bluuebunny/crossref_metadata_2025 huggingface dataset:
Groundwater air stripping: Effect on water toxicity
Authors: Eldridge R. Bruce , Simpson Cindy W. , Elliott David J.
Published: February 2007

An air stripping unit was designed to reduce groundwater hydrocarbon content and biotoxicity to acceptable levels. A pilot plant study was conducted to determine the water treatability and to optimize the commercial unit design conditions. A measurement of the pilot plant effluent toxicity was obtained from “Microtox” analysis and rigorous bio‐assays. These results indicated that reduction of the water hydrocarbon content to permitted discharge limits was accompanied by the elimination of water toxicity. The Onda mass transfer model was used to prepare the commercial unit design. A post‐installation evaluation indicated that the model gave a good representation of the commercial unit performance. Toxicity reductions observed in the pilot plant were also observed in the commercial unit.
Crossflow air stripping and catalytic oxidation of chlorinated hydrocarbons from groundwater
Authors: Gavaskar Arun R. , Kim Byung C. , Rosansky Stephen H. , Ong Say K. , Marchand Edward G.
Published: February 2007

This paper describes air stripping of chlorinated hydrocarbon contaminants from groundwater in a crossflow air stripping tower and destruction of the organic compounds by catalytic oxidation. Crossflow stripping has an advantage over conventional countercurrent stripping. In typical stripping operations, the mass transfer coefficient is insensitive to the velocity of the gas stream. The crossflow stripping tower is a geometry that increases the cross section of gas flow while making minimal disturbances to the liquid flow, allowing high gas‐liquid ratios without flooding. By increasing the flow cross section for the gas stream, pressure drop (and thus fan power) can be reduced significantly.

A field demonstration of the crossflow column was performed at a contaminated groundwater site. The groundwater was pumped out and sent to two 17‐ft‐high (5.2‐m) towers in a parallel arrangement. One tower was a crossflow air stripper and the other a conventional countercurrent design. The performance of the two was compared. The key organic species targeted was dichloroethane, which has a low Henry's law constant. Three different baffle configurations were tested in the crossflow tower.

The results of this demonstration were used to develop design criteria for crossflow air strippers to be used for destruction of halogenated hydrocarbons.
Estimation of methodology and validation of particulate entrainment in a pilot‐scale rotary kiln‐based hazardous waste incinerator
Authors: Acharya Prakash , Prabhu Sachin , Barkdoll Michael
Published: February 2007

Combustion gas particulate entrainment from rotary kiln hazardous waste incinerators (HWI) is a necessary design data requirement because of its impact on the design and operation of the downstream process equipment. The particulate leaving the rotary kiln off‐gases may slag in the secondary combustion chamber (SCC). The potential to slag and the problems slagging can cause are dependent upon the SCC burner design, the mineralogical composition of the praticulate, and the SCC operating temperature.

Some entrained particulate may adhere to the walls or fall out in the SCC as a dust/stag; the remainder of the particulates will be conveyed by the flue gas to the downstream air pollution control (APC) system. If a wet APC system is used, the particulates would be discharged to a wastewater treatment system (WTS) or publicly operated treatment works (POTW).

A literature search was conducted to determine the knowledge base for particulate carry‐over from a countercurrent rotary kiln processing sedimentary solids. No data existed for this type soil. A pilot test was, therefore, conducted to experimentally measure the potential entrainment rate of this material. A detailed discussion of the entrainment mechanisms, pilot test equipment, sampling procedure, test conditions simulating the commercial operation, particle size distribution (PSD) of the ash sample, percent carry‐over rate, and measured PSD of the kiln particulate carry‐over are presented in this article. A mathematical model was developed by the authors to predict the pilot test results. The PSD of incinerator ash was used to calculate percent carry‐over rate and PSD of the entrained solids. A comparison of experimental versus estimated results for estimating entrainment are presented in this article.
Optimizing remedial action implementation at the C & R battery company superfund site
Authors: Moore Jeffrey W. , Claypool John E.
Published: February 2007

Adding value to hazardous waste site remediation projects during early stages is paramount to avoid unnecessarily costly design and construction issues. Privatization of the C & R Battery Company Superfund site remediation provided opportunities for large cost savings which appeared to have been excluded while the project was federally led. In governmentally‐led projects, formal value engineering studies may not reduce final project costs because implementable cost saving alternatives may be rejected or ignored due to administrative objectives and pressures. Over reliance on the effectiveness of the value engineering study to find and add economics in a project may also have contributed to a less innovative design from the outset. In the case of the C & R Battery Company Superfund site, a formal value engineering study was performed at the 90 percent completion point in the Remedial Design (RD) under the auspices of the United States Environmental Protection Agency (EPA). As a result of the late point in the project at which the formal value engineering study was performed, many cost saving opportunities were lost. After privatization, re‐evaluation of basic design concepts provided for tremendous cost savings, but they were limited to items which could be implemented without necessitating administrative approvals or upsetting the schedule mandated by the EPA.
Reduction of effluent toxicity for a printed circuit board facility
Authors: Curtis Michael D. , Klei Herbert E. , Cooney John D. , Ertl Rainer
Published: February 2007

