bluuebunny/crossref_metadata_2025 huggingface dataset:
An approximation to the likelihood function with application to environmental data
Authors: El‐Shaarawi A. H. , Naderi A.
Published: February 2007

The likelihood function for the location and scale family of distributions is approximated so that closed form estimates for the location and scale parameters can be obtained. The results are then extended to the particular case oft‐distributions with unknown degrees of freedom. The data are transformed so that the transformed data nearly follow a location and scale family of thet‐distribution. Simulation studies are done to examine the performance of the estimators and an application using data on the concentrations of α‐BHC in the Niagara River is presented.
A network design criterion for estimating selected attributes of the semivariogram
Authors: Zimmerman Dale L. , Homer Kenneth E.
Published: February 2007

The semivariogram plays a central role in a geostatistical analysis of spatially correlated environmental data. A valid semivariogram model is selected, and the parameters of that model are estimated, before kriging (spatial prediction) of environmental variables is performed. These inference procedures are generally based upon examination of the empirical semivariogram, which consists of average squared differences of data taken at sites lagged the same distance apart in the same direction. In some situations, the investigator may wish to estimate some attributes of the semivariogram more precisely than others. The efficient estimation of such attributes is affected significantly by the spatial configuration of the network of sites where measurements are taken. In this paper, an approach to network design is proposed that emphasizes the utility of the network for estimating selected attributes of the semivariogram. Details are given as to how the approach can be applied to precisely estimate (a) the ratio of nugget effect to sill, (b) a set of compatibility‐determining attributes, and (c) a geometric anisotropy. Acid deposition data taken from a sampling network in the eastern United States are used to further illustrate the approach.
Process understanding of a wastewater batch reactor with block‐wise PLS
Authors: Aguado D. , Zarzo M. , Seco A. , Ferrer A.
Published: January 2007

In this work a systematic methodology ‘block‐wise PLS’ has been applied to thoroughly analyse data from a sequencing batch reactor (SBR) operated for biological phosphorus removal from wastewater. The aim of this study was to diagnose process variables (collected by the inexpensive and low‐maintenance sensors installed in the SBR) likely related to the main key indicator of process performance: the phosphorus removal efficiency (PRE), determined off‐line in the quality control laboratory. In this way, it is intended to aid the process operators in the detection of abnormal values of these critical variables which would indicate undesirable process performance, so that, they could act on the process to avoid the negative consequences of the disturbance as soon as possible. The results of this research clearly show that the applied methodology can be considered as an effective tool to diagnose the process and can contribute to achieve a better process understanding as well as to optimise the process. Copyright © 2007 John Wiley & Sons, Ltd.
Environmental review strategy for R&D activities
Authors: Rice Steven C.
Published: February 2007

An organized environmental review strategy can assist an R&D facility or organization in ensuring that their activities not only comply with applicable site and operational requirements, but also address and resolve environmental issues and costs during the process development phase of their work. It is at this stage of R&D where efforts toward minimizing generation of hazardous waste and reducing “end‐of‐the‐pipe” control in potential commercial applications can be most effective. This article presents and describes five basic concepts which, when combined, can create a strong, purposeful environmental review program. Exxon Research and Engineering Company's review process is described as a specific example.
An evaluation of fine particle wet scrubbers
Authors: Blackwood T. R.
Published: February 2007

A study was undertaken to reduce emissions from a calciner stack. Tests were conducted to characterize the particle size distribution, effluent loading, and chemical composition. Several methods for reducing emissions were evaluated. The source of the effluent was found to be due to some combination of: excessive mist carryover from a spraytower, flashing of high solids concentration quench liquid, poor flow patterns, a large quantity of fine particles, condensation of metal vapors, or gas phase reaction which formed fine particles. A series of studies were conducted to improve the operation of the spray tower. As only limited success was achieved with these methods several other control devices were evaluated. This article discusses (1) the methodology used to evaluate the cause of the effluent problem, (2) the principles followed in obtaining a representative slipstream, and (3) the performance of the three devices tested, along with parameters which affect performance.
Important issues related to air pollution at municipal solid waste facilities
Authors: Savage G. M. , Bordson D. L. , Diaz L. F.
Published: February 2007

This paper presents a discussion of municipal solid waste (MSW) combustion and emission control. The issues of combustion technology, of available air pollution control systems, and of public health are explored in order to present an overview of the state‐of‐the‐art of combustion and air pollution control at facilities that burn unprocessed MSW or processed forms such as refuse‐derived fuel (RDF). The discussion also includes a presentation of the results of a study sponsored by the Minnesota Pollution Control Agency (MPCA), and performed by Cal Recovery Systems, Inc. (CRS), for the purpose of assisting the MPCA in the development of performance and operating guidelines for MSW combustion facilities to be sited in Minnesota.
The evaporation times of drop distributions and their impact on costs of in‐duct humidification systems for retrofitting electrostatic precipitators
Authors: Weinstein Bruce
Published: February 2007

