bluuebunny/crossref_metadata_2025 huggingface dataset:
Wet gas scrubbing: State of the art in FCCU emission control
Authors: Cunic J. D. , Bienstock M. G. , Edelman A. M.
Published: February 2007

Particulates and SO2 in Fluid Catalytic Cracking Unit (FCCU) flue gas can be controlled via wet gas scrubbing. Wet Gas Scrubbers (WGS) are compatible with the gaseous emission control devices such as CO boilers or High Temperature Regeneration (HTR) now in use on FCCU's and require no changes in FCCU operating procedures. Compared with a combination of particulate control with electrostatic precipitators and SO2 control by FCCU feed desulfurization, WGS require less investment and have lower operating costs. Other advantages for WGS include higher service factor, smaller onsite plot space requirement, and simpler operation than electrostatic precipitators.

Purged scrubber liquid must be treated by conventional waste water treatment technology to reduce suspended solids and COD. Even after such treatment, the purge stream will still contain dissolved solids. However, at many locations, the disposal of the purge stream can be accommodated without adverse environmental problems. Four commercial scrubbers, now in operation in Exxon Company, U.S.A. refineries, reduce particulate emissions to compliance levels with all pertinent regulations. SO2 removals are in excess of 90%. Currently, four licensee companies are also applying the Exxon scrubbing process. More are anticipated. These commercial units have accumulated over 64 years of combined operations (as of February 1, 1987).
Adsorptive capacities of activated carbon for organic constituents of wastewaters
Authors: Ying Wei‐chi , Dietz Edward A. , Woehr George C.
Published: February 2007

The adsorptive capacities of activated carbon for major organic constituents (target compounds) of a wide variety of wastewater were measured in pure water and in actual wastewater samples. Competitive adsorption due to the presence of other orgnic components of total organic carbon of the wastewater (background TOC) reduced carbon capacities for all target compounds in the wastewaters from the respective pure water isotherms. The capacity reduction for a target compound was found to depend on the relative adsorptivity of the target compound versus competing compounds (poorly adsorbed TOC components produced a small reduction in capacity for a more strongly adsorbed target compound), and the fraction of the background TOC attributable to the target compound. Those findings were validated by carbon column adsorption breakthrough data.
Gas reburning‐sorbent injection for controlling SOx and NOx in utility boilers
Authors: Bartok W. , Folsom B. A. , Elbl M. , Kurzynske F. R. , Ritz H. J.
Published: February 2007

As part of DOE's Clean Coal Technology program, a field evaluation of Gas Reburning‐Sorbent Injection (GR‐SI) technology is being carried out by Energy and Environmental Research Corporation. The project is cofunded by the Gas Research Institute and the State of Illinois Department of Energy and Natural Resources. GR‐SI technology is applicable to the control of emissions of acid rain precursor species, oxides of nitrogen and sulfur from coal fired utility boilers. Three units representative of pre‐NSPS design practices, a 117 MWe wall, a 71 MWe tangentially, and a 33 MWe cyclone fired boiler located in Illinois will be the host sites for this three‐phase demonstration project.

Process specification studies have confirmed that GR‐SI technology is capable of achieving the stated goals of the project, 60 percent reduction in NOx and 50 percent reduction in SO2 emissions. NOx emissions will be reduced by staged fuel addition using natural gas as the reburn fuel, while SO2 emissions will be reduced by capturing sulfur by dry, calcium based sorbent injection which will be augmented by the displacement of about 15–20 percent of the coal input by natural gas firing.

Phase 1, Design and Permitting, was completed earlier this year. In addition to process specifications which focused on injection system design criteria and precipitator enhancement approaches, detailed environmental information has been developed, including the assessment of waste disposal options and performing permitting work. In phase 2 of the project, anticipated to be initiated in 1989, installation and check‐out will be performed. The project will culminate in sustained 12‐month demonstrations of the technology on each host unit. Results of Phase 1 and plans for subsequent work will be discussed.
EPA's assessment of European contaminated soil treatment techniques
Authors: Pheiffer Thomas H. , Nunno Thomas J. , Walters Janette S.
Published: February 2007

Site remediation is a pressing issue in European countries due to limited availability of land. Therefore, much progress is being made in the development of effective technologies for remediating contaminated sites. The purpose of the program described in this paper was to investigate the most successful and innovative European technologies for potential introduction into U.S. markets. Phase I of this EPA–sponsored project was a 9‐month research effort which identified 95 innovative technologies in use or being researched in foreign countries. During Phase II, the most promising technologies identified in Phase I were studied in–depth through personal interviews with the engineers who research and apply these technologies, and through tours of laboratory models and full–scale installations. Phase III of the assessment effort culminated in the first forum on innovative domestic and international hazardous waste treatment technologies on June 19–21, 1989, in Atlanta, Georgia. The most successful full–scale technologies investigated were developed in the Netherlands and West Germany. These technologies include vacuum extraction of hydrocarbons from soil, in situ washing of cadmium‐polluted soil, in situ steam stripping, and a number of landfarming and soil washing operations. The paper provides description of 11 soil remediation techniques that have shown such promise in laboratory studies or in practice to warrant consideration of their use in the United States, and summary information on the international technologies selected for presentation at the Phase III forum as they relate to soils remediation.
Estimation of multimedia environmental contamination of 2,3,7,8‐TCDD emissions from municipal waste incinerators
Authors: Hwang Steve T.
Published: February 2007