Resulting from 1987 modifications of the Clean Water Act, whole effluent toxicity became a new parameter for numerous NPDES discharges. Recently, a Connecticut printed circuit board manufacturer undertook whole effluent toxicity testing and subsequently, an effluent Toxicity Identification and Reduction Evaluation (TI/RE). The TI/RE consisted of parallel efforts to eliminate or reduce the sources of effluent toxicity to a vertebrate and an invertebrate species. Testing showed that effluent toxicity to the fathead minnow, Pimephales promelas, and the daphnid, Daphnia pulex, was due to different causes. The primary toxicant identified in fathead minnow testing was shown to be unionized ammonia, generated primarily from circuit board etchant rinse processes. The primary toxicant in daphnid testing was shown to be an organic surfactant/defoamer used in the resist strip process. Efforts to identify the organic surfactant were successful and resulted in the isolation of a phosphate ester as the primary cause of toxicity to the daphnids. Product substitution was easily accomplished and resulted in marked reduction of effluent toxicity to Daphnia pulex. To reduce effluent ammonia toxicity, etchant rinse ammonia loadings will be reduced or eliminated from the process. The ammonia reduction program is discussed. Attainment of ‘toxicity permit limits’ will be achieved with use of pollution prevention/waste minimization techniques and without the need for additional facility waste treatment processes.
Removal of elemental phosphorus from electric furnace sludges of various origins
Authors: Jefcoat Irvin A. , Potluri Sundeep
Published: February 2007

A method developed by researchers at the University of Alabama has successfully eliminated the toxic and flammable characteristics of elemental phosphorous from by‐product sludges produced from operations of electric furnaces at widely separated facilities. The removal process is first order with respect to elemental phosphorus concentration with a rate constant of 0.02 min−1. The residuals produced contain cadmium, chromium, and lead concentrations above the TCLP limit and thus will require further treatment.
Stripping of TCE from water at low air/water ratios
Authors: Wang Hsi‐Chun Alister , Chang Wenji Victor , Michiels Alan , Dickeson Dan
Published: February 2007

Trichloroethylene was removed from water by air stripping in a packed column using low air/water ratios, and the measured removal efficiencies were used to correlate the height of a transfer unit using a model which takes into account both liquid‐ and gas‐phase resistance to mass transfer. The resulting correlation was used to optimize the design of a combined air stripper and offgas treatment system. Estimated overall cost savings of up to 26% compared to conventional air strippers can be realized by use of the optimum air/water ratio.
Integrating low‐NOx burners, overfire air, and selective non‐catalytic reduction on a utility coal‐fired boiler
Authors: Hunt Terry , Muzio Larry , Smith Randy , Hanley Thurston J.
Published: February 2007

Public Service Company of Colorado (PSCo), in cooperation with the U.S. Department of Energy (DOE) and the Electric Power Research Institute (EPRI), is testing the Integrated Dry NOx/SO2 Emissions Control System. This system combines low‐NOx burners, overfire air, selective non‐catalytic reduction (SNCR), and dry sorbent injection with humidification to reduce by up to 70% both NOx and SO2 emissions from a 100 MW coal‐fired utility boiler. The project is being conducted at PSCo's Arapahoe Unit 4 located in Denver, Colorado as part of the DOE's Clean Coal Technology Round 3 program. The urea‐based SNCR system, supplied by Noell, Inc., was installed in late 1991 and was tested with the unmodified boiler in 1992. At full load, it reduced NOx emissions by about 35% with an associated ammonia slip limit of 10 ppm. Babcock & Wilcox XCL® burners and a dual‐zone overfire air system were retrofit to the top‐fired boiler in mid‐1992 and demonstrated a NOx reduction of nearly 70% across the load range. Integrated testing of the combustion modifications and the SNCR system were conducted in 1993 and showed that the SNCR system could reduce NOx emissions by an additional 45% while maintaining 10 ppm of ammonia slip limit at full load. Lower than expected flue‐gas temperatures caused low‐load operation to be less effective than at high loads. NOx reduction decreased to as low as 11% at 60 MWe at an ammonia slip limit of 10 ppm. An ammonia conversion system was installed to improve performance at low loads. Other improvements to increase NOx removal at low‐loads are planned. The combined system of combustion modifications and SNCR reduced NOx emissions by over 80% from the original full‐load baseline.
Mass transfer correlations for air stripping towers
Authors: Djebbar Yassine , Narbaitz Roberto M.
Published: February 2007

