bioreactors with effluent recycle capability. Removal efficiencies in excess of 98 percent have been documented for 1,4‐dioxane. Evolving operational challenges are associated with recent trends in 1,4‐dioxane pretreatment discharge limitations in combination with ongoing process optimization and increased influent flow rate conditions associated with seasonal precipitation patterns. ©2016 Wiley Periodicals, Inc.     

Application of In-Situ Vitrification at the Parsons Chemical Site

This article presents the results of demonstration of Geosafe Corporation's in-situ vitrification (ISV) technology at the Parsons Chemical/ETM Enterprises Superfund site in Grand Ledge, Michigan. The primary focus of this article is on the EPA's Superfund Innovative Technology Evaluation (SITE) Program assessment of the sixth melt. A total of eight melts were performed during this project. This demonstration was part of the SITE Program Demonstration (USEPA, 1994), which helped develop innovative hazardous waste treatment technologies, especially those offering permanent remedies for contaminated Superfund and other hazardous waste sites. The demonstration results are not only applicable to this particular project, but are also indicative of other Geosafe project experiences and demonstrate the current state of the ISV technology. The demonstration included two phases. In the first phase, the ISV technology was used to treat the Parsons contaminated soil. In the second phase, post-testing and analysis were conducted about one year after the ISV technology was applied to confirm that the vitrification was completed and that no contamination migration had occurred.     

Evaluation of natural attenuation at a 1,4‐dioxane‐contaminated site

1,4‐Dioxane entered the environment as a result of historic leaks and spills in the production area at an industrial facility in the southeastern coastal plain. The areal extent of the 1,4‐dioxane plume is several hundred acres and is largely contained on the site. Land use adjacent to the plant property is primarily undeveloped (wetlands or woods) or industrial, with a small area of mixed land use (commercial/residential) to the southwest and north. The surficial aquifer is a relatively simple hydrogeologic system with well‐defined boundaries and is comprised of a 50‐ to 70‐foot‐thick deposit of alluvial/fluvial sand and gravel that overlies an aquitard in excess of 100 feet thick. A groundwater flow model, developed and calibrated using field‐measured data, was used for the fate‐and‐transport modeling of 1,4‐dioxane. The flow‐and‐transport model, combined with the evaluation of other site geochemical data, was used to support the selection of monitored natural attenuation (MNA) as the proposed groundwater remedy for the site. Since the active sources of contamination have been removed and the modeling/field data demonstrated that the plume was stable and not expanding, the proposed MNA approach was accepted and approved by the regulatory agency for implementation in 2004. Subsequent accumulated data confirm that concentrations in the 1,4‐dioxane plume are declining as predicted by the fate‐and‐transport modeling. © 2008 Wiley Periodicals, Inc.     

Results of a field study—Sampling with ISOCS and SAM 935 at the Savannah River Site

This article focuses on the results of a delineation of radioactive contaminants using expedited field characterization equipment at the Department of Energy's Savannah River Site in South Carolina. The objective of the study was to delineate a potential contamination area in the TNX Inner Swamp using cost‐effective field sampling equipment that would give results in a timely manner. The expedited field characterization equipment used was the In Situ Object Counting System (ISOCS) and the Model 935 Surveillance and Measurement System (SAM 935). The study involved an area of approximately 200 acres with 89 surveyed locations. Originally, the contaminant of concern was thorium‐232 because of the health risk to future on‐site workers. As the fieldwork progressed, there were no exceedances in thorium‐232 activities; however, there was one slight exceedance of uranium‐238. The delineation was established from using the ISOCS and SAM 935 sampling equipment in addition to soil sampling from the 0‐ to 1‐foot interval. There was a strong correlation in the analytical data from both the ISOCS and SAM 935 measurements. Thus, this type of sampling characterization is beneficial for determining the extent of contamination at hazardous waste sites. © 2006 Wiley Periodicals, Inc.     

VOC气体检测仪在进口废塑料检验中的应用

针对挥发性有机化合物(VOC)气体在现实中的危害,对废物原料检验的标准进行了探讨,对废物原料检验中如何进行VOC检测进行分析并提出建议。     

The Use of Zero‐Valent Iron (ZVI) Technology to Promote DDT and Dieldrin Degradation at Point Pelee National Park

