Estimating Remediation and Contaminant Respiration Emissions for Alternatives Comparisons at Petroleum Spill Sites

Greenhouse gas emissions assessments for site cleanups typically quantify emissions associated with remediation and not those from contaminant biodegradation. Yet, at petroleum spill sites, these emissions can be significant, and some remedial actions can decrease this additional component of the environmental footprint. This article demonstrates an emissions assessment for a hypothetical site, using the following technologies as examples: excavation with disposal to a landfill, light nonaqueous‐phase liquid (LNAPL) recovery with and without recovered product recycling, passive bioventing, and monitored natural attenuation (MNA). While the emissions associated with remediation for LNAPL recovery are greater than the other considered alternatives, this technology is comparable to excavation when a credit associated with product recycling is counted. Passive bioventing, a green remedial alternative, has greater remedial emissions than MNA, but unlike MNA can decrease contaminant‐related emissions by converting subsurface methane to carbon dioxide. For the presented example, passive bioventing has the lowest total emissions of all technologies considered. This illustrates the value in estimating both remediation and contaminant respiration emissions for petroleum spill sites, so that the benefit of green remedial approaches can be quantified at the remedial alternatives selection stage rather than simply as best management practices. ©2015 Wiley Periodicals, Inc.     

Dose Assessment for Process Water Tunnels at Hanford Site

The RESRAD‐BUILD and RESRAD computer codes were used for dose assessment of the 105‐C Process Water Tunnels at the Hanford Site. The evaluation assessed three different exposure scenarios: recreational use, tunnel maintenance worker, and residential use. The recreationist and maintenance worker scenarios were evaluated by using RESRAD‐BUILD, a computer model for analyzing the radiological doses resulting from remediation and occupancy of structures contaminated with radioactive material. The recreationist was assumed to use the tunnels as an overnight shelter for eight hours per day for one week. The maintenance worker was assumed to spend 20 hours per year working in the the tunnel. Six exposure pathways were considered for both scenarios in dose assessment. The gradual removal of surface contamination over time and ingrowth of decay products were considered in calculating the dose at different times. The maximum dose would occur immediately after the release and was estimated to be 1.9 mrem/yr for the recreationist and 0.9 mrem/yr for the maintenance worker. The residential scenario was evaluated by using the probabilistic RESRAD code. It was assumed that total activity from the tunnels would be brought into the near‐surface layer by future human activities. Eight exposure pathways were considered. The maximum yearly dose for this very unlikely scenario would occur immediately after the release and was less than 4 mrem/yr for the maximally exposed individual. The assessment demonstrates that both codes are suitable for nuclear facility decontamination and decommissioning sites, where buildings and structures with residual radioactivity must be evaluated to facilitate property transfer or release.     

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.     

Simulations of Atmospheric Dispersion Following a Spillage of Petroleum at Sea

In January 1997 7000 t of refined petrol were spilled into the English Channel following a collision in dense fog off Ostend. The following day reports of petrol odours were recorded throughout central England at distances up to 300 km from the spill site. One possibility is that mass hysteria was induced by media reports of the accident coupled with the publicised wind direction. Indeed, the simulated gas cloud trajectory does not pass over central England if the petrol is assumed to have evaporated over a period of about 3 h. However, a feasible advection path can be reproduced by assuming that the water/atmosphere exchange of vapours occurred on a time scale of 12 h, the extended evaporation being due to the formation of subsurface droplets by wave action. Evidence to support the simulated trajectory has been obtained from the UK National Air Quality Information Archive which contains hourly data for benzene and NO_x concentrations. By regressing the benzene concentration against NO_x which is assumed to be an indicator of traffic density, it is shown that an increase in benzene concentrations on the day following the spillage was consistent with the simulated movement of the vapour cloud.     

Ozone Deposition at a Forest Site in NE Bavaria

The dry deposition of ozone to aconiferous forest in northeastern Bavaria(southern Germany) was quantified during 1999with both the eddy correlation method and a bigleaf model. The model included parameterizationsof the atmospheric transfer resistances fromdirect measurements, stomatal resistance from aplant ecological model, and an estimation of thecuticle resistance as function of leaf wetness.Early in the season, the measured and themodelled deposition fluxes were in goodagreement, although the modelled fluxes tended tounderestimate the measured ones. Thisunderestimation was more pronounced in the latesummer, when high nocturnal fluxes werefrequently measured. The model parameterizationof the cuticle and the stomatal resistances didnot allow for such high fluxes. In these cases,the 24 hour average of the measured fluxes wereup to 4.5 times higher than the modelled ones.The reasons for these large discrepancies remainunknown. However, assigning the unaccounted partof the deposition to a nonstomatal surfacedeposition pathway, a new parameterization of therespective resistance yielded an average value of300 s m^-1. It exhibited a decreasing trendthrough the vegetation period.     