The overall system‐specific liquid phase mass transfer coefficient, KL a, is the most important parameter in the design of air strippers. Designers frequently estimate KL a using a mass transfer correlations to avoid the cost of pilot tests. This paper evaluates the well‐accepted Onda correlations using a newly developed data base. Predictions based on the Onda correlations systematically overestimated KL a for packings typically used in full‐scale applications. They had an average error of ±40% and an average standard deviation of ±47%. The overestimation was a function of the packing diameter. A simple equation was developed to correct the Onda overestimation for packings larger than 1 inch (2.54 cm) in diameter, and it yielded predictions within ±20% range. The experimental KL a values obtained in this study varied with packing depth contradicting a basic assumption of the mass transfer theory, i.e., that KL a spatially is constant. Also, the effect of measurement errors of the variables involved in the calculation of both the experimental and the predicted KL a values were investigated. A large part of the observed difference between experimental and Onda predictions was attributed to a lack of fit of the Onda model. Thus, the quality of the predictive correlations can be improved.
Hot gas desulfurization with Phillips Z‐Sorb sorbent in moving bed and fluidized bed reactors
Authors: Khare G. P. , Delzer G. A. , Kubicek D. H. , Greenwood G. J.
Published: February 2007

Phillips Z‐Sorb sorbents have been evaluated successfully as regenerable sorbents for hydrogen sulfide in the fuel gas that is produced in a clean coal technology power plant. Tests have been carried out in fixed‐, moving‐, and fluid‐bed applications. The fixed‐bed tests completed at the Morgantown Energy Technology Center showed that Phillips Z‐Sorb sorbent performed better than zinc titanate. The performance of Phillips Z‐Sorb sorbent in a moving‐bed application was very encouraging. The sorbent flowed well, H2S was reduced to less than 50 ppm at the absorber outlet over long periods and post‐test analysis of the sorbent indicated very low sulfate levels at the regenerator exit. The fluidizable version of Phillips Z‐Sorb sorbent was tested in Research Triangle Institute's high temperature, high pressure, semi‐batch, fluidized‐bed reactor system. In a life cycle test consisting of 50 cycles of sulfidation and regeneration, this sorbent exhibited excellent activity and regenerability. The sulfur loading was observed to be 90 + percent of the theoretical capacity. The sorbent consistently demonstrated a sharp regeneration profile with no evidence of sulfate accumulation.
Biological treatability studies: New regulations require a new approach
Authors: Eckenfelder W. Wesley
Published: February 2007

In the past, biological treatability studies were directed toward defining effluent BOD and TSS. Recent regulations now require effluent limitations on volatile organic carbon, specific priority pollutants, aquatic toxicity and in many cases nitrogen for complex wastewaters. This, in turn, has changed the focus of biological treatability studies.

It is assumed that a screening protocol has been employed to define biological treatment as a candidate process [1].

(a) Priority Pollutants—If one or more priority pollutants are a permit issue, a fed batch reactor (FBR) is run using acclimated biosolids to determine the maximum degradation rate, qm, and the half velocity constant, Ks. From these data, the required SRT to meet effluent limitations can be computed.

(b) Aquatic Toxicity—If the wastewater exhibits aquatic toxicity in addition to priority pollutant requirements, bioassays are run on the biological units. Effluent toxicity and COD are tracked with time. Since effluent toxicity is frequently associated with soluble microbial products (SMP), the SMP is estimated from the effluent COD over time of aeration.

(c) Nitrogen—Many organics including SMP are inhibitory to nitrification. The nitrification rate should be determined on the effluents using seeded NH4Cl as a control. From these data, the required SRT can be computed.

This paper reviews the required protocols and presents several case histories from the chemical and pharmaceutical industry.
Criminal sanctions under environmental statutes
Authors: Holden Robert E.
Published: February 2007

This paper surveys the criminal provisions of federal environmental statutes. It discusses whether the violation be “knowing” or intentional and when corporate employees may be liable for criminal violations without any personal involvement in environmental crimes. The paper surveys the criminal provisions under the Clean Water Act, the Clean Air Act, the Resource Conservation and Recovery Act, the Comprehensive Environmental Response Compensation and Liability Act, the Emergency Planning and Community Right‐to‐Know Act and the Toxic Substances Control Act.
Pollution prevention possibilities for small and medium‐sized industries: Analysis of the WRITE projects
Authors: Licis Ivars J.
Published: February 2007

This paper summarizes the results of the Waste Reduction Innovative Technology Evaluation Program (WRITE), an EPA pilot program with six (6) states and one (1) local government, to identify priority needs at the respective governmental level, find promising waste minimization technologies and perform an evaluation to determine performance, pollution prevention (P2) impact and costs. The research concentrated on environmental problems and P2 opportunities for small to medium‐sized industries, technology at pilot‐ or full‐scale, and use of voluntary business/state/EPA partnerships. A total of 41 technologies were tested and evaluated. The types of industries and processes included were coating, depainting, electronics, metal plating and finishing, printing, surface cleaning, steel, and a number of miscellaneous categories. Many of the technology applications evaluated were able to list cost savings coupled with reduced or eliminated waste streams. It was found that technology benefits are largely application specific. However, favorable (or even unfavorable) findings for one application can be useful as a beginning for estimating other beneficial uses.
Using LCA‐based approaches to evaluate pollution prevention
Authors: Curran Mary Ann
Published: February 2007

This paper describes how a Life‐Cycle Assessment (LCA) approach can be a beneficial support tool in assessing pollution prevention (P2) opportunities. LCA evaluates potential upstream and downstream impacts that may result from the implementation of a P2 activity, including impacts during resource extraction, manufacturing, product use and maintenance, and final disposal.