Retrofit flue gas desulfurization (FGD) systems for utility or industrial boilers installed upstream of an existing electrostatic precipitator (ESP) increase the solids loading and often the resistivity of the solids. These factors can increase the outlet emissions from the ESP. A humidification system installed upstream of the ESP is a cost effective means to restore the performance. The feasibility of installing a humidification system within the existing duct requires having an unobstructed straight section with adequate residence time so that the water drops can completely evaporate. Failure to achieve complete evaporation can lead to the formation of cementations solids. A method is provided to estimate the evaporation time of typical drop size distributions over the range of humidification and cooling requirements expected for plants with retrofit FGD systems. The evaporation time is strongly dependent on the maximum size drop in the distribution and the approach to the adiabatic saturation temperature that the gas must be cooled to restore the performance of the ESP.
Catalytic oxidation of groundwater stripping emissions
Authors: Kosusko Michael , Mullins Michael E. , Ramanathan K. , Rogers T. N.
Published: February 2007

Air stripping has been shown to be an efficient and cost effective method of removing volatile organic contaminants from groundwater and soil. The removal of dissolved fuel fractions and chlorinated solvents at efficiencies in excess of 95% has been demonstrated on several occasions. Unfortunately, these contaminants are transferred to the air where they may continue to pose an environmental and health threat. Regulation of such emissions has already been considered in many states including Michigan and California. However, few options are available for their control. Vapor phase carbon adsorption and thermal incineration are the two treatment methods which have been applied most often. These technologies have some disadvantages. Adsorption merely transfers the contaminant to a solid phase, which in turn requires disposal or regeneration. Thermal incineration may be expensive, since it requires a substantial energy input to destroy dilute gas phase contaminants. A new alternative is appearing in the form of catalytic oxidation. Like thermal incineration, it is an ultimate disposal method, but since it operates at much lower temperatures, the energy costs are also lower. This paper reviews the applicability of catalytic oxidation to control groundwater air stripping gaseous effluents with special attention given to system designs and case histories. The variety of contaminants and catalyst poisons encountered in stripping operations are also reviewed.
The effects of commercial landfill bans on waste minimization strategies and treatment performance standards
Authors: Stanczyk Thomas F.
Published: February 2007

Industries and governmental agencies throughout the United States are confronted with a number of issues focusing on the subject of what is, and how, hazardous and contaminated solid waste should be properly managed and controlled. These issues are receiving increased attention as regulatory legislation governing the management of waste magnifies in terms of enforcement and performance standards.
Testing of novel sorbents for H2S removal from coal gas
Authors: Gangwal S. K. , Stogner J. M. , Harkins S. M. , Bossart S. J.
Published: February 2007

Application of zinc ferrite, a regenerable mixed metal oxide, for the removal of H2S from hot coal derived gas streams is limited to a maximum temperature of about 1,250°F (677°C) and to a minimum H2S concentration of about 5 ppmv in the cleaned gas. Four novel sorbents that have shown potential for overcoming the limitations of zinc ferrite [1, 4] were selected for development and bench‐scale testing. Several variations of these mixed metal oxides were prepared, using different amounts of binders. They were tested in the presence of simulated coal gas using a thermogravimetric reactor (TGR) for selection of preparations possessing an adequate combination of reactivity, regenerability, capacity, and strength. Limited bench‐scale tests were conducted in the presence of simulated fluidized‐bed coal gasifier product gases at pressures from 1 to 2 MPa, temperatures from 525°C to 625°C and space velocities from 1,000 to 3000 Nm3/(m3 · h).
Design considerations for natural draft landfill gas incinerators
Authors: Colannino Joseph
Published: February 2007

A consistent methodology regarding major facets of enclosed landfill flare design is presented. A natural draft landfill gas (LFG) incinerator is an enclosed flare consisting of three parts: burner, damper, and stack. Such an incinerator will burn LFG at temperatures up to 1800°F without the need for support gas, or fans to provide draft. Modeling of actual heat release, draft, and stack velocity is a function of many parameters including stack height, incinerator temperature, ambient conditions, stack and damper area, frictional losses, flue molecular weight and heat capacity, among others. The involved variables are simplified to three dimensionless groups that depend on temperature and damper area alone. Graphs are presented for reference, along with a full analytical treatment for those who wish to develop comprehensive modeling.
Field evaluation of nitric oxide abatement with ferrous chelates
Authors: Tsai Susan S. , Bedell Stephen A. , Kirby Larry H. , Zabcik Donna J.
Published: February 2007

The absorption of nitric oxide from flue gas streams presents some unique problems due to its low solubility in conventional scrubbing solutions. A process is being developed that utilizes an electrolytic cell to reduce Fe(III) to Fe(II) and maintain the majority of the iron chelate in the active ferrous state. This process has been tested on an actual flue gas stream and achieved 80% nitric oxide abatement. Further reduction of nitric oxide is possible with increased stages.
Public impact on technical research: The dissimilar fates of two waste gasification projects
Authors: Wentz Charles A. , Galloway Terry R.
Published: February 2007