Rethinking groundwater monitoring at the Hanford Site

Groundwater monitoring at Department of Energy's (DOE's) Hanford Site is a large, expensive undertaking serving multiple purposes, including compliance with regulations and DOE orders, remediation efforts under CERCLA, and sitewide risk evaluations. Like most large Federal facilities, the monitoring program currently in place has evolved and grown overtime as new requirements were established and groups were assigned to address them. DOE and its regulators simultaneously awakened to the fact that there was a need to reevaluate the monitoring activities at Hanford, to better integrate the program, to avoid duplicative sampling, to improve everyone's understanding of the performance of the network, and to evaluate whether adequate data could be collected for lower cost. This paper describes the approch that was developed to guide the rethinking effort with direct and extensive involvement of DOE, EPA, Washington Department of Ecology, Indian Tribes, and DOE Contractors, and how this approach was applied to a large portion of the site. Both the human element of the process (cultural change), as well as some of the technical details associated with the effort, including a flexible application of EPA's data quality objectives process, are discussed.     

Field Performance of Point Velocity Probes at a Tidally Influenced Site

Conventional methods to estimate groundwater velocity that rely on Darcy's Law and average hydrogeologic parameter values are insensitive to local‐scale heterogeneities and anisotropy that control advective flow velocity and direction. Furthermore, at sites that are tidally influenced or have extraction wells with variable pumping schedules, infrequent water‐level measurements may not adequately characterize the range and significance of transient hydraulic conditions. The point velocity probe (PVP) is a recently developed instrument capable of directly measuring local‐scale groundwater flow velocity and direction. In particular, PVPs may offer distinct advantages for sites with complex groundwater–surface water interactions and/or with spatially and temporally variable groundwater flow conditions. The PVP utilizes a small volume of saline tracer and inexpensive sensors to directly measure groundwater flow direction and velocity in situ at the centimeter‐scale and discrete times. The probes are installed in conventional direct‐push borings, rather than in wells, thus minimizing the changes and biases in the local flow field caused by well installation and construction. Six PVPs were installed at a tidally influenced site in North Carolina to evaluate their implementability, performance, and potential value as a new site characterization tool. For this study, a new PVP prototype was developed using a rapid prototyping machine (i.e., a “three‐dimensional printer'') and included both horizontally and vertically oriented tracer detectors. A site‐specific testing protocol was developed to account for the spatially and temporally variable hydraulic conditions and groundwater salinity. The PVPs were tested multiple times, and the results were compared to the results of several different groundwater flux and velocity estimation tools and methods, including a heat‐pulse flowmeter, passive flux meters, single‐well tracer tests, and high‐resolution hydraulic gradient analysis. Overall, the results confirmed that the PVP concept is valid and demonstrated that reliable estimates of groundwater velocity and direction can be obtained in simple settings. Also, PVPs can be successfully installed by conventional methods at sites where the formation consists primarily of noncohesive soils and the water table is relatively shallow. Although some PVP tests yielded consistent and reliable results, several tests did not. This is likely due to the highly transient flow conditions and limitations associated with the PVP design and testing procedures. PVPs offer particular advantages over, and can effectively complement, other groundwater flow characterization techniques for certain conditions, and objectives may be useful for characterizing complex flow patterns under steady conditions; however, this study suggests that PVPs are best suited for conditions where the flow hydraulics are not highly transient. For sites where the hydraulic conditions are highly transient, the most reliable approach for understanding groundwater flow behavior and groundwater–surface water interactions would generally involve both a high‐resolution hydraulic gradient analysis and another local‐scale method, such as tracer testing. This study also highlighted some aspects of the current PVP design and testing protocol that can be improved upon, including a more robust connection between the PVP and injection line and further assessment of tracer solution density effects on vertical flow. © 2013 Wiley Periodicals, Inc.     

化学氧化法脱除石油焦中的硫

分别采用硝酸、硝酸-冰醋酸混合液以及王水作氧化剂脱除石油焦中的硫。实验结果表明:石油焦粒径越小,脱硫率越高;随液固比(氧化剂体积与石油焦质量比,mL/g)增大、反应时间延长、反应温度升高,脱硫率先增大,达到极值后保持稳定。王水的脱硫率高于硝酸和硝酸-冰醋酸混合液。王水脱除石油焦中硫的最佳工艺条件为:石油焦粒径0.1mm,液固比20mL/g,反应时间20h,反应温度50℃。在此最佳条件下,脱硫率达42.3%。经王水在最佳脱硫工艺条件下处理后,可有效脱除石油焦中大部分的噻吩类和硫醇类有机硫以及全部的无机硫。     

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.     

电化学法处理高盐苯酚废水的研究

对在氯盐电解质中用电化学方法处理含酚废水进行了研究，着重探讨了盐的种类与浓度、反应温度与溶液：pH、电流密度、苯酚初始浓度及阴阳极转换频率对苯酚去除率的影响。在Na2SO4的浓度为0．2mol／L，NaCl的浓度为0．1mol／L、苯酚初始质量浓度为200mg／L、电流密度为0．04A／cm^2、温度为35℃、pH为12．5、阴阳极转换频率为5min/次及反应时间为200min的条件下，苯酚的去除率为99．5％，COD去除率为5％，CIO^-把苯酚氧化成了其他有机化合物。     

Computer Modeling of Oil Spill Trajectories With a High Accuracy Method

This paper proposes a high accuracy numerical method to model oil spill trajectories using a particle-tracking algorithm. The Euler method, used to calculate oil trajectories, can give adequate solutions in most open ocean applications. However, this method may not predict accurate particle trajectories in certain highly non-uniform velocity fields near coastal zones or in river problems. Simple numerical experiments show that the Euler method may also introduce artificial numerical dispersion that could lead to overestimation of spill areas. This article proposes a fourth-order Runge–Kutta method with fourth-order velocity interpolation to calculate oil trajectories that minimize these problems. The algorithm is implemented in the OilTrack model to predict oil trajectories following the “Nissos Amorgos” oil spill accident that occurred in the Gulf of Venezuela in 1997. Despite lack of adequate field information, model results compare well with observations in the impacted area.     