Two such LCA‐based approaches, developed by EPA's Pollution Prevention Research Branch, are presented. The first approach is a preliminary P2 Factors methodology that was developed using the lithographic printing industry as the test industry. Two P2 activities were selected for study: solvent substitution in blanket and press wash and waterless versus conventional dampening fountain system printing. The second approach assesses P2 progress when incorporating product re‐design, reformulation or replacement. The P2 Progress method compares the pollution generated by the manufacturing, use and disposal of the original product with the modified product. A fictionalized reformulation of rubber cement demonstrates the P2 Progress method.
A review of pollution prevention depainting alternatives
Authors: Springer Johnny , Stone Kenneth R.
Published: February 2007

This paper summarizes the technologies and products for paint removal systems for aircraft, vehicles, and equipment, describing the mechanisms by which the technologies operate. The paper also discusses federal regulations that have had an impact on the development of technology in the area of coating removal. Pollution prevention assets and liabilities are presented for each technology and regulatory and other factors that will influence the future direction of coating removal technology development are discussed.
Using pollution prevention tools for compliance in the Federal community
Authors: Bridges James S. , Hoagland N. Theresa
Published: February 2007

In addition to environmental laws, Federal facilities must comply with Presidential Executive Orders, such as Executive Order 12856 which requires Federal facilities to put policies and practices in place in their environmental programs which emphasize pollution prevention as the alternative of “first choice” for how they will (1) achieve compliance with new regulations and requirements; (2) ensure compliance with existing regulations and requirements; and (3) return to compliance when violations are identified. This article identifies major environmental laws and executive orders affecting Federal facilities and presents demonstrated pollution prevention techniques and tools that will help Federal facilities with the environmental challenges while meeting mission objectives.
Development of a computer supported information system for measuring pollution prevention progress
Authors: Olbina Rada
Published: February 2007

The paper deals with the development of an information system for measuring pollution prevention progress at the industrial production facility level. The design of information systems is presented. Examples of information systems for solving of environmental problems are discussed. A framework of industrial production and waste generation system as a pollution prevention measuring system is outlined. A model of the system is presented and parameters are precisely defined. Cost analysis of the system is also carried out. Based on the model, an information system scheme for measuring pollution prevention progress is shown and its testing in an industrial production facility is discussed.
Environmental partnerships: Opportunities and challenges
Authors: Walton Thomas F.
Published: February 2007

Partenerships among business, government and environmental organizations show considerable promise for improving both the environment and the economic health of American business and industry. There is nothing more potent than a coalition of diverse interests. The author presents case studies based on his participation in partnerships involving General Motors (GM) and two environmental organizations. While environmental partnerships promise significant rewards, there are a number of challenges to be addressed, including entrenched adversarial attitudes and a regulatory paradigm that encourages business managers and government regulators alike to focus on paper “compliance” rather than real‐world performance. Overcoming these challenges will require that “win/lose” and “yes/no” be replaced by “win/win” and “how to.” It will require a new, market‐driven paradigm that fully integrates environmental considerations into the business planning process and that relies on economic incentives to encourage business managers and government regulators to seek out real solutions to real problems.
Development of a wastewater treatment process: Reductive dehalogenation of chlorinated hydrocarbons by metals
Authors: Schlimn Christian , Heitz Ewald
Published: February 2007

A low‐energy dechlorination technique has been applied to the detoxification of chlorinated hydrocarbons (CHCs) in aqeous solution. This alternative to biological or physco‐chemical decomposition methods achieves reduction by means of metal particles or copper‐activated metal particles (Mg, Fe, Al, Zn).

The paper presents data from two pilot studies, covering fundamental process design aspects. Experimental investigations of pilot study 1 were conducted in a laboratory‐scale fixed bed reactor. In weak acidic or neutral medium (pH‐range 4–7) proper process application resulted in very rapid removal of hexacholorocyclohexane concentration (γ – BHC, lindane) from model wastewaters with up to 99.3% efficiency. During the course of reaction the main products formed are chloride and benzene, the by‐product being small amounts of chlorobenzene. After employing different metals in the dechlorination reaction zinc proved to be the optimum reducing agent since it achieved the best space‐time yield. Pilot study 2 dealt with a couple of screening reactions of various CHCs with zinc as the reducing agent, which were performed in the batch mode. Even volatile CHCs (chloroform, 1, 1, 1‐trichloroethane) could be completely dechlorinated by forming the corresponding hydrocarbons (methane; ethane and ethene respectively). Pseudo‐first order rate constants (k, s−1) were determined to assess substrate reactivity with respect to possible process applications are discussed.
Reducing the leachable lead content of used oil filter paper
Authors: Gallup Darrell L.
Published: February 2007