Point Pelee National Park (PPNP) is highly contaminated with dichlorodiphenyltrichloroethane (DDT) and dieldrin due to the historical use of these two persistent organochlorine pesticides. Zero‐valent iron (ZVI) technology with and without amendments has been successfully used in the past to promote organochlorine pesticides degradation in several locations in North America and Europe. In this study, the use of two commercially available ZVI products, DARAMEND^® and EHC^®, to promote DDT and dieldrin degradation in PPNP's soil and groundwater were investigated. DARAMEND^® was applied to PPNP's soil in a laboratory experiment and in an in situ pilot‐scale plot. In both cases, DARAMEND^® did not significantly increase DDT or dieldrin degradation in treated soils. The effectiveness of EHC^® was tested in a laboratory experiment that simulated the park's groundwater environment using PPNP's pesticide contaminated soil. The result was consistent with the one reported for DARAMEND^®, in that there was no significant increase in DDT or dieldrin degradation in any of the samples treated with EHC^®. These results demonstrate that both of these ZVI commercially available products are not suitable for in situ remediation at PPNP.  ©2017 Wiley Periodicals, Inc.     

Pilot Scale Demonstration of the Electrochemical Peroxidation Process at a Petroleum Spill Site

In a pilot test experiment involving approximately 200,000 gallons of groundwater, Electrochemical Peroxidation (ECP) was used to degrade aqueous phase volatile organic compounds (VOCs) including benzene, toluene, ethylbenzene, and xylene (BTEX) compounds and methyl tertbutyl ether (MTBE) from a petroleum spill. ECP involves a form of the Fenton's Reagent reaction, which uses electrochemically generated iron and dilute hydrogen peroxide (<30 mg/L) to break down organic molecules through oxidation to carbon dioxide and water. This article discusses a pilot scale demonstration of the ECP technology and its application to aqueous phase organic contaminants. The remedial approach used at the pilot test site involves three phases: (1) ex‐situ chemical oxidation, (2) in‐situ oxidation by reinjection of treated effluent near the plume origin, and (3) reestablishment of aerobic biodegradation as the residual hydrogen peroxide discharged to a series of upgradient wells degrades to oxygen. Analytical results of the pilot demonstration indicate that the ex‐situ chemical oxidation reduced total BTEX concentrations in groundwater from over 1,000 ppb to undetectable concentrations (<1 ppb). © 2000 John Wiley & Sons, Inc.     

Before‐after control‐impact paired modeling of groundwater bentazon treatment at a phytoremediation site

A Before‐ After Control‐ Impact Paired (BACIP) model was used to evaluate the effectiveness of phytoremediation treatment on reduction of bentazon concentrations in shallow groundwater at a study site in Louisiana. Two different statistical approaches were made to evaluate the impact to this test site from the remediation program through time. Data were evaluated by Bayesian analysis of variance test methods. Data sets were unique in that the control data used for impact evaluation, as compared to before and after data, were compiled from groundwater upgradient monitoring wells existing prior to remediation. The statistical model supports the hypothesis that the phytoremediation program has positively impacted groundwater at the study site. © 2006 Wiley Periodicals, Inc.     

Demonstration of MicroBlower™ technology for sustainable soil vapor extraction: Case studies at the Savannah River Site,South Carolina

The MicroBlower Sustainable Soil Vapor Extraction System is a cost‐effective device specifically designed for remediation of organic compounds in the vadose zone. The system is applicable for remediating sites with low levels of contamination and for transitioning sites from active source technologies such as active soil vapor extraction to natural attenuation. It can also be a better choice for remediating small source zones that are often found in “tight zones” that are controlled by diffusion rate. The MicroBlower was developed by the Savannah River National Laboratory at the US Department of Energy's Savannah River Site to address residual volatile organic compound (VOC) contamination after shutdown of active soil vapor extraction systems. In addition, the system has been deployed to control recalcitrant sources that are controlled by diffusion rates. © 2012 Wiley Periodicals, Inc.     

The use of enhanced bioremediation at the Savannah River Site to remediate pesticides and PCBs

Enhanced bioremediation is quickly developing into an economical and viable technology for the remediation of contaminated soils. Until recently, chlorinated organic compounds have proven difficult to bioremediate. Environmentally recalcitrant compounds, such as polychlorinated biphenyls (PCBs) and persistent organic pesticides (POPs) such as dichlorodiphenyl trichloroethane (DDT) have shown to be especially arduous to bioremediate. Recent advances in field‐scale bioremedial applications have indicated that biodegradation of these compounds may be possible. Engineers and scientists at the Savannah River Site (SRS), a major DOE installation near Aiken, South Carolina, are using enhanced bioremediation to remediate soils contaminated with pesticides (DDT and its metabolites, heptachlor epoxide, dieldrin, and endrin) and PCBs. This article reviews the ongoing remediation occurring at the Chemicals, Metals, and Pesticides (CMP) Pits using windrow turners to facilitate microbial degradation of certain pesticides and PCBs. © 2003 Wiley Periodicals, Inc.     