电化学工艺处理有机废水的研究进展

综述了目前国内外学者在二维电极和三维电极的开发和改进方面的研究成果,指出了电化学氧化技术和电极材料的主要研究方向和发展趋势.提出为解决电化学水处理技术中提高电催化效率和延长电极寿命的问题,当前研究的主要方向应集中在阳极材料、反应器结构和处理工艺方面.     

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.     

In Situ Solidification (ISS) of River Sediments: Pilot Demonstration and Discussion of ISS as a Remedial Alternative to Dredging and Capping

In situ solidification (ISS) is a proven technology for remediation of upland site soils, but has not been thoroughly demonstrated for use in impacted underwater sediments. This article describes the first successful use of ISS techniques to solidify underwater sediments containing manufactured gas plant non‐aqueous‐phase liquid (NAPL). The techniques consisted of mixing cementitious grout with the sediments in situ to create a monolith that immobilized the contaminants, significantly decreased the hydraulic conductivity, and also vastly decreased contaminant leaching potential of the sediments. The success of this pilot demonstration project suggests that ISS may be a viable alternative for: sites requiring deep dredging; large volume projects on urban waterways where staging and amending areas are limited; sites with NAPL impacts that cannot be controlled during dredging; and sites where eventual NAPL breakthrough is anticipated if reactive caps are employed. The potential economic, environmental, and operational benefits of this technology will be discussed. This article focuses on the primary objectives of the pilot demonstration: to meet quantitative performance criteria for strength and hydraulic conductivity; to assess the leach performance of the solidified sediments; and to satisfy water quality parameters for turbidity, pH, and sheen. Approach/activities: The pilot study utilized a customized marine platform (modular floats, tug boats, etc.) and full‐scale ISS equipment (auger rig, silos, etc.) and varied operational parameters to provide a range of data to assist in evaluating the feasibility and efficacy of the technology for use in similar environments and in planning future ISS projects on the water. Water quality controls and monitoring were implemented during the operation, and the study documented and evaluated the environmental disruption (short‐term impacts) and costs of the application of the ISS process to contaminated aquatic sediments. ©2016 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.     

Second Phase Evaluation of a Protocol for Testing a Fire Resistant Oil Spill Containment Boom

Most response plans for in situ burning of oil at sea call for the use of a fire-resistant boom to contain the oil during a burn. Presently, there is no standard method for the user of fire-resistant boom to evaluate the anticipated performance of different booms. The American Standard for Testing Materials (ASTM) F-20 Committee has developed a draft standard, `Standard Guide for in situ Burning of Oil Spills on Water: Fire-Resistant Containment Boom'; however, the draft provides only general guidelines and does not specify the details of the test procedure. Utilizing the guidelines in the draft standard, a second series of experiments was conducted to evaluate a protocol for testing the ability of fire-resistant booms to withstand both fire and waves.     

The Social and Political Meaning of the Exxon Valdez Oil Spill

In this paper we argue that the Exxon Valdez oil spill gained so much attention because of its setting in Alaska. Alaska symbolizes for many Americans the wilderness or frontier that has long been part of American thought. At the same time, American national development has largely depended on the discovery and use of the nation’s abundant natural resources. The setting of the Valdez spill in the seemingly pristine waters of Prince William Sound brought the tension between our national identification with wilderness and our national need for further natural resource exploitation into sharp focus. In the aftermath of the spill, a legislative deadlock was passed and the Oil Pollution Act of 1990 was passed. The Valdez accident had longer-term consequences as well, most prominent of which is related to the ongoing debate over whether to open up the coastal plain in the Arctic National Wildlife Refuge to further development.     

超声波协同电化学氧化降解苯胺的研究

采用超声波协同电化学氧化法处理苯胺溶液，考察了超声时间、苯胺浓度、溶液pH、电解电压、电解质浓度等因素对苯胺降解率的影响。试验结果表明：在超声波与电化学联合作用下，苯胺降解率随降解时间的延长而提高，苯胺浓度无论是低还是高，声电联合作用完全去除苯胺只需30min左右，电化学单独作用完全去除苯胺约需要120min；苯胺初始浓度较低时，其降解率较高；随着pH的增大，苯胺降解率先降低后提高，pH为10左右苯胺降解率最高；电解质Na2SO4的浓度对苯胺降解率影响不大；电解电压在4～12V范围内，苯胺降解率随电压升高而提高，电压为16V时，其降解率下降。     

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.