Gasification is an innovative process that offers considerable potential for highly efficient thermal destruction of hazardous wastes. To explore this potential, plans were made to use gasification to destroy polychlorinated biphenyls (PCBs) in a demonstration project at the University of North Dakota Energy Research Center's pilot‐plant lignite gasifier. The Center received the necessary state and federal environmental permits in July 1986. However, shortly after the permits were granted, public opposition to the PCB program developed. The state operating permit was revoked and the project was terminated. In contrast to the North Dakota experience, research conducted by the Thermolytica Corporation in California has resulted in commercialization of a gasification detoxifier for hazardous waste destruction. The nature and dissimilar fates of the North Dakota and California projects are reviewed.
Utilization of adipic acid byproducts for energy recovery and enhancement of flue gas desulfurization
Authors: Chi C. T. , Lester J. H.
Published: February 2007

Beneficial utilization of two waste streams from adipic acid manufacture is described. The first stream, containing adipic, glutaric, and succinic acids, a mixture referred to as AGS, was found to be very effective in improving the efficiency of limestone scrubbers for removing SO2 from coal‐fired power plant flue gases. A small portion of the AGS stream is also used to convert a contaminated distillation residue from cyclohexanol manufacture into a clean boiler fuel. The residue is an oily waste which contains inorganics and a hard‐to‐separate aqueous phase. The inorganics and aqueous phase are removed by liquid‐liquid extraction in a centrifugal contactor.
Decommissioning old plants (or, you don't close a plant by shutting it down)
Authors: Caputo Dennis L. , Zoch Robert M.
Published: February 2007

Evolving environmental regulations mean that closure of a plant entails more than simply shutting it down. Development and execution of a closure plan that will minimize cost, execution risks, and future liabilities must be approached as a major project for the owner company. This paper discusses the evolving impact of RCRA and CERCLA upon requirements for a plant, and describes a procedure for developing and implementing a closure plan.
Electrophysical sorption of two carbon halogenated solvents onto soil
Authors: Mokrauer J. E. , Kosson D. S.
Published: February 2007

Sorption of halogenated two carbon organic contaminants onto a sandy loam has been found to be controlled by the electrostatic attraction between a slightly negatively (δ−) charged clay particle and a positively (δ+) charged carbon atom within the solvent molecule. Adsorption isotherms for tetrachloroethylene, trichloroethylene, 1,1,1‐trichloroethane, 1,1,2‐trichloroethane, 1,1‐dichloroethane, 1,2‐dichloroethane, and 1,2‐bromochloroethane by a sandy loam indicate that the extent of sorption appears to have a direct functional relationship to the molecular charge distribution within the solvent molecule, and to the atomic radii of the molecular substituents of the contaminant. This theory of adsorption is defined as Electrophysical Sorption (EPS) because it reflects the combination of electrostatic and physical contributions to sorption.
In‐situ air injection, soil vacuum extraction and enhanced biodegradation: A case study in a JP‐4 jet fuel contaminated site
Authors: Cho Jong Soo , Digiulio Dominic C. , Wilson John T. , Vardy James A.
Published: February 2007

The U.S. Environmental Protection Agency (U.S. EPA) and the U.S. Coast Guard (USCG) conducted a joint demonstration of in situ remediation of a JP‐4 jet fuel spill at the USCG Support Center in Elizabeth City, North Carolina. The jet fuel was trapped beneath a clay layer that extended from the surface to a depth of 1.5 m. The water table was 2.0 m below land surface, and jet fuel extended from a depth of 1.0 to 3.5 m. Air was injected under pressure to depress the water table and bring the entire spill into the unsaturated zone, where hydrocarbons could be removed by volatilization and biodegradation. The injected air was recovered through soil vacuum extraction (SVE) at the treatment area. To document actual removal of hydrocarbons, core samples were acquired in August 1992 before air injection, and September 1994 at the end of the demonstration. The spill originally contained 3600 kg of JP‐4. Between the core sampling events, only 55% of the total petroleum hydrocarbons were removed, but more than 98% of benzene was removed. The initial goal was to reduce the concentration of total petroleum hydrocarbons (TPH) to concentrations less than 100 mg/kg soil. This was not accomplished within 18 months of operation. During the period of operation, ground water was monitored for the concentration of benzene, toluene, ethylbenzene, and the xylene isomers (BTEX), and methyl tertiary butyl ether (MTBE). The concentration of BTEX and MTBE in the subsurface was reduced to a very low level, but concentrations of benzene and MTBE in ground water did not meet the EPA drinking water standards in the most heavily impacted wells. The effluent gas from SVE was monitored for the concentration of total hydrocarbon vapors. Based on analysis of soil cores, 2000 kg of TPH was removed during the demonstration. About 1700 kg of hydrocarbon was collected through the SVE system, accounting for most of the actual removal. The rate of biodegradation was estimated from the rate of oxygen consumption in the unsaturated zone when the air injection pumps were turned off. Within the area containing nonaqueous phase liquid (NAPL), the biodegradation rate based on oxygen consumption ranged from 0.72 to 13 mg hydrocarbon/kg soil/day, with an average of 3 mg hydrocarbon/kg soil/day. The mass balance revealed that the contribution of biodegradation was apparently overestimated from oxygen consumption in the soil gas.
Pb mobility and extractant optimization for contaminated soils
Authors: Legiec I. A.
Published: February 2007

Alternative technologies for the remediation for inorganic lead contaminated soils must be evaluated in addition to conventional standard technologies, such as stabilization, to help ensure the best technology was selected for implementation of the remediation solution. Innovative technologies such as extractive soil washing may provide an economical alternative to reaching remediation cleanup goals while, at the same time, protecting human health and the environment.