ERI evaluation of injectates used at a dry‐cleaning site

A former dry‐cleaning site in Jackson, Tennessee, has undergone remediation to treat dense nonaqueous‐phase liquid (trichloroethene [TCE] and tetrachloroethene [PCE]) contamination in the subsurface. The dry cleaning operation closed in 1977. In 2002, a series of injections were made at the site consisting of corn syrup, vegetable oils, and Simple Green®. In 2004, approximately 200 cubic yards of contaminated soil were excavated, and the bottom of the excavation was covered with sodium lactate. In 2009, the site was characterized using proprietary electrical resistivity imaging (ERI; commercially available as Aestus GeoTrax Surveys^TM). Follow‐up confirmation soil borings targeted anomalies detected via the geophysical work. The results indicate an extremely electrically conductive (less than 1 ohm‐m) vadose zone downgradient from the injection wells, and extremely electrically resistive areas (greater than 10,000 ohm‐m) in the phreatic zone near the injection area. The sample data indicate that the electrically resistive anomalous zones contain moderate to high concentrations of undegraded dry‐cleaning compounds. Electrically conductive anomalous zones are interpreted to be areas of biological activity generated by the amendments injected into the subsurface based on the extreme conductivity values detected, the chemical composition (i.e., PCE degradates are present), and the dominant vadose‐zone location of the conductive zones. © 2012 Wiley Periodicals, Inc.     

A “convective” flow biofilter for the biofiltration of contaminants at sub‐low concentrations

Biofiltration of contaminants at concentrations below a certain level (sub‐low concentrations) is not as effective as at higher concentrations, which leads to incomplete removal of the contaminants, because of diffusive mass transfer of the contaminants inside the biofilm and insufficient carbon and energy sources to sustain biomass growth and maintenance. To overcome the limitation of diffusion, this article proposes the concept of convective flow biofilm in which contaminated air flows through the porous biofilm and thus carries the carbon and energy sources to the biomass. The innovative concept of convective flow biofilm was implemented in a convective flow biofilter (CFB), which was built from activated carbon‐coated ceramic monoliths by selectively blocking the channel openings. The CFB was tested for 11 weeks for the biofiltration of toluene at inlet concentrations below 100 ppmv. The CFB performed consistently better than the conventional diffusive flow biofilter (DFB), as indicated by the higher removal efficiencies and the higher CO₂ productions. The CFB demonstrated up to 30 percent higher removal efficiency and an up to 100 percent higher elimination capacity than the DFB. © 2007 Wiley Periodicals, Inc.     

Rapid full‐scale bioremediation of perchlorate in soil at a large brownfields site

The former Bermite site north of Los Angeles, California, was used to manufacture various explosives and related products containing energetic compounds, including perchlorate. Remediation of perchlorate in site soil and groundwater is being conducted to meet regulatory requirements and allow planned redevelopment activities to proceed. The general approach to perchlorate remediation of shallow soil at the site includes excavation of affected soils followed by ex situ bioremediation. Glycerin was chosen for use as an electron donor because of its stability, safety, low cost, and regulatory acceptance. However, full‐scale bioremediation operation with glycerin initially resulted in inconsistent results despite consistent perchlorate biodegradation observed in treatability study microcosms. To eliminate the inconsistency and optimize the biotreatment process, additional studies were performed in the field on parallel tracks to determine crucial factor(s) that influenced inconsistent breakdown of perchlorate in site soils. Total Kjeldahl nitrogen (TKN) was determined to be a significant factor limiting perchlorate biodegradation. The addition of di‐ammonium phosphate (DAP) resulted in the consistent and complete perchlorate removal, generally within two weeks of incubation with a median destruction rate of about 200 μg/kg/day. Soil processing rates were gradually increased over the year, and, by the summer, approximately 2,000 to 2,500 tons of soil were being processed per day with a total of approximately 160,000 tons processed by the end of July. The total unit treatment cost for the process is about approximately $35/ton. The glycerin‐DAP process is playing a major role in the remediation of this 1,000‐acre former industrial site. © 2008 Wiley Periodicals, Inc.     