Used automotive oil filter papers are typically contaminated with traces of lead and zinc particulates that may exceed the EPA toxicity characterization leaching procedure (TCLP) or the California soluble threshold limit concentration (STLC). The leachable lead and zinc content of oil filter paper may be reduced below hazardous waste levels by treatment with leach solutions comprised of metal complexing agents that dissolve a portion of the heavy metals. Further reduction of leachable lead and zinc in filter paper may be achieved by treatment with phosphate solutions to form insoluble metal phosphates. The resultant non‐toxic paper may be safely incinerated, while the leach “solubilizing” and phosphate “fixing” solutions are recycled. Lead and zinc are recovered from leach solutions by precipitation with sodium sulfide or polysulfide for beneficial use in lead/zinc smelter feedstock. The total levelized cost of treatment of filter paper to yield a non‐hazardous waste may range from $ 100–$ 300 per metric ton.
Biological elimination of VOCs in biofilter
Authors: Kiared K. , Bibeau L. , Brezezinski R. , Viel G. , Heitz M.
Published: February 2007

A laboratory scale biofilter system was used to eliminate toluene and ethanol, the main solvents employed in lacquering, from waste air. A specific micro‐flora (mixture of Bacillus for ethanol and two pseudomonas species for toluene) able to degrade ethanol and toluene, was fixed on a packed bed of particles of commercial peat intermittently humidified by a nutrient solution necessary for the survival of the micro‐organisms.

In the experiments, polluted gas was fed upwards through the bed and physcial parameters: moisture content of peat; humidity of air; temperature; pressure drop; inlet/outlet concentration of gas and microbial population were measured regularly in order to check the performance of the biodegradation process.

These experiments showed good performance and good stability of the biofilter over time.
Treatment of chlorinated ethenes in groundwater with ozone and hydrogen peroxide
Authors: Clancy Peter B. , Armstrong Jennifer , Couture Michelle , Lussky Robert , Wheeler Keith
Published: February 2007

A study was conducted to enhance the performance of an advanced oxidation process in treating chlorinated ethenes in groundwater at IBM's groundwater treatment system at its Essex Junction, Vermont facility. A model describing the reaction kinetics and mass transfer of a co‐current ozone injection process is presented. This model, in conjunction with experiments, demonstrates that the treatment performance of the ozone treatment process at a given ozone/air concentration and ozone mass flowrate cannot be improved by varying process operating parameters such as number of ozone injectors utilized, use of a static mixer, or variation of groundwater flowrate through each injector. This is because dissolved ozone reaches equilibrium with the injected ozone/air mixture within two seconds of initial contact. Also, the Venturi‐type ozone injection system presently in use destroys nearly half of the injected ozone.

Injection of hydrogen peroxide in conjunction with ozone increases the overall tetrachloroethylene (PCE) treatment efficiency by a factor of four (in comparison to ozone alone) at a H2O2/O3 mass ratio of between 1 and 2. Treatment of trichloroethylene (TCE) is enhanced by a factor of two. This enhancement of the oxidative treatment process results in a reduction in solvent mass load to a granular activated carbon (GAC) adsorption system located downstream, thus potentially reducing the usage GAC and regeneration of spent GAC. However, residual hydrogen peroxide and/or hydroxyl free radicals from the oxidation process effluent may interact adversely with certain grades of GAC; the causes of this interaction and methods to attenuate it (i.e., the use of more resistant grades of GAC) are discussed. Overall O3/H2O2/GAC system operating costs can potentially be reduced significantly (up to $ 20K annually). An economic analysis and system operation/cost optimization study are presented.
Use of Ambersorb® carbonaceous adsorbent for removal of BTEX compounds from oil‐field produced water
Authors: Gallup D. L. , Isacoff E. G. , Smith D. N.
Published: February 2007

The removal of high concentrations of BTEX compounds (benzene, toluene, ethylbenzene and xylenes) from oil‐field produced waters using a carbonaceous adsorbent was successfully demonstrated in the field. The carbonaceous adsorbent was much more effective in removing BTEX compounds from produced water than activated carbon or modified clays. The primary objectives of the field studies were to evaluate the efficiency of oil removal processes to protect the adsorbent from fouling, to determine the BTEX removal efficiency of a carbonaceous adsorbent at a high flow rate loading, and to demonstrate regeneration of the adsorbent.