Extraction of inorganic Pb from contaminated soils has been previously demonstrated using strong acids or chelating reagents. For example, aqueous solutions of chelating agents such as citric acid, diethylenetriaminepentaacetic acid (DPTA), sodium ethylenediaminetetraacetate (EDTA), sodium nitrilotriacetate (NTA) have been used to desorb metals from soils [1, 2]. Also investigated were strong acids, having concentrations up to 2 N, for extraction of metals from sandy soils [3]. Commercial pilot scale systems have been reported to utilize HCl at an extraction pH range of 1.8–2.2 to recover lead from contaminated soils [4]. Chloride complexation of lead can greatly enhance the solubility of lead in solution [5, 6]. Lead also will complex in solution with acetic or citric acid [7].

Incorporating acids or chelating agents with soil washing technologies may extract inorganic Pb species from contaminated soils. However, the feasibility of aqueous based extraction of organic lead species such as tetraethyl lead, and its related byproducts produced by weathering, was unknown. Weathered, contaminated soil core samples were obtained, composited and homogenized in 5 gallon HDPE buckets, and the homogenized sample was characterized. The soils were contaminated predominantly with inorganic Pb as well as trace quantities of organic Pb species. Therefore, a research program was carried out to investigate the feasibility of in‐situ or ex‐situ extractive soil washing to recover inorganic and organic lead contaminants from soil. Literature approaches utilizing acids, chelating agents, or combinations of these, were tested for extraction efficiency. Additional goals included optimizing lead extraction while minimizing extractant chemistry strength to ensure safety and to minimize cost. Both in‐situ and ex‐situ extraction techniques were simulated at bench scale, and the effects of these methodologies on organic lead species were also investigated.
Simultaneous hot desulfurization and improved filtration in coal utilization processes
Authors: Kennedy Gina , Eggerstedt Paul , Zievers James F. , Zievers Elizabeth C.
Published: February 2007

Much of America's vast coal reserves will remain unusable until technology capable of the effective, economic removal of particulate and sulfur emissions becomes more highly developed. Traditional calcium based sorbents, as well as more novel metal oxide sorbents, such as zinc ferrite and zinc titanate are effective in sulfur removal, but can be costly and do little to mitigate particulate within high temperature coal combustion and gasification streams. An innovative approach involving the use of classified, spent metal oxides appears to be a promising resolution to the particulate and sulfur dilemmas associated with most coal utilization processes. A number of such waste metal oxides have been tested, to assess their capacity for sulfur capture in sulfur laden oxidizing and reducing environments. Inert materials such as silica sand and traditional sorbents such as limestone and dolomite, were also evaluated to serve as reference data. Experimentation proved that the “once‐through” spent metal oxide sorbents can effectively remove sulfur while simultaneously increasing the permeability of dust collected at downstream ceramic filter stations. Additionally, spent metal oxides are generated in large quantities as a result of metal processing, smelting, and refining operations, and are generally available at little or no charge, for use as cost effective sorbents in coal combustion and gasification processes. This paper suggests the use of such spent metal oxides in place of calcium based or regenerable pelletized metal oxide sorbents for the removal of sulfur dioxide (SO2) and hydrogen sulfide (H2S) from gas streams containing these components.
Parametric testing of coal electrostatic precipitator performance
Authors: Cañadas L. , Navarrete B. , Ollero P. , Salvador L.
Published: February 2007

The effect of internal geometry, electrode type, and operating conditions on the performance of a coal electrostatic precipitator (ESP) has been analyzed by means of an extensive parametric testing program. Tests under different conditions of plate spacing, discharge electrodes, gas velocity, and energization wave form have been performed using two extreme coal types, with very high and low resistivity ashes, respectively. The study was made by means of a pilot installation operating with a flue gas slipstream drawn upstream of a power plant ESP. The experimental plant includes a specifically designed pilot ESP, able to admit an internal modification of plate spacing and electrode type. The ESP is equipped with a microprocessor controlled power supply which can generate both continuous and intermittent rectified current.