2,3,7,8‐tetrachlorodibenzo–p–dioxin (2,3,7,8–TCDD) is known to be most toxic among congeners of polychlorinated dibenzo–p–dioxins (CDD), and is known to cause cancer to humans upon prolonged exposure—even at extremely low dosag. The municipal waste incinerator is one of the combustion devices where literature test result have shown the presence of 2,3,7,8‐TCDD or CDDs in flue gas or ash. A recent report compiled by the U.S. Environmental Protection Agency [13] also lists other combustion devices such as smelters, sewage sludge incinerators, wire reclamation incinerators, and drum and barrel furnaces. In addition, Sheffield [11] mentions forest fires and several types of chemical production facilities as sources. Des rosier and Lee [2] cite PCB transformer fires as a potential source of 2,3,7,8–TCDD formation. The primary focus of this paper is to present the potential of environmental contamination due to emissions of 2,3,7,8‐TCDD and disposal of fly ash generated from the incineration of municipal waste. Example assessments for municipal incinerators presented in this paper are based on presently available estimation techniques and hence represent estimates for environmental concentrations. exposures and health risks. Although actual emission data are used, uncertainties associated with the estimates cannot be fully assessed until these estimates are compared with some monitoring data, especially concerning environmental concentrations related to indirect exposure pathways.
PCB detoxification technologies: A critical assessment
Authors: Woodyard John P.
Published: February 2007

Management of PCBs under the Toxic Substances Control Act (TSCA) since promulgation of the first regulations in 1978 has cost industry and government over $1 billion. A significant portion of that expense has been associated with disposal of PCB liquids and PCB articles, ranging from routine PCB removal and replacement to disposal of debris from PCB spills and fires.

Since the first PCB incineration permit was granted by the U.S. EPA in 1979, PCBs have also been one of the most expensive chemicals to dispose of commercially. High prices combined with the limited permitted disposal capacity has prompted scientists and engineers to continue the search for less expensive ways to detoxify PCB‐contaminated material. Ironically, these factors have also driven the development of innovative technology for other less expensive waste streams that would otherwise have been passed over.

The search for improved PCB detoxification technology continues as disposal capacity continues to shrink and PCB–related cleanups approach the remediation stage. This paper looks at the state of PCB detoxification technology, reviewing past and present technology development efforts and relating these technologies to the industry's remedial needs in the coming years.
Minimization of chromium‐contaminated wastewater at a plating facility in the Eastern United States
Authors: Walker J. F. , Wilson J. H. , Brown C. H.
Published: February 2007

The Oak Ridge National Laboratory (ORNL) is conducting a hazardous waste minimization program at an industrial plating facility located in the Eastern United States. A. Detailed investigation of the existing facility was conducted by ORNL which indicated that chromium was the major source of contamination. Several improvements in the operation of the facility were implemented which reduced the quantity of chromium lost from the facility by ∼85%. The remaining chromium–Contaminated wastewater streams will be treated by reverse osmosis (RO) followed by evaporation of the RO concentrate for further volume reduction. This paper discusses (1) the plating shop modifications which resulted in an 85% reduction of the quantity of chromium contamination exiting the plating facility, (2) the results of RO pilot–scale tests, and (3) start up of the full–scale RO/evaporator system the plating facility.
Removal of organics from offshore produced waters using nanofiltration membrane technology
Authors: Dyke Charles A. , Bartels Craig R.
Published: February 2007

The separation of oil and produced water mixtures from oil and gas producing wells has traditionally been accomplished by gravity settlers (e.g., multi‐phase separators, skimmers, and flotation cells). However, current EPA regulations on the organic content of discharged produced water have reached the limits of these separation techniques. The industry is in need of new technologies to treat these waters. One such technology that we have found promissing is organics/water separation by nanofiltration membranes.
Design considerations for soil cleanup by soil vapor extraction
Authors: Ball Raymond , Wolf Steve
Published: February 2007

The development and application of innovative technologies for soil remediation is rapidly evolving. Soil vapor extraction has been identified as one of the most attractive technologies for remediating volatile organic compounds in unsaturated zone (above the groundwater table) soil, because it is effective and economical. However, the design basis for applying this technology is not well documented. This paper presents a state‐of‐the‐art approach for design and implementation of a soil vapor extraction system to remediate soil at a federal site in the Midwest contaminated with tetrachloroethylene.
The effect of oxidants on UV destruction of chlorophenols
Authors: Ku Young , Ho Shu‐Chu
Published: February 2007

Ultraviolet treatment is used for the destruction of refractory wastewater components. This paper addressed its application on the destruction of nonbiodegradable chlorophenols with the presence of different oxidants. The experiments were carried out in a batch photoreactor under various pH, dissolved oxygen (DO) time, and oxidant types and concentrations. Experimental result indicates that the dissolved oxygen levels has little effect on the destruction of chlorophenols by UV irradiation. The presence of some oxidants (e.g., H2O2) significantly increases the destruction efficiencies of chlorophenols by UV treatment. The reaction kinetics are studied and discussed. Proper reactor design is essential to the successful application of UV/oxidant treatment.
The incineration system “Thermal siphon” effect
Authors: Kroll Peter J. , Chang Robert C.
Published: February 2007