Adsorbent fouling with oil was mitigated by mechanical coalescing for heavier crude and emulsion‐breaking for lighter crude. Adsorbent extenders and filters did not control fouling in the presence of exceedingly emulsified crude oil. Carbonaceous adsorbent reduced BTEX compounds levels from the 25–130 mg/l range to less than 1 mg/l treating approximately 500 bed volumes of produced water per cycle. Regeneration of the adsorbent using low pressure steam or solvents was successfully achieved with regeneration efficiencies exceeding 95 percent.
Life cycle assessment applied to process design: Environmental and economic analysis and optimization of a nitric acid plant
Authors: Kniel G. E. , Delmarco K. , Petrie J. G.
Published: February 2007

Life Cycle Assessment (LCA) is an environmental auditing tool that quantifies the environmental burdens of an activity inclusive of all its related systems. In the past, LCA has been applied primarily to products, but recent literature suggests it also has potential as an analysis and design tool for processes and services. This potential arises from the unique ability of LCA to link the environmental burdens of a process with its mass and energy flows. The aim of this work is to apply LCA as a tool for process design rather than one for product assessment. A nitric acid plant formed the basis for a case study wherein LCA was used to quantify and compare environmental performance of a number of design alternatives aimed at waste reduction. Economic models for the alternatives were formulated and linked to the environmental models to perform a multiobjective optimization with the express aim to maximize economic returns and minimize enviromental impact. The comparative study showed that one design alternative was clearly superior from an environmental point of view. The optimization demonstrated that operational changes could result in significant enviromental improvement at minimal economic cost. Future work in this area should focus on the allocation of environmental burdens from multiple‐output processes as well as extending the analysis to include environmental and economic impacts of all related downstream processes.
Air emissions of volatile liquids spilled on sands
Authors: Sharma Mukul , Overcamp Thomas J.
Published: February 2007

Simple laboratory experiments simulating a spill of a volatile liquid on sands were conducted. Hexane was spilled onto both initially dry sand and water‐wetted sand at near field capacity. The experimental conditions approximated the assumptions of a theory developed by Thibodeaux (1979). Predictions of a modification of this model were generally in good agreement at early times with data on the rate of volatilization. The modified model can be used to estimate air emissions of a volatile liquid spilled on sands.
Process challenges in rotary kiln‐based incinerators in soil remediation projects
Authors: Acharya Prakash , Fogo Denis , McBride Chris
Published: February 2007

Most Superfund sites undergoing thermal remediation consist of high‐moisture content (15 to 40 percent) soils having light organic contamination (low‐heat content). In the early 1980s, the rotary kiln incinerators employed at these Superfund sites were relatively small mobile hazardous waste incinerators (HWI) built on standard‐size semi‐trailers. As the industry matured over the past ten years, competition has driven the industry to larger and more efficient rotary kiln systems that minimize the cost per ton of soil treated by increasing the throughput rates and shortening on‐site processing time.

Because these units are transported from site to site by truck or a combination of rail and truck, the rotary kiln outside shell diameters have peaked to approximately 13.5 feet. Now the focus has shifted to increasing the processing capacity of these existing, maximized fixed‐sized systems. Such actions include the use of oxygen‐based combustion systems, which increase the throughput and efficiency by improving heat transfer and reducing the volume of combustion gas requiring treatment. However, despite the experience and expertise gained by the participants in the thermal remediation industry, many of the same process challenges still remain. Combustion gas particulate entrainment from a rotary kiln HWI is a key issue when thermally treating soils because of the slagging potential in the secondary combustion chamber (SCC) and/or the potential to overload the downstream incinerator wastewater treatment system (IWTS). Excessive infiltration air into the rotary kiln can reduce the rate of heat transfer to the solids bed and correspondingly reduce the overall processing rate. More stringent ash quality requirements require higher ash temperatures and longer solids retention time at temperature. Estimating metal emissions remains a challenge due to the limited availability of data on metal behavior in combustion systems. New and more stringent particulate, nitrogen oxides (NOx), metals, and dioxins/furans emissions performance requirements present additional challenges, as does a trend in towards zero‐liquid discharge from the air pollution control system.

This article discusses these process challenges facing the industry and potential solutions, based on data from IT's Hybrid Thermal Treatment System® HTTS® and other sources.
Surmounting design problems in a complex piping system for groundwater remediation
Authors: Maxey Robert , Pincince Richard
Published: February 2007

This paper describes the design of a fiberglass reinforced plastic (FRP) piping system which transports groundwater extracted from 43 wells at the site of a former chemical manufacturing plant in Toms River, New Jersey. This system conveys an average flow of 2.7 million gallons per day of groundwater contaminated with aromatics, chlorinated hydrocarbons and metals through seven miles of pipeline to a biological and physical treatment plant. The piping system, shown in Figure 1 exceeds the scale typically seen in most groundwater remediation projects, with respect to length, number of wells and volume of water treated.

The groundwater extraction system is a manifold piping network that consists of the 43 wells and associated pumps, piping and controls and is capable of conveying 150% of the average flow. All piping within plant boundaries is above ground. Offsite piping is installed below ground and is double walled. Leak detection devices are installed below ground in manways along the buried pipe route. Discharge piping from well pumps is tied into manifolds which go to the groundwater treatment plant.

