bluuebunny/crossref_metadata_2025 huggingface dataset:
Sensitivity of extreme events to climate change: The case of autocorrelated time series
Authors: Katz Richard W. , Brown Barbara G.
Published: February 2007

The relative sensitivity of an extreme event is defined as the partial derivative of its probability with respect to the location or scale parameter of the distribution of the variable involved. Of particular interest in climate applications are extreme events of the form, the maximum of a sequence of observations of the variable exceeding a threshold. In this case, the relative sensitivities are directly related to the hazard rate for the distribution of the maximum. By means of simulations, this hazard rate is determined for the maximum of a finite sequence of autocorrelated random variables. For large values, the hazard rate rises more steeply than the asymptotic theory based on the type I extreme value distribution would predict. Unless the degree of autocorrelation is quite high, the hazard rate does not differ much for large values from that for independent time series. The hazard rate for the so‐called “penultimate approximation”, based on the type III extreme value distribution, is also compared to the exact hazard rate under dependence. These results imply that the relative sensitivity of extreme events to overall climate change is even greater than the asymptotic theory would predict. Time series of daily maximum temperature, data that possess substantial autocorrelation, are utilized for illustrative purposes.
Spatial large‐scale correlations for optimal interpolation of temperature, salinity and nutrient concentrations in the Gulf of Finland
Authors: Toompuu Aleksander , Wulff Fredrik
Published: February 2007

Spatial correlations of temperature, salinity and nutrient concentrations in the Gulf of Finland are estimated for winter, spring, summer and fall. The correlation estimates are based on the results of observations in the Gulf of Finland for the period 1972–1991. The time and space resolution of the correlation model are determined by averaging the original data in time over each month and in space over the cells with horizontal dimensions equal to 10′ in the east–west and 20′ in the south–north direction and to the standard sampling depth intervals in the vertical direction. The fluctuations of the averaged data are defined as deviations of the month and cell average data values from the seasonal 20‐year overall mean values. The model of spatial correlation is based on the assumption that the fluctuations of the month‐and‐cell average data form a random sample out of a spatially homogeneous, horizontally isotropic and temporally stationary field. Most of the estimated correlations are positive, except for the vertical correlation component of salinity in summer, which shows considerable negative values at the distance lags exceeding 30 m. As an example of assimilation of the estimated correlations, the statistical (optimal) linear interpolation approach was applied for estimation of the optimal location of a measurement site, additional to the three currently used international monitoring stations, commonly known as LL12, LL7 and LL3A, in the Gulf of Finland. The optimal location of the additional fourth measurement site, which leads to the least average interpolation error, was found to be within the vertical column of cells with co‐ordinates 60° 00′ N 28° 10′ E for salinity and 60° 00′ N 28° 20′ E for total phosphorus concentration measurements. The same average error cannot be achieved by increasing the sampling frequency at the three present international monitoring stations.
The detection of change in spatial processes
Authors: Martin E. B. , Scott E. M.
Published: February 2007

The question of whether the spatial distribution of a characteristic of interest has changed over time is of interest within the environmental sciences, since spatial evolution may be informative about the underlying environmental processes affecting the characteristic. Techniques currently available for investigating change in spatially defined processes are in the main either subjective in nature or else ignore the spatial component. A hypothesis testing procedure based on a contour representation of the spatial distribution of the characteristic of interest has been developed and will be described in this paper. The approach does not require that observations be recorded at the same location, and thus is generally applicable. The degree of change between the contoured surfaces has been quantified in terms of various statistics which describe the rotational, translational and scalar aspects of change. The propoerties of the various statistics have been investigated through an extensive simulation study, which examined a range of factors, including the surface fitting procedure (Kernel density estimation) the number and choice of contour levels and the effect of random noise present within the system due to the measurement process. Finally the method is illustrated on the historical climate record of the U.S.A. The temperature field of the contiguous U.S.A. is studied for change over a 50 year period.
Health and environment: Public health decisions based on evidence, psychology and politics
Authors: Bonham G. H.
Published: February 2007

The concern is with the magnitude of Alzheimer's disease as a social and health problem and with the appropriateness of public action when there is a lack of firm international consensus on the role of aluminium either as a causative agent or as a factor contributing to the prevalence of Alzheimer's disease. From an examination of current and historical events, there is an analysis of the reasons why some technologies and health measures translate easily towards appropriate public action or public policy whereas others trigger little or no response. The concept of congruence of interest is utilized. When there is a lack of international consensus the appropriateness of prudent avoidance and of collateral justification is discussed. Further priorities for research are suggested.
Mean‐square values of concentration in a contaminant cloud
Authors: Labropulu F. , Sullivan P. J.
Published: February 2007