An anomalous phenomenon known as the “thermal siphon” effect has been observed in four operational incinerators with vertical secondary combustion chambers (SCCs). The kiln and air pollution control (APC) system pressures in all four cases have, under certain conditons, been observed to be negative while the pressure at the top of the SCC is positive. This paper will focus on an explanation of this unusual fluid flow phenomenon.
RBC nitrification of high ammonia leachates
Authors: Opatken Edward J. , Bond James J.
Published: February 2007

A study was conducted on treating a simulated leachate that contained high concentrations of ammonia‐nitrogen ranging between 20 and 1000 mg/L. A pilot sized rotating biological contractor (RBC) was used to treat a surrogate leachate composed of primary effluent that was adjusted with glucose and ammonium chloride to achieve various concentrations of dissolved organic carbon (DOC) and ammonia‐nitrogen. Experiments were conducted to determine:

The rate of ammonia conversion

The drop in pH at high ammonia concentrations

The effect of low pH on ammonia conversion

The effect of high ammonia levels (1000 mg/L) on ammonia conversion

The effect of temperature on the reaction rate constant The results from these experiments and the applicability of a RBC to treat leachates containing high concentrations of ammonia‐nitrogen are reported.
MIN‐CYANIDE: An expert system for cyanide waste minimization in electroplating plants
Authors: Huang Y. L. , Sundar G. , Fan L. T.
Published: February 2007

Rapid development of technologies and production systems is often accompanied by the increased generation of hazardous or toxic wastes. Among these wastes, waste solutions containing cyanide cause a particularly serious problem, threatening both public health and environment. It appears that the best way to minimize the cyanide‐containing wastes is to reduce their production in electroplating plants. Numerous techniques have been developed for this purpose, and much experience has been gained by applying such techniques. An expert system, MIN‐CYANIDE, has been constructed to assist engineers and technicians in the source reduction of cyanide‐waste solutions in an electroplating plant by resorting to these techniques and experience, and to train plant operators in the application of the techniques. MIN‐CYANIDE evaluates options, such as dragout minimization, bath‐life extension, rinse‐water reduction, replacement with a non‐cyanide solution, use of an alternative plating technique, and improvement of the operating procedure; furthermore, it identifies the most effective among them. The knowledge about the cyanide source reduction is acquired from available publications, represented by numerous fuzzy or non‐fuzzy heuristic rules, and codified into a commercial export system shell, Personal Consultant Plus, on an IBM PC/AT compatible computer. MIN‐CYANIDE provides a userfriendly interface; in operating it, the user answers various questions concerning the operational situations of the production and/or current equipment and techniques in the plant. In response, MIN‐CYANIDE will present instantaneously a series of options for cyanide minimization and eventually rank them.
Field verification of predictive modeling of organic compound removal by biological wastewater treatment processes
Authors: Barton Douglas A. , McKeown James J.
Published: February 2007

This paper presents the results of a field study conducted to examine the accuracy achieved when modeling the removal of organic compounds by biological wastewater treatment processes. Special emphasis is placed on determining the specific removal pathway, accuracy for three compounds, believed to the removed primarily by only one pathway. Off‐gas chloroform measurements made through use of a surface isolation flux chamber were modeled to within two percent, as were measurements reflecting the biodegradative removal of methanol. Varying degrees of accuracy were obtained for the chlorophenolic compounds examined.
Competivive sorption of benzene, toluene and the xylenes onto soil
Authors: Stuart B. J. , Bowlen G. F. , Kosson D. S.
Published: February 2007

Knowledge of contaminant soil‐groundwater partitioning is of crucial importance in determining contaminant transport. The majority of studis to date examine only single contaminant partitioning. Studies presented in this paper investigated single contaminant and multiple, competitive contaminant partitioning of benzene, toluene, and xylenes with a sandy loam soil. Batch serum bottle and flow soil column studies were utilized. Significant competitive effects were observed.
Biological process design and pilot testing for a carbon oxidation, nitrification, and denitrification system
Authors: Givens Silas W. , Brown Eric V. , Gelman Steven R. , Grady C. P. Leslie , Skedsvold Daniel A.
Published: February 2007

In response to a new NPDES permit incorporating Organic Chemical, Plastic, and Synthetic Fiber (OCPSF) effluent limits for BOD (carbonaceous and nitrogenous), TSS, and priority pollutants, a treatability study was conducted to establish design criteria for a new process wastewater treatment plant for DSM Chemicals North America, Inc. The permit also requires partial removal of total nitrogen. Based on the discharge criteria, a two‐stage biological process configuration was selected. The configuration consisted of an anoxic followed by an aerobic reactor with mixed liquor recirculation. To establish design criteria, a two‐phase study was conducted. The first phase involved determining wastewater characteristics and kinetic and stoichiometric coefficients. These values were used as input to “Simulation of Single‐Sludge Processes” (SSSP), a computer model that was used to evaluate potential process configurations. In the second phase, a pilot‐scale system was operated to verify performance. With a volume distribution of 40 percent anoxic and 60 percent aerobic and a recirculation ratio of 2, BOD, COD, and total nitrogen removal efficiencies of 99, 88, and 80 percent were obtained, respectively. Approximately 84 percent of the biodegradable COD was removed through denitrification.
Bioreactor design effects on biodegradation capabilities of VOCs in wastewater
Authors: Hill G. A. , Tomusiak M. E. , Quail B. , Van Cleave K. M.
Published: February 2007