The measured sensitivity of the precipitation process to the dust properties, filter configuration, electrode type, and energization method is presented, covering both the ESP efficiency evolution and the associated power consumption. The results of this work allow to extract practical conclusions about specification of ESP design and size for a given application, and assess the conditions in which use of wide plate spacing, new electrode geometries, or intermittent current are actually advantageous.
Photocatalyzed oxidation of phenol in water using a cocurrent downflow contactor reactor (CDCR)
Authors: Winterbottom J. M. , Khan Z. , Boyes A. P. , Raymahasay S.
Published: February 2007

The oxidation of aqueous solutions of phenol as a typical model pollutant has been carried out in the presence of an ultra‐violet (UV) irradiated TiO2 catalyst in a CDC reactor. The CDCR was fitted with internally mounted 30 W and 1.0 kW UV lamps. The reactions were carried out at 40–50°Cand 202.6 kPa, with the reactor being operated in closed loop recycle mode and suspended catalyst being recirculated. The CDCR is a device of high mass transfer efficiency, giving unusually large gas hold‐up (approximately 50%). The CDCR was operated (i) with oxygen mass transfer and dissolution in the zone above the UV source and (ii) with oxygen dispersion and mass transfer occurring along and around the lamp housing. Using the higher powered lamp, 100% conversion of phenol was obtained from solutions containing 100 mg/dm3. Under specific conditions the presence of TiO2 catalysts was observed to give the most rapid oxidation degradation of the phenol.
A database on water quality of the mississippi river
Authors: Preslan Janet E. , Belkhouche Boumediene , Swalm Christopher M. , Hughes Janet M. , Chen Hsiao‐Lin , Henry Melanie , Lin Daryl , Bakeer Reda M. , Englande A. J. , Demtchouk Irina , Anderson Mary B. , Regens James L. , Means Jay C. , Bollinger James E. , Steinberg Laura J. , Luna Ronaldo , Hernandez Raul , Hartley William R. , George William J.
Published: February 2007

A water quality GIS/database has been developed for the Mississippi River within the state of Louisiana. Existing ambient water quality data (1.3 million records) and records of river stage and discharge for the river and its tributaries have been acquired from government agencies, industry, and research projects. Data were initially reviewed to validate information quality. They have been incorporated into an Oracle® database created to provide rapid data searches and retrieval of information through a menu‐format user interface. Descriptive information about sample collection and analysis methods are included, as well as government advisory criteria which provide ecological and human health perspectives to assist in data interpretation. GIS software utilizes electronic base maps which have been developed in Arc/Info® and ArcView® data formats to generate geographic displays and graphical representations of the data. Examples of the capabilities of the system are included for data on mercury, phosphates, and nitrates. The temporal trends in the concentrations of representative water quality parameters are tabulated for a selected segment of the river.
Biological treatment of salty wastewater
Authors: Smythe Gary , Matelli Guy , Bradford Mike , Rocha Carlos
Published: February 2007

Industrial wastewater containing high concentrations of salt can be treated in biological treatment systems. However, the high salt contents tend to add to the cost and sensitivity of the treatment system. Wastewater containing high concentrations of salt can be handled in the following types of treatment systems:

Conventional activated sludge systems can handle up to 5% salt.

Anaerobic systems can handle up to 1.5% salt.

Specialized systems, such as fluid bed/SBR/Zeno‐Gem®, can handle up to 10% salt.

Special bacteria can be used for treatment of wastewater containing up to 15% salt.

This paper discusses three wastewater treatment projects that involved wastewater with high concentrations of salt, up to 10% salt. This paper also summarizes the information collected from literature searches conducted as part of the projects.
Heavy metal soil remediation: The effects of attrition scrubbing on a wet gravity concentration process
Authors: Marino Michael A. , Brica R. Mark , Neale C. Nelson
Published: February 2007

The US military has historically conducted activities which have either directly or indirectly contributed to environmental contamination. Metal contaminated soil at military sites has resulted from operations such as weapons production, small arms training activities, metal cleaning, and metal plating activities.

Soil washing is an effective approach to the treatment of contaminated soils employing both physical and chemical separation techniques. Physical separation methods encompass many different unit operations including screening, grinding, flotation, hydroclassification, attrition scrubbing and gravity concentration such as tabling and spiraling. The primary focus of this paper will be to address the effects of attrition scrubbing (an abrasive soil particle to soil particle interaction in a high solids environment), on a gravity concentration process.

Soil from an Army small arms training range with lead contamination in the bulk soil at approximately 40,000 mg/kg, was evaluated using a WEMCO® Laboratory Attrition Scrubber in conjunction with a Wilfley® Laboratory Wet Shaking Table. Results indicate attrition scrubbing enhanced the physical separation process on the wet shaker table by liberating the Pb contamination from the bulk soil, which resulted in a large volume of clean soil while simultaneously producing a small volume of Pb concentrated soil. Laboratory tests indicate over 96% of the contamination could be concentrated on 20% of the original soil mass.
A simplified approach for preliminary design and process performance modeling of soil vapor extraction systems
Authors: Staudinger Jeff , Roberts Paul V. , Hartley James D.
Published: February 2007