This paper describes design choices significantly affecting the system construction, piping system components, design procedures and significant lessons learned in the construction of the system. System design commenced in 1993, was completed in 1995 and system construction was finished in 1996.
The magnitude and source of air emissions from asphalt blowing operations
Authors: Trumbore David C.
Published: February 2007

The US EPA has developed emmission factors for estimating the emissions of filterable particulate, total organic compounds, and carbon monoxide from asphalt blowing operations. These are published by the EPA in a series called AP‐42, which contain factors for many manufacturing processes. The emission factors for asphalt blowing are acknowledged by the EPA to be of poor quality. Owens Corning has taken extensive data in various manufacturing facilities and an asphalt pilot plant to provide more information on air emissions from these operations. The results of that work clearly show that the current AP‐42 emission factors for asphalt processed by air blowing are dificient in that they omit significant emissions of SOx and HCl, overestimate particulate and CO emissions, and potentially underestimate both VOC and NOx emissions. In fact, SOx, which is not addressed by AP‐42, is the major air emission contributed by the fumes from the asphalt blowing process when those fumes are incinerated. The sources of SOx from air blowing are discussed in detail in this paper. The impact of incineration temperature on carbon monoxide is also illustrated. With the exception of HCl, the hazardous air pollutants encountered in the asphalt blowing process are minimal.
A sorbent regenerator simulation model in copper oxide flue gas cleanup processes
Authors: Chen Zhong‐Ying , Yeh James T.
Published: February 2007

Sorbent regeneration is an important step in copper oxide flue gas cleanup processes because poor regeneration performance could require higher sorbent circulation rate and inventory, resulting in increased process costs. This article describes a countercurrent moving‐bed regeneator model using natural gas as the reducing agent. The model incorporates several aspects important for predicting the regenerator performance, such as gas expansion effects, deviation from first‐order kinetics with respect to copper sulfate, and mass transfer limitations. The sorbent residence time predicted by this model is in good agreement with data obtained from the life‐cycle test system at the Federal Energy Technology Center. The tests conducted include effects of reactor temperature, the methane to copper sulfate feed ratio, and sorbent residence time, on sorbent regeneration. The regenerator modeling also details the impact of gas velocity on the reactor performance.
The effect of oxygen exposure on the methanogenic activity of an anaerobic bacterial consortium
Authors: Petersen James N. , Bereded‐Samuel Yared , Skeen Rodney S.
Published: February 2007

Due to industrial, agricultural, and defense operations, chlorinated solvents, and their natural transformation products, have been found in drinking water, wastewater, and ground water throughout the industrialized world [1]. Further, such compounds represent the most prevalent organic groundwater contaminants in the U.S. [2]. Because many are priority pollutants and/or suspected carcinogens or mutagens, the movement, transformation, and fate of these contaminants in the environment is of interest [3]. For these compounds, in situ bioremediation has the potential to substantially reduce cleanup duration and cost, when compared with traditional pump‐and‐treat technologies [4].
Science plus management equals successful remediation: A case study
Authors: Buehlman Mark D. , Rogers Daniel T. , Payne Frederick C.
Published: February 2007

In the past, owners of contaminated sites attempted to remediate as quickly as possible, usually by excavating contaminated soil or pumping and treating contaminated groundwater. Often, they started remediation before identifying all potential types and sources of contaminants, and before conducting a thorough hydrogeologic study. Such premature action usually resulted in the selected remedy not working, the contamination spreading, or unnecessary remedial activities. Today, successful site remediation is recognized as a complex and time‐consuming undertaking–requiring a combination of careful scientific study, effective negotiation with the regulatory agencies and skillful management of multidisciplinary efforts.

A case study involving a brownfields site in southeastern Michigan clearly illustrates the elements of successful remediation. The site's soil was contaminated with polychlorinated biphenyls (PCBs) and its groundwater with a variety of chlorinated solvents. The original estimate for remediation had exceeded $30 million. Several phases of investigation were conducted to evaluate the nature and sources of contaminants, the site's hydrogeology, potential risks to human health and the environment, and feasible remedial technologies. Multiple cleanup criteria were established for different affected areas based on the results of the investigations, changes that were taking place with the state cleanup regulations and standards and subsequent negotiations with state and federal regulators. Innovative remedial technologies were selected. The result was a remediation that met or exceeded all soil and groundwater cleanup objectives, was performed on schedule, and was highly cost‐effective. The final cost was limited to $3 million–one‐tenth of the original estimate.