Volatile organic chemicals are a wastewater pollution problem that can be handled by ultrafiltration, stripping, or biodegradation. Ultrafiltration and stripping transfer the dissolved organics to another phase which should then be further treated to finally destroy or utilize the organic chemicals. Biodegradation, on the other hand, converts the water soluble molecules to bio‐molecules which can then be separated or directly discharged. Biodegradation of aromatic chemicals requires air and tests have conclusively shown that traditional biodegradation designs result in VOC stripping losses to the air stream rather than biodegradation.

Computer models and experimental data are presented comparing batch (plug flow), CSTR and packed bed bioreactor designs for their abilities to degrade VOC chemicals. Batch or plug flow reactors are shown to be a very poor method for biodegradation. CSTRs work well but require a large process residence time.

A new packed bed column bioractor will be shown to provide much faster biodegradation and still minimize air stripping losses. Mass transfer and fluid mechanic parameters have been measured with and without biomass and compared to traditional chemical engineering correlations. The packed column minimizes the demand for air flow while increasing the throughput rate of wastewater as compared to a CSTR design. The efficiency of VOC biodegradation will be seen to be greatly improved.
Temperature profile and heat transfer model for a chemical wastewater treatment plant
Authors: Brown Eric V. , Enzminger Jeffrey D.
Published: February 2007

This paper presents a heat transfer model for equalization, activated sludge, and trickling filter unit processes that can be used to assess the effect of operating temperature on unit process selection, materials of construction selection, and heat retention and cooling requirements. In developing this model, the individual variables that affect the operating temperature of biological systems were first identified. Mathematical relationships were then developed to described system behavior, based on conservation laws and rate equations. The heat transfer models were then used to develop a temperature profile of the two alternative WWTP configurations.
Advanced non‐catalytic post combustion NOx control
Authors: Chen S. L. , Lyon R. K. , Seeker W. R.
Published: February 2007

The effectiveness of combustion modifications, including staged combustion and reburning, for the control of nitrogen oxide emissions from coal or oil fired combustors is most often limited by problems due to carbon burnout or flame impingement. This paper presents new data on the use of selective reducing agents, such as ammonium sulfate, suggesting that a hybrid control scheme is possible which uses combustion modification to provide those conditions which optimize the selective reduction process. Very low emission levels appear possible that can presently only be achieved by catalytic reduction.
The direct sulfur recovery process
Authors: Gangwal Santosh K. , McMichael William J. , Dorchak Thomas P.
Published: February 2007

The Research Triangle Institute under contract to the U.S. Department of Energy, Morgantown Energy Technology Center, is developing the Direct Sulfur Recovery Process (DSRP) for converting either reduced or oxidized sulfur gases directly to elemental sulfur. Laboratory tests were conducted to evaluate the effects of stoichiometry, pressure, temperature, space velocity and steam content. Pressure was found to be the most important variable. Increasing pressure from 1.5 atm to 20 atm quadrupled the sulfur recovery at equivalent space velocity. Sulfur recoveries from dilute SO2 streams were greater than 96% in tests simulating the first stage of reaction. In the first stage of reaction, SO2 is directly reduced to elemental sulfur by coal gas or other reducing gases at high temperature and high pressure. Under second‐stage reaction conditions, recoveries ranged from 80 to 98% depending on operating conditions. Combined with a first‐stage conversion of 96%, this translates into overall conversions of 99.2 to 99.9%. Preliminary economic comparisons with conventional processes that could be used for treating dilute SO2 tail gases showed a decisive cost advantage for the new catalytic process. The effectiveness of the high‐pressure, high‐temperature DSRP on H2S containing gases has also been demonstrated. Direct conversions of H2S to elemental sulfur ranged to 98% in a single stage of reaction using near stoichiometric amounts of air or oxygen. Bench‐scale development is ongoing to investigate a variety of reactor types and configurations.
Full‐scale remediation of a grey iron foundry waste surface impoundment
Authors: Krueger Richard C. , Chowdhury Ajit K. , Warner Michael A.
Published: February 2007

A large grey iron foundry was facing remediation of a surface impoundment containing approximately 300,000 cubic yards of EP‐Toxic sludge. The sludge was generated by the settling of wastewater solids from air emission control systems connected with cupola melting operations. Bench‐scale treatability testing was used to evaluate various chemical treatment possibilities for rendering the sludge non‐EP‐Toxic. Several phosphate sources and different engineering options were evaluated for cost‐effectiveness of full‐scale remediation. The most economical option was to dredge the solids continuously as a slurry (while the impoundment remained in operation) with injection of phosphoric acid into the slurry pipeline. The treatment process was controlled by monitoring residual phosphate in the treated slurry. The remediation process was tested in a month‐long field trial using full‐scale equipment, and was followed by successful remediation during a 6‐month period. A technical overview and performance data on the remediation process are presented.
Selection of treatment process to meet OCPSF limitations
Authors: Friday Thomas L. , Gupta Rakesh
Published: February 2007