While soil vapor extraction has been widely utilized as a remedial action technology over the past decade, design and associated process performance modeling of full‐scale systems continues to be frequently based on the results of pilot‐scale treatability tests. To aid engineers in conducting preliminary scoping studies without the benefit of such treatability data, a relatively simple approach, consisting of linked design and process performance elements, was developed and subsequently incorporated into a spreadsheet format for rapid project evaluation purposes. Under this approach, a preliminary design is specified via a set of baseline values which vary based on the predominant soil type encountered at a particular site. Process performance is then mathematically modeled by a semi‐empirical relation accounting for non‐equilibrium (mass transfer) effects via use of a lumped parameter, the venting efficiency factor (η). Values for η vary based on characterization of soil heterogeneity. The low values cited for η (on the order of 0.02–0.20) reflect the relative inefficiency of field venting operations (due to inherent mass transfer limitations) when compared to idealized conditions. Validation results, considering two case studies reported in the literature, indicate that the approach developed provides reasonably accurate predictions. Evaluation of a hypothetical case study reveals that the number of extraction vents required as well as the number of pore volumes of soil vapor that must be extracted for effective remediation can vary by an order of magnitude depending upon the particular soil matrix encountered.
Remediation of polychlorinated biphenyl contaminated soils/sediments by supercritical fluid extraction
Authors: Chen P. , Zhou W. , Tavlarides L. L.
Published: February 2007

Studies of polychlorinated biphenyl (PCB) desorption from soils have been conducted in a laboratory scale supercritical fluid extraction (SEF) unit to provide information for soil remediation. The results demonstrate the effectiveness of SFE as a promising technology for the clean up of PCB contaminated soils/sediments. After 30 minutes of extraction at 40°Cand 100 atm, more than 86% of PCBs in real world Hudson River sediment and 92% in St. Lawrence River sediment were removed. The extraction of PCBs from spiked samples showed even higher efficiencies. Various effects such as temperature, pressure, cosolvent, sample water content, and soil/sediment type on PCB desorption have been investigated. The sample water content and the presence of cosolvent were shown to be the most important factors affecting desorption of PCBs. The results show that PCBs in real world samples are more tightly bound than in spiked samples. The desorption behavior of individual PCB congeners in various samples has been investigated. The results demonstrate no relative accumulation of the most environmentally threatening PCB congeners throughout the extraction process.
Application of design for environment concepts to the semiconductor industry
Authors: Beu Laurie , Mendicino Laura
Published: February 2007

Motorola has traditionally focused on cost, yield, performance, and logistics as primary drivers for decision‐making. In the semiconductor industry, environmental issues have resulted in major modifications of tools and process steps because they are not routinely considered when making process design and manufacturing choices, nor is their impact on cost, yield, and cycle time. Certain business driving forces, such as cost, sustainability of processes/tools, time to market, market access, and market share, are leading Motorola to a cultural change in which environmental impacts must be considered during product and process design; however, design and process engineers have not been able to adequately address these impacts. Motorola's Advanced Process Research and Development Laboratory (APRDL) in the Semiconductor Product Sector (SPS) has recognized this and has established its own environmental group (separate from the site environmental compliance group) to implement a Design for Environmental (DFE) strategy. This group works with several project teams to address environmental issues in process development. To empower engineers to consider the environmental impacts of their materials and processes at the earliest possible stage, the APRDL environmental group has also developed a DFE training course. This web‐based course targets semiconductor design and process engineers and is available through Motorola University, the corporate training institution.

In the broadest terms, DFE is a systematic management approach for evaluating and mitigating environmental concerns at the earliest possible stages of process design or product life cycle. It includes ongoing evaluation during the product life cycle, while optimizing the balance between environmental priorities and factors such as cost, yield, cycle time, performance, etc. This optimization requires that Motorola make value judgments based on the best information available. The course is designed to provide semiconductor engineers with the neccesary background to understand the concepts of DFE and the tools to incorporate consideration for environmental impacts into their daily routine with‐qut adding a significant burden to their workload.
Evaluating acids and chelating agents for removing heavy metals from contaminated soils
Authors: Neale C. Nelson , Bricka R. Y , Chao Allen C.
Published: February 2007

The prevalence of heavy metal soil contamination at Army facilities poses a serious threat to human health and the environment. To address this problem, the US Army Engineer Waterways Experiment Station in Vicksburg MS is developing a mobile piot‐scale soil washing treatment facility that can be used to remove metals from the contaminated soils. To support this project, laboratory studies were conducted on both acids and chelating agents to evaluate their ability in extracting heavy metals from contaminated soils. Eight soils contaminated with lead, cadmium, and chromium were selected for use in this study. Contaminant concentrations in the various soils ranged from 4,000–30,000 mg/kg lead, 40–1,000 mg/kg cadmium, and 500–2,000 mg/kg chromium.

The results indicated that, before a full‐scale clean‐up is initiated, a preliminary investigation is needed to determine principal contaminants of concern, their concentrations, and soil type followed by treatability studies to determine optimal reagent and concentrations of reagents for cleanup. Specific results from this study also indicated that Cd was the easiest metal to remove from soils followed by Pb and Cr. The results also suggested that the strong acids and chelating agents were both effective extracting agents, and the latter group of compounds may be more useful in soil washing because they are less harmful to the soil environment. Finally, higher initial concentrations of metal contaminants in the soil resulted in greater metal removal efficiencies using the reagents.
Treatability of oil shale gas condensate wastewater
Authors: Lewis Richard S. , Rawlings Gary D. , Day Duane R.
Published: February 2007

Laboratory‐scale experiments with an actual modified in‐situ gas condensate are used to assess the suitability of the available processes.
Packed and tumbled‐bed electrochemical reactors for metals recovery
Authors: Tison Richard P.
Published: February 2007