The success of this project involved meticulous scientific study and comprehensive understanding of applicable regulatory requirements and available remediation technologies. It also required effective project management to coordinate the multidisciplinary efforts involved and to maintain the constant vertical and horizontal communications necessary to ensure sound decisions at every step in the process.
Precipitation and separation of chloride and sulfate ions from aqueous solutions: Basic experimental performance and modelling
Authors: Bader M. S. H.
Published: February 2007

An experimental database for the precipitation of chloride and sulfate salts associated with six cations (sodium, potassium, magnesium, calcium, barium, and strontium) from aqueous solutions was generated using isopropylamine as the precipitation agent. Consistency tests performed on the acquired precipitation data indicated a high level of experimental consistency. The precipitation fractions (P) of all chloride salts (at 5,000 and 10,000 mg/L) over the studied range of solvents volume ratios (VR) were approximately identical and their small variations were within their experimental uncertainty. The P of sulfate salts (1,000 mg/L) over the studied range of VR were appreciably varied.

A framework derived from thermodynamic principles of liquid‐liquid equilibrium criteria was developed to correlate the precipitation data. The activity coefficient of a given salt in a reference solvent (water) was related to the activity coefficient of such a salt in a mixed‐solvent mixture (water and organic). The power series function was employed to express the activity coefficients. Two model equations were provided by the framework: the 2‐power equation with two interaction parameters, and the 3‐power equation with three interaction parameters. While both equations were adequate for correlating the solubility phase behavior of a salt in a mixed‐solvent mixture, the 3‐power equation was more accurate.
Membrane separation processes for clean production
Authors: Paul D. , Ohlrogge K.
Published: February 2007

Clean production can be considered as a strategic element in manufacturing technology for present and future products in the chemical industry. Demand is focussed on the development of cost‐effective technologies, the optimization of processes including separation steps, alternative processes for the reduction of waste, optimization of the use of resource and improvements in production efficiency. In many cases an environmentally friendly alternative to conventional separation processes could be membrane separation. Membrane separation techniques are suitable for mixtures of liquids, gases and vapors. Some examples of successful applications in the areas of waste water treatment and vapor recovery are given. Demands, advantages and problems of separation with membranes are also discussed.
Corona‐induced chemical scrubber for the control of NOx emissions
Authors: Yang Chen‐Lu , Beltran Michael , Kravets Zhorzh , Yamamoto Toshiaki
Published: February 2007

Two dielectric materials (barium titanate and glass pellets) were evaluated for their ability to decompose/oxidize nitric oxide (NO) by nonthermal plasma discharge. Both barium titanate and glass pellets were tested in a packed bed dielectric barrier plasma reactor. The plasma reactor using barium, titanate completely destroys 130 ppm of NO in an air stream at an electric field strength of 9 kV/cm. A majority of the incoming NO is decomposed to N2 and O2. However, 30% of the NO is oxidized to NO2. The plasma reactor using glass pellets in a similar system is just as effective, but at a 3 k V/cm higher electric field strength. The 40 ppm NO2 in the effluent of the plasma reactor is then removed quantitatively by a caustic sodium sulfite aqueous scrubbing system. The outlet concentrations of both NO and NO2 from the plasma‐scrubber combination system (corona‐induced chemical scrubber) are beyond the detection limit of the chemiluminescent NOx analyzer.
Characterization, decontamination and health effects of fly ash from waste incinerators
Authors: Lee P. H. , Delay I. , Nasserzadeh V. , Swithenbank J. , McLeod C. , Argent B. B. , Goodfellow J.
Published: February 2007

The aims of the present work are (a) to investigate the physical and chemical properties of incinerator ash which are of importance for its utilization and environmental impact; (b) to evaluate the occupational exposure of incinerator workers to trace metals; and (c) to develop a novel technology for the conversion of contaminated fly‐ash from incinerators into a material which can be disposed of cheaply or used in the construction industry. The discussion is illustrated by results obtained through experiments.

Morphologically, fly‐ash consists of irregularly shaped material, of widely varying sizes. Some minerals are identified using powder X‐ray diffraction, i.e. calcite, pyrite, halite and maghemite. The chemical composition of ash samples examined consist of Ca, Al, Si, K, Ti, Mg, Fe, K, Na and Mn as the major and minor elements. Trace elements such as Pb, Co, Cr, Ni, Cu, Se, Mo and Cd are also found. The samples tested are rich in Cl, Cr, Zn, Sn and Pb, as compared to the earth's crust values. About 50% of the fly‐ash particles are smaller than 5.5 μm. These particles can play an important role in transferring toxic metals into the human blood stream by inhalation, deposition and absorption. The ash is reported as having medium fusibility, with softening between 1220°C and 1250°C due to it's pyrite content. This is most likely to give clinker problems and affect the sintering process of fly‐ash. The detoxification approach is based on the fact that sintering or melting of this ash results in the destruction of its toxic organic components, including fixation of its heavy metal content to form an unleachable material which can be landfilled or used for building roads. A key aspect of this work is the technique used to ensure the energy efficiency of the sintering/melting process which is based on the application of a regenerative heating concept. The conclusions of the research are expected to have a major impact on future codes of practice and standards for dealing with contaminated fly‐ash.