Allied‐Signal manufactures phenol, a precursor for nylon 6, at its plant in Philadelphia, Pennsylvania. During this process wastewater is generated which is discharged to a POTW (Publicly Owned Treatment Works). The wastewater discharged has to meet the Organic Chemicals, Plastics, and Synthetic Fibers (OCPSF) pretreatment standard as defined as defined in the U.S. EPA regulation 40 CFR 414.

In order to reduce concentrations of the various waste products, several technologies were evaluated including biological treatment, UV oxidation, and air stripping. Air stripping (or desorption) was initially rejected because it could not remove phenol to the desired level. Phenol has a low volatility which makes it difficult to strip. During the regulatory process, phenol was remanded from the list of OCPSF regulated chemicals. Therefore, air stripping was reevaluated as a treatment alternative. Additional studies showed that air stripping was the most cost effective method for removal of the regulated chemicals as well as a large percentage of the other volatile constituents. A thermal oxidizer was selected to destroy the organic compounds in the vapor stream from the air stripper column.

Pilot studies were conducted to confirm literature values for the mass transfer coefficient of the components. The pilot data were then used to size the full scale stripper.

The thermal oxidizer was designed using previous experinece with handling similar compounds. Because of the high flow rates, heat recovery was added to minimize fuel cost. The equipment selection was based on cost effectiveness.

The paper will discuss the various issues encountered during the selection of the treatment process.
Computerized batch process for treating electroplating wastes
Authors: Reisser Arye , Lewin Daniel R.
Published: February 2007

The application of batch processing to the treatment of electroplating wastes is described. The previously used continuous process proved to be unsatisfactory because of difficult and varying operating conditions over the treatment cycle and varying electroplating formulations. Consequently, a batch process was selected because of it is inherent advantageous in such cases. This study presents the reasoning behind this decision and describes the process and design factors that led to the particular facility.
Treatment of contaminated water, air and soil with UV flashlamps
Authors: Wekhof Alex
Published: February 2007

A new and effective method has been developed for the treatment of VOC's, PCB's and other toxic organics. Direct UV photolysis of organics is achieved with this new method with the use of high intensity ultraviolet light of a broad UV spectrum. Standard and novel UV flashlamps can be used for generation of this broad UV spectrum. The pulsing nature of such spectrum helps to increase the efficiency of destruction of toxics. The final products of this destruction process are non‐toxic simple compounds. The energy efficiency of this new process exceeds that of traditional UV aided processes with medium pressure mercury lamps. This article reviews the Direct UV Photolysis Process, gives experimental results, and provides recommendations for applications in the treatment of groundwater, wastewater, contaminated air and soil.
A research institute wastewater treatment program
Authors: Nyuk‐Min Chong , Duen‐Gang Mou
Published: February 2007

A research institute, due to its routine use of chemicals, equipment, and energy in research activities, is without exception a waste generator. The Development Center for Biotechnology in Taiwan, the Republic of China, has therfore taken the initiative in constructing an up‐to‐date plant for the treatment of liquid wastes in consideration of the public concerns and environmental impact. From the start operation of the wastewater treatment plant in July, 1989, the effuent quality has been maintained, at one hundred percent of the time, lower than the effluent discharge limits. The gained operation experiences as well as qualitative and quantitative aspects of liquid waste outputs from the biotechnology research institute are presented.
Influence of different additives on the reaction between hydrated lime and sulfur dioxide
Authors: Cunill Fidel , Izquierdo José F. , Martínez Juan C. , Tejero Javier , Querol Javier
Published: February 2007

Five commercial calcium hydroxides were tested in a fixed‐bed reactor for SO2 removal at bag‐filter conditions. Small amounts of different additives (fly ash, NaOH, NaCl and CaCl2) were added to the commercial Ca(OH)2 which showed the greatest reactivity respect to SO2 (by a drying process). Fly ash performance was negative whereas the rest of additives enhanced the desulfurization power of the Ca(OH)2, specially NaOH (due to its basic and deliquescent character) and CaCl2 (by its delilquescence). CaCl2 has been the best additive tested at the used experimental conditions.
Recovery of gallium and arsenic from GaAs wafer manufacturing slurries
Authors: Jadvar Reza , McCoy Benjamin J. , Ford Bill , Galt Jerry
Published: February 2007

Lapping and polishing slurries from the gallium arsenide (GaAs) wafer manufacturing process were used to develop simple and inexpensive methods for separation and recovery of valuable gallium and toxic arsenic. The lapping slurry, containing GaAs, glycerol, alumina, iron oxide, and water, is treated by a process involving water addition, dissolution of GaAs, mixing, sedimentation, decantation, and evaporation. The polishing slurry, containing GaAs, silica, sodium bicarbonate, sodium hypochlorite and water, is treated simply by a repetitive cycle of adding water, mixing, settling, decanting, and evaporating. After treatment, the slurries contain less than 5 ppm of dissolved arsenic and are considered non‐hazardous.
Potential problems using the TCLP to determine BDAT compliance
Authors: Reynolds Caroline C.
Published: February 2007

A major result of the Land Disposal Restrictions (LDR) is that all listed hazardous wastes must be treated prior to land disposal. When evaluating treatment options, generators will want to know whether the treated waste meets the Best Demonstrated Achievable Technology (BDAT) criteria for land disposal. To avoid enforcement action and penalties, analytical data must confirm that the treated waste meets BDAT criteria.