A simple approach for use in the early stages of the development and screening of electrochemical reactors.
Wastewater treatment at a coal‐liquefaction facility
Authors: Sapp James B.
Published: February 2007

Operating experience in wastewater treatment at the coal‐liquefaction facility in Wilsonville, Alabama, confirms that synfuel plant wastewater can be successfully treated.
U.S. environmental laws and their impact on American steel
Authors: Margolin Stanley V.
Published: February 2007

Arthur D. Little casts an authoritative eye on the real effect of government regulation on the competitive position of the U.S. steel industry.
Environmental assessment of the barrel and drum reconditioning industry
Authors: Touhill C. J. , James Stephen C.
Published: February 2007

If environmental‐quality regulations are adhered to, steel‐drum reconditioning can be an effective way to control indiscriminate disposal.
Activated carbon regeneration apparatus
Authors: Jones Jerry L. , Gwinn Julia E.
Published: February 2007

An experimental investigation aimed at determination of the rate and extent of thermal regeneration of activated carbons.
Boron control in power plant reclaimed water for potable reuse
Authors: Wong Joseph M.
Published: February 2007

On the basis of test data, strong‐base anion exchange is recommended as a boron‐control process for the treatment of evaporator effluent.
Problems in calculating fugitive‐dust emissions for coal‐handling facilities and storage piles
Authors: Stein David , Crow Glenn
Published: February 2007

There is an urgent need for more study of physical processes and the behavior of coal dust as it settles to the ground.
Improved estimates of sulfate dry deposition in Eastern North America
Authors: Wesely Marvin L. , Shannon Jack D.
Published: February 2007

Seasonable sulfate dry deposition, computed numerically with a Lagrangian regional‐scale model, appears to be smaller than previous estimates.
New solutions to industrial waste management
Authors: Curran Linda M.
Published: February 2007

The modification of existing processes must be considered in the search for cost‐effective solutions in the treatment of hazardous wastes.
Surface area of calcium oxide and kinetics of calcium sulfide formation
Authors: Borgwardt Robert H. , Roache Nancy F. , Bruce Kevin R.
Published: February 2007

Details of a new limestone injection multistage burner aimed at reducing harmful emissions from existing power plants.
The stripping of organic chemicals in biological treatment processes
Authors: Truong Kim N. , Blackburn James W.
Published: February 2007

A new approach to prediction of the fates of organic chemicals in biological processes.
A review of current diglycolamine® agent gas treating applications
Authors: Moore Tom F. , Dingman John C. , Johnson Fred L.
Published: February 2007

The use of DGA® gas treating agent can result in significant savings over other sweetening processes.
Anaerobic treatment of fermentation wastewaters
Authors: Szendrey L. Michael
Published: February 2007

A case history from Puerto Rico on the technology and economics of a new anaerobic‐treatment filtration process.
Calcium sulfite hemihydrate: Crystal growth rate and crystal habit
Authors: Tseng Philip C. , Rochelle Gary T.
Published: February 2007

The crystal growth rate of CaSO3 · 1/2H2O was measured by a pH‐stat method in aqueous solution with pH 3.5 to 6.5, 1 to 25 mM dissolved sulfite, 0.01 to 0.3 M Ca++, and 0 to 25 mM sulfate. The growth rate was a strong function of relative supersaturation and was strongly inhibited by dissolved sulfate. The growth rate per unit BET surface area, R' (mole/cm2‐min), is given by: 9.7 × 10−4 exp (−10250/RT) × (RSCaSO3−1)2 × RSCaSO4−1, where RSCaSO3 and RSCaSO4 are the relative saturations with respect to calcium sulfite and gypsum, respectively. Scanning electron microscopy and IR spectroscopy demonstrated that solids generated in the presence of dissolved sulfate contained solid solution sulfate and crystallized as agglomerates of very thin platelets. In the absence of solid or dissolved sulfate the solids were agglomerates of well‐informed columnar, hexagonal crystals.
Modeling the transport of 2,3,7,8‐TCDD and other low volatility chemicals in soils
Authors: Freeman Raymond A. , Schroy Jerry M.
Published: February 2007

A model has been developed to describe the transport of low volatility organic chemicals in a column of soil. The mathematical model calculates the rate of movement through the soil by solving the dynamic material and energy balances around the soil column. The model is used to make predictions on the transport of 2,3,7,8‐tetrachlorodibenzop‐dioxin (TCDD) at the Eglin Air Force Base Agent Orange biodegradation test plots. The model predicts a vertical movement of TCDD, buried in 1972, through the soil column. Soil column profile data confirm the vertical movement of TCDD.
Dissolution rate of calcium sulfite hemihydrate in flue gas desulfurization processes
Authors: Teseng Philip C. , Rochelle Gary T.
Published: February 2007

The rate of calcium sulfite dissolution in slurry scrubbers and hold tanks for flue gas desulfurization affects SO2 absorption, limestone utilization and sulfite oxidation. The dissolution rates of calcium sulfite were measured by the pH‐state method. A mass transfer model was developed assuming that calcium sulfite particles behave as spheres in an infinite stagnant solution. The model combined with the Bechtel‐modified Radian solution equilibrium program successfully predicts calcium sulfite dissolution rates at pH 3.5 – 5.5, 23 and 55°C, 0.001 – 0.3 M Ca++ and 2 – 25 mM dissolved sulfite. The effects of sulfate content in solids and liquids and particle size/shape were also studied.