Unreliability of co‐occurrence‐based sediment quality guidelines for contaminated sediment evaluations at Superfund/hazardous chemical sites

Many Superfund/hazardous chemical sites include waterbodies whose sediments contain hazardous chemicals. With the need to assess, rank, and remediate contaminated sediments at such sites, as well as in other waterways, regulators seek a simple, quantitative assessment approach that feeds easily into a decision‐making scheme. Numeric, co‐occurrence‐based “sediment quality guidelines” have emerged with the appearance of administrative simplicity. However, the very foundation of the co‐occurrence approach, based on the total concentrations of a chemical(s) in sediment, is technically invalid; its application relies on additional technically invalid presumptions. Use of technically invalid evaluation approaches renders any assessment of the significance of sediment contamination unreliable. This article reviews the technical roots and assumptions of the co‐occurrence‐based SQGs, the fundamental flaws in the rationale behind their development and application, and their misapplication for sediment quality evaluation. It also reviews concepts and approaches for the more reliable evaluation, ranking, and cleanup assessment of contaminated sediments at Superfund sites and elsewhere. © 2005 Wiley Periodicals, Inc.     

Pilot‐scale demonstration of in situ capping of PCB‐containing sediments in the lower Grasse River

A fish‐consumption advisory is currently in effect in a seven‐mile stretch of the Grasse River in Massena, New York, due to elevated levels of PCBs in fish tissue. One remedial approach that is being evaluated to reduce the PCB levels in fish from the river is in situ capping. An in‐river pilot study was conducted in the summer of 2001 to assess the feasibility of capping PCB‐containing sediments of the river. The study consisted of the construction of a subaqueous cap in a seven‐acre portion of the river using various combinations of capping materials and placement techniques. Optimal results were achieved with a 1:1 sand/topsoil mix released from a clamshell bucket either just above or several feet below the water surface. A longer‐term monitoring program of the capped area commenced in 2002. Results of this monitoring indicated: 1) the in‐place cap has remained intact since installation; 2) no evidence of PCB migration into and through the cap; 3) groundwater advection through the cap is not an important PCB transport mechanism; and 4) macroinvertebrate colonization of the in‐place cap is continuing. Additional follow‐up monitoring in the spring of 2003 indicated that a significant portion of the cap and, in some cases, the underlying sediments had been disturbed in the period following the conclusion of the 2002 monitoring work. An analysis of river conditions in the spring of 2003 indicated that a significant ice jam had formed in the river directly over the capping pilot study area, and that the resulting increase in river velocities and turbulence in the area resulted in the movement of both cap materials and the underlying sediments. The pilot cap was not designed to address ice jam–related forces on the cap, as the occurrence of ice jams in this section of the river had not been known prior to the observations conducted in the spring of 2003. These findings will preclude implementation of the longer‐term monitoring program that had been envisioned for the pilot study. The data collected immediately after cap construction in 2001 and through the first year of monitoring in 2002 serve as the basis for the conclusions presented in this article. It should be recognized that, based on the observation made in the spring of 2003, some of these conclusions are no longer valid for the pilot study area.The occurrence of ice jams in the lower Grasse River and their importance on sediments and PCBs within the system are currently under investigation. © 2003 Wiley Periodicals, Inc.     

Geochemical evaluation of metals in groundwater at long‐term monitoring sites and active remediation sites

At many sites, long‐term monitoring (LTM) programs include metals as chemicals of concern, although they may not be site‐related contaminants and their detected concentrations may be natural. At other sites, active remediation of organic contaminants in groundwater results in changes to local geochemical conditions that affect metal concentrations. Metals should be carefully considered at both types of sites, even if they are not primary contaminants of concern. Geochemical evaluation can be performed at LTM sites to determine if the monitored metals reflect naturally high background and, hence, can be removed from the analytical program. Geochemical evaluation can also be performed pre‐ and post‐treatment at active remediation sites to document the effects of organics remediation on metals and identify the processes controlling metal concentrations. Examples from both types of sites are presented in this article. © 2008 Wiley Periodicals, Inc.     

The Use of Natural Systems to Remediate Groundwater: Department of Energy Experience at the Savannah River Site

Natural remediation is moving toward the forefront as engineers clean groundwater at the Savannah River Site (SRS), a major Department of Energy (DOE) installation near Aiken, South Carolina. This article reviews two successful, innovative remediation methods currently being deployed: biosparging to treat chlorinated solvents and phytoremediation to address tritium in groundwater. The biosparging system reintroduces oxygen into the groundwater and injects nutrient compounds for in‐situ remediation. The system has greatly reduced the concentrations of trichloroethylene (TCE) and vinyl chloride in wells downgradient from a sanitary landfill (SLF). Phytoremediation is an emerging technology that promises effective and inexpensive cleanup of certain hazardous wastes. Using natural processes, plants can break down, trap and hold, or transpire contaminants. This article discusses the use of phytoremediation to reduce the discharge of tritium to an on‐site stream at SRS. © 2002 Wiley Periodicals Inc. *