Many BDAT criteria are based on the constituent concentration in the Toxicity Characteristic Leaching Procedure (TCLP) extract of the waste. Since the TCLP uses an acidic solution to leach the waste constituents, reported results may be influenced by hydrolysis, interfering compounds or laboratory contamination. Sufficient quality assurance samples must be analyzed for the data to be court defensible.

This paper proposes methods for minimizing analytical problems and obtaining representative data. A case history illustrates several of the problems and related solutions.
Continuous flow thermal desorption of VOC's from activated carbon
Authors: Klobucar Joseph M. , Pilat Michael J.
Published: February 2007

A countercurrent thermal VOC desorber apparatus with 0.43 to 0.67 lb/hr (0.195 to 0.304 kg/hr) activated carbon flow and 0.43 to 0.49 scfm (0.88 to 1.00 kg/hr) purge air flow provided 26.6 to 77.7% VOC desorption efficiency over the 62 to 199°F (16 to 92°C) operating range. The VOC concentration of the carbon was measured at the carbon inlet, outlet, and two intermediate points in the desorber by thermogravimetric analysis. Inlet adsorbent carbon VOC concentrations ranged from 0.23 to 0.44 grams VOC/gram carbon. The VOC concentration of the purge air was measured at the purge air outlet and two points within the desorber by GC‐FID. The VOC concentration of the outlet purge air ranged from 14,627 to 44,209 ppm (0.023 to 0.070 grams VOC/gram air). The VOC concentrations measured in the activated carbon and in the purge air provided the oprating line data for plotting on an X‐Y diagram and together with the equilibrium isotherms resulted in mass transfer coefficients Kga in the 472 to 864 lb/ft3 hr (7,561 to 13,840 kg/m3 hr) range.
On‐site evaluation of treatment system requirements to satisfy direct and indirect discharge limits for a complex industrial wastewater: A case study
Authors: Cooper Abigail M. , Torrens Kevin D. , Musterman Jack L.
Published: February 2007

The promulgation of increasingly stringent effluent guidelines and penalities for permit violations has dictated the need for reliable and cost‐effective industrial wastewater treatment systems. This paper presents a case study that compares industrial wastewater treatment system requirements for indirect and direct discharge options. The results are based on a five‐month bench‐scale study that compared biological treatment and activated carbon treatment for removal of priority pollutants from a complex organic chemicals wastewater. Alternative discharge limits were defined by the OCPSF categorical limits, local POTW requirements and state water quality standards.

The results of this study indicated that suspended solids removal followed by granular activated carbon (GAC) columns was the most cost‐effective pretreatment system.
Water purification and recycling using the CDI process
Authors: Ganzi Gary C. , Wood Jonathan H. , Griffin Christopher S.
Published: February 2007

Continuous Deionization (CDI)—also known as electrodeionization—is a hybrid separation process combining ion‐exchange resins and ion‐exchange membranes. A voltage gradient is used as the driving force for separations. The process is capable of acieving high levels of purification and concentration of dissolved ionic solutes without the use of chemical regenerants. Early research in the field focussed on the removal and concentration of trace metals from effluent streams. In CDI equipment, the electrical conductivity of only the diluting compartments is enhanced by the ion‐exchange packing. For this reason, purification levels often improve as the water recovery increases. Examples of improved performance are provided as measured by water conductivity, and levels of dissolved carbon dioxide.

In high purity water production, concentration ratios of 1,000 to over 10,000 are achieved at high electrical efficiency. The process is therefore well‐suited for liquid purification applications requiring a high extent of deionization coupled with a high concentration, low volume concentrate stream with no net chemical additives. Using a municipal water source, purification levels, as measured by electrical conductivity, of 10 to 0.1 microsiemens/cm are achievable at 75–80% water recovery. Recovery is limited primarily by the precipitation of solids in the concentrating stream. In specialized applications, e.g., for production of less than 0.1 microsiemens/cm ultra‐pure water downstream of reverse osmosis (RO), CDI product water recoveries of 95% are achievable. Typical flow diagrams are provided and described.
Integrated anaerobic‐aerobic process for the biodegradation of chlorinated aromatic compounds
Authors: Armenante Piero M. , Kafkewitz David , Lewandowski Gordon , Kung Cheng‐Ming
Published: February 2007