At conditions typical of flue gas desulfurization processes calcium sulfite dissolution was controlled by mass transfer, not surface reaction kinetics. Dissolution was fast at low pH and slowed near the equilibrium pH determined by dissolved Ca++ and SO3= concentrations in the aqueous solutions, Ksp of the CaSO3 · 1/2H2O solids, and temperature. The presence of dissolved Mg++ increased the equilibrium pH and enhanced the disolution rate. The presence of dissolved sulfate reduced the dissolution rate and the equilibrium pH. The effect of sulfate was not adequately described by the mass transfer model.
Health risk comparison between groundwater transport models and field data
Authors: Hwang Seong T.
Published: February 2007

The potential of ground water contamination is one of the major concerns over land disposal of hazardous waste. Risk assessment requires information on groundwater concentrations of contaminants at the exposure location. Results are presented of case studies comparing health risk assessment and plume delineation based on state‐of‐the‐modeling and monitoring data.
Economics of membrane treatment of wastewaters containing firefighting foam
Authors: Chan Deh Bin , Chian Edward S. K.
Published: February 2007

Aqueous Film Forming Foam (AFFF) is the most effective fuel/oil fire fighting agent. Wastewater generated from firefighting training facilities contains mixtures of AFFF, residual free fuel oil, emulsified fuel oil, gasoline, purple K (PKP), and miscellaneous combustion products. Membrane treatment of these wastewaters by a two stage ultrafiltration (UF) and reverse osmosis (RO) process appearas economically attractive. Cost effectiveness of the membrane process is compared with a rotating biological contactor (RBC) and a carbon adsorption system.
The effect of weak chelating agents on the removal of heavy metals by precipitation processes
Authors: Ku Young , Peters Robert W.
Published: February 2007

Particle size distributions and heavy metal removals are presented for hydroxide precipitations and heavy metal removals are presented for hydroxide precipitation and sulfide precipitation of zinc and cadmium in the presence of several weak complexing agents, namely citrate, tartrate, and ammonia. The pH was held constant at pH 10.0 in these experiments. The presence of these weak complexing agents had little effect on the chemical equilibrium for both the hydroxide and sulfide systems due to their weak complexing ability with metal ions. The presence of the complexing agents does affect the particle size distribution, generally forming smaller particles. Particle size distributions are presented for the Zn(OH)2, ZnS, Cd(OH)2, and CdS systems (at pH 10.0) in the presence of the chelating agents citrate, tartrate, and ammonia. Sulfide precipitation exhibits a better particle size distribution and settling characteristics than the corresponding metal hydroxide precipitation for both zinc and cadmium.
Application of aluminas in water treatment
Authors: Fleming Hubert L.
Published: February 2007

Removal of contaminants from process and waste water by adsorption with transition aluminas is receiving increased attention. As separation requirements become more stringent, the advent of controlled surface chemistry and pore morphology in adsorbent processing has resulted in innovative application of these materials to water treatment. This paper reviews current technology and examines emerging processes utilizing these versatile materials.
Utilization of residuals from flue gas desulfurization
Authors: Kappe J. , Ellison William
Published: February 2007

Diverse large‐scale sources of FGD gypsum, the plentiful waste by‐product from SO2 emissions cleanup in major industrial countries, are characterized in terms of properties including crystal form and contained impurities that affect commercial usability. New technology to expand FGD gypsum usage by economical conversion to alpha hemihydrate of calcium sulfate is detailed.
Evaluation of air emission release rate model predictions of hazardous organics from land treatment facilities
Authors: Ryan Dupont R.
Published: February 2007

The Thibodeaux‐Hwang Air Emission Release Rate (AERR) model for volatile emissions from land treatment systems was evaluated on a constituent specific basis utilizing API Separator Sludge and a Slop Oil Emulsion Solids waste stream applied to laboratory sand and soil microcosms. Literature correlation equations were used for estimating air:oil partition coefficients necessary for model input. Measured data suggested that vapor partitioning and retardation by soil organic matter are of minor importance in the overall vapor soil transport process, and that volatile organic vapor soil diffusion can be adequately described simply by the physical environment through which the vapor is traveling.

Subsurface waste application produced a two‐ to ten‐fold decrease in emission rates as predicted from the Thibodeaux‐Hwang AERR model compared with surface application conditions. Measured data followed the predicted linear relationship of flux rate versus 1/t1/2 indicating the diffusional nature of soil vapor movement. The Thibodeaux‐Hwang AERR model and the parameter estimation approach consistently overestimated flux rates for the pure constituents by only a factor of approximately 2 to 10, and consequently appear quite effective for the estimation of volatile organic emissions from complex waste/soil systems.