An integrated anaerobic‐aerobic process for the complete mineralization of 2,4,6‐trichlorophenol (used in this work as the model toxic halogenated aromatic compound to degrade) was successfully tested and operated. The sludge obtained from the anaerobic digester of a commercial treatment plant was used to obtain an anaerobic consortium capable of partially dechlorinating 2,4,6‐trichlorophenol (2,4,6‐TCP). The clarified and sterilized effluent from the same anaerobic digester was used as the medium for the anaerobic consortium. During the anaerobic process 2,4,6‐TCP was first dechlorinated to 2,4‐dichlorophenol and then to 4‐chlorophenol (4‐CP). Stoichiometric amounts of 4‐CP were recovered. Similar results were obtained when the anaerobic microorganisms were immobilized on Manville R‐635 silica beads. After immobilization, the consortium was able to dechlorinate 150 μM of 2,4,6‐TCP in four days. Pseudomonas Glathei and an indigenous culture obtained from same sludge used to produce the anaerobic enrichment culture were shown to be able to degrade the 4‐CP produced from the anaerobic dechlorination of 2,4,6‐TCP. However, for the aerobic 4‐CP mineralization to occur the medium had to be buffered with phosphate, since high pH would inhibit the aerobic bacterial activity. It is expected that the proposed approach will be used to treat recalcitrant halogenated compounds that are not amenable to conventional biological treatment.
Sorbent/urea slurry injection for simultaneous SO2/NOx removal
Authors: Gullett Brian K. , Bruce Kevin R. , Hansen Walter F. , Hofmann John E.
Published: February 2007

The combination of sorbent injection and selective noncatalytic reduction (SNCR) technologies has been investigated for simultaneous SO2/NOx removal. A slurry composed of a urea‐based solution and various Ca‐based sorbents was injected at a range of temperatures and reactant/pollutant stoichiometries. Testing on a natural gas pilot‐scale reactor with doped pollutants achieved up to 80% reduction of SO2 and NOx at reactant/pollutant stoichiometric ratios of 2 and 1, respectively. SO2 emission reductions from slurry injection were enhanced compared with dry Ca(OH)2 sorbent injection methods possibly due to sorbent fracturing to smaller, more reactive particles. Emissions from NH3 slip and N2O formation were reduced in comparison with others' published results while similar NOx reductions were obtained. The injection of the urea‐based solution enhanced the SO2 removal, likely due to the formation of a (NH4)2Ca(SO4)2•H2O compound. The results of this pilot scale study have shown high reduction of both SO2 and NOx, suggesting the need for full scale studies to further assess this combined sorbent/urea‐based slurry injection technology.
Evolution of the superfund remedy selection process, including an assessment of implementation of permanent and alternative remedial technologies
Authors: Dienemann Erik , Goldfarb William , Ahlert Robert C.
Published: February 2007

The history of the Superfund program has been controversial, especially with respect to the development of the remedy selection process. During the early 1980's, USEPA rarely selected permanent remedies or alternative treatment technologies, relying on disposal and/or containment remedies. Dissatisifaction with the pace and extent of cleanup of the Nation's hazarous waste sites resulted in public and political pressure to address this situation. In response, USEPA's selection of alternative remedial technologies accelerated somewhat during the mid 1980's. At the same time, the original Superfund law and key regulations were being overhauled, culuminating in enactment of the Superfund Amendments and Reauthorization Act (SARA) in late 1986. SARA emphasized selection of permanent remedies and alternative remedial technologies that treat a site's contaminated source materials. SARA also established the Superfund Innovative Technology Evaluation (SITE) program to evaluate alternative remedial technologies. Since SARA, USEPA claims continued acceleration in the selection of permanent remedies and alternative technologies, while critics question the permanence of many of EPA's selected remedies.
Critical evaluation of PCB remediation technologies
Authors: Amend Laura J. , Lederman Peter B.
Published: February 2007

Polychlorinated biphenyls (PCBs) are a family of aromatic compounds consisting of a biphenyl molecule which has been chlorinated to form a large number of possible congeners. The number of chlorine atoms they can contain (from 1 to 10) varies, as does the placement of the chlorine atoms on the biphenyl molecule. Thus, a polychlorinated biphenyl is one of 209 compounds having the formula: C12H10–nCln. Due to their excellent heat stability, fire retardance and electrical insulating properties, they gained widespread use as dielectric fluid incorporated in electrical transformers and capacitors. They were also incorporated in products as various as plastics, hydraulic fluids, surface coatings, inks, paints, pesticides, lubricants, and carbonless copy paper.
Evaluation of a hydraulically‐installed suction lysimeter to obtain representative soil water samples
Authors: Chaimberg Mark , Carty Ronald H. , Scroppo Joseph A.
Published: February 2007

The existing technology for obtaining liquid from the vadose zone involves drilling a bore hole, introducing a silica slurry packing, inserting a sampling device, and backfilling the hole. The high cost of drilling and backfilling contribute to the considerable expense of this procedure. Moreover, drilling through potentially contaminated soil increases the possibility of expanding the area of contamination. In this study, a novel small diameter suction lysimeter with a porous ceramic section was designed and tested. The stainless steel ram‐tipped lysimeter was designed to be installed into the ground using a hydraulic ram without the need of drilling a bore hole, thereby reducing the expense and potential for cross‐contamination. Simulated field testing was employed to evaluate the performance of the hydraulically‐installed lysimeter as compared to a lysimeter installed using the standard silica slurry packing technique. The decrease in sample volume uptake due to plugging in the pores of the ceramic section was investigated for the lysimeters installed both hydraulically and with the silica slurry packing, in three types of soil: medium sand, silty clay, and a clayey topsoil‐medium sand blend. The soil moisture operating range for the lysimeters was ascertained in a test chamber filled with a blend of clayey topsoil and medium sand. An investigation of the effect of sampling on the concentration of solutes was performed with aqueous solutions of ethanol and phenol.
Soil decontamination via microwave and radio frequency co‐volatilization
Authors: George Clifford E. , Lightsey George R. , Jun Inchul , Fan Jiayi
Published: February 2007

Microwave and radio frequency heating techniques have proven to be suitable on the laboratory scale and for small scale field studies as energy sources for thermal processing of solvent contaminated hazardous waste and contaminated soils. The process described here is a technique that could be used to remove contaminates from soils or sludges on‐site, collect the contaminate in an activated carbon absorption tower, and move the activated carbon off site for regeneration. The data presented show that destruction and removal efficiencies (DRE) of near 100% can be achieved for phenanthrene in simulated API separator sludge and 60% for pentachlorophenol in contaminated soil. A technique to enhance microwave absorption by the addition of carbon particles to the soil or sludge sample to be treated is discussed.
Supercritical extraction of polynuclear aromatic hydrocarbons from soil
Authors: Kothandaraman S. , Ahlert R. C. , Venkataramani E. S. , Andrews A. T.
Published: February 2007

Adsorption and desorption of polynuclear aromatic hydrocarbons from soil in the presence of Supercritical CO2 is studied. The soil adsorption isotherms are described by the Freundlich and BET models. Polar modifiers like methanol and water are found to exhibit a strong desorptive influence. A simple, single‐parameter model using linear desorption kinetics is used to fit the desorption data.
Adsorption/desorption characteristics of lead on various types of soil
Authors: Peters Robert W. , Shem Linda
Published: February 2007

Laboratory studies were conducted to address the phenomena of adsorption/desorption of lead onto various types of soils, both in the absence and presence of the chelating agent, ethylenediaminetetraacetic acid (EDTA). The linear and Freundlich isotherm models provided adequate description of the adsorption/desorption behavior. Over the range of EDTA concentrations employed in the study (0.1 to 0.10M), no significant difference in the isotherm parameters was observed as a result of the applied EDTA concentration. The presence of EDTA significantly altered the adsorption/desorption behavior of lead on the soil, resulting in less of the metal being adsorbed. The soil with the higher silt/clay content had a greater amount of lead adsorbed onto it (as compared with the sandy soil).
Electrokinetic removal of selected heavy metals from soil
Authors: Pamukcu Sibel , Wittle J. Kenneth
Published: February 2007

The electrokinetic process is an emerging technology for in situ soil decontamination, in which chemical species, both ionic and nonionic are transported to an electrode site in soil. These products are subsequently removed from the ground via collection systems engineered for each specific application. Electrokinetics refer to movement of water, ions and charged particles relative to one another under the action of an applied direct current electric field. In a porous compact matrix of surface charged particles such as soil, the ion containing pore fluid may be made to flow to collection sites under the applied field.

The work presented here describes part of the effort undertaken to investigate electrokinetically enhanced transport of soil contaminants in synthetic systems. The results of the laboratory study presented here indicate that electrokinetic enhancement of contaminant transport in soils is a viable technology; development of this technology for wide range of applications hinges upon better understanding of the transient chemical and physical processes during application of current through soil/contaminant systems.
Nitrous oxide sampling, analysis, and emission measurements from various combustion systems
Authors: Hulgaard Tore , Dam‐Johansen Kim
Published: February 2007

Nitrous oxide (N2O) emissions from various combustion systems was measured by use of two analytical methods, the performance of which was evaluated together with the sampling procedures. One analytical method is grab sampling followed by analysis by gaschromatography (GC). This procedure was found to give accurate results, provided SO2 and H2O were removed during sampling in order to avoid N2O formation in the sample. An evaluation of a continuous infrared N2O analyzer shows that it is a useful instrument if measures are taken to eliminate or adjust for interferences from CH4, SO2, H2O, and to a minor extent also from NH3. A considerable formation of N2O was found when a gas containing SO2 and NO was scrubbed in a weak acid solution.

The sampling program from a variety of combustion systems revelas that N2O emissions usually are low (0–5 ppm) from the combustion of pulverized coal. The results from a gas turbine, a laboratory gas‐fired fiber burner, and a domestic oil combustor are also in the very low range, whereas emissions from combustion of straw or wood were slightly higher. Even higher emissions were observed from circulating fluidized bed combustion (CFBC), from which the level of emissions increased with decreasing combustion temperature and increasing excess air levels. Sampling inside the CFBC reactor showed that N2O formation is particularly rapid at the transition from reducing to oxidizing conditions at the secondary air inlet. Pilot plant experiments with the selective non‐catalytic reduction of NO by urea or ammonia resulted in a large increase in N2O emissions during the injection of urea, whereas almost no increase was found during the injection of ammonia.