A simple and relatively general analytic expression for the distributed second central moments of scalar concentration is derived. The ‘fluctuations’ or mean‐square values are given in terms of the mean concentration field and apply in either an inertial or cloud centre‐of‐mass reference frame. Clouds in homogeneous grid turbulence, in the neutral atmospheric boundary layer, and in the inertial sub‐range are used as illustrative examples.
Evaluating the performance of a water system: An application to the aragón and gállego rivers in Spain
Authors: Calvete Herminia , Mallor Fermín , Miguel Miguel San
Published: February 2007

This paper describes the use of both an optimization technique and a simulation technique for assessing the performance of alternative configurations for a water system. This methodology is applied to the Aragón ‐ Gállego system, in Spain. This reservoir system is used primarily to supply water for irrigation. The goal is to get more water in conditions to be used for the irrigation of several new areas in the basins. Given a specific configuration in the optimization step, the out‐of‐kilter algorithm is applied to a specially designed network that models the system in order to know the best way to distribute the water resources in a year. Demands in each period are fixed and cost coefficients of the variables are assigned to reproduce the different priorities of the demands. The simulation technique permits one to compare the different configurations and to assess their performance over time.
Separation coefficient for analysis of large environmental data sets: Ion concentrations of lake superior and lake huron
Authors: Jensen A. L.
Published: February 2007

When statistical hypotheses are tested with large environmental data sets, such as those available for ionic constituents of the Great Lakes, even small differences between means are detectable, and the usual result is that all or nearly all differences tested are statistically significant. In this situation, hypothesis testing is not useful. Differences between means also are not useful for comparisons because of differences in units of measurement and variances. The t‐statistic is used to determine if two populations are significantly different, but the value of t is not useful for evaluating the degree of separation of two populations because the value of t is influenced by sample size, t has no lower or upper bound, and the value of t has no meaningful interpretation. A separation coefficient is developed that measures the proportion overlap of two normally distributed populations; it is not influenced by sample size, is easily calculated, and takes values between 0 and 1. The separation coefficient was applied to examine differences in ion concentrations between Lake Superior and Lake Huron. The sample sizes were large and all differences were statistically significant, but the coefficients of separation varied from 0.07 to 1, which indicates that concentrations of some ions in the lakes were more similar than others. The pattern in the coefficients of separation indicate meaningful differences between the lakes.
Shrinkage estimation in pooling data for arbitrary populations
Authors: Ahmed S. E. , Khan S. M.
Published: February 2007

The classical problem of pooling data of two independent random samples drawn possibly from two identical arbitrary populations is considered. Decision to pool the two samples or not is based on the outcome of the preliminary test and then a shrinkage technique is used. In an asymptotic setup, the distributional risks of the proposed estimators are derived and compared. This study reveals the robustness property of the proposed shrinkage preliminary test maximum likelihood estimator (SPTMLE) when the assumed restraints may not hold. It is shown that the proposed estimator provides a wider range than the usual preliminary test maximum likelihood estimator (PTMLE) in which it dominates the classical estimator. More importantly, the SPTMLE provides more meaningful size for the preliminary test.
Relative precision of stratified sampling, sampling with probability of selection proportional to size, and simple random sampling with ratio estimation
Authors: Jensen A. L.
Published: February 2007

Variably of estimates in natural resources and the environmental sciences is high, and methods for increasing precision are important. Three different approaches have been applied to increase precision of sample based estimates by including auxiliary variables: these are stratified sampling, sampling with probability of selection proportion to size, and ratio estimation. The objective of this study was to determine the conditions under which each of these methods had a small error of estimate. Bivariate normal populations were generated with different coefficients of variation for both the variable of interest and the auxiliary variable, and with different correlations between the auxilliary variable, and with different correlations between the auxiliary variable and the variable of interest. All three approaches for increasing precision were applied to estimate the population means and determine the precision of the estimates relative to that of simple random sampling. Stratified sampling was the most precise method unless the coefficients of variation of both the variable of interest and the auxiliary variable were small and the correlation was high. This condition does not occur often in natural resources or the environmental sciences, and stratified sampling most often would be the best method for increasing precision.
Emergency planning considerations for chemical plants
Authors: Michael Eugene J. , Bell Donald W. , Wilson John W. , McBride Gregg W.
Published: February 2007

Well‐developed contingency plans for potential emergencies at chemical plants provide safeguards for the plants and their surrounding communities. The size of the emergency planning zone (EPZ) is first determined by use of mathematical models which estimate the health effects and other consequences of toxic, flammable, and explosive chemical releases to the environment. Emergency response plans and procedures are then developed for the EPZ. Finally, a training program is developed and used to ensure that all emergency response personnel are aware of the actions which they must take in the event of an actual emergency.
Stringfellow leachate treatment with RBC
Authors: Opatken E. J. , Howard H. K. , Bond J. J.
Published: February 2007

A study was conducted with a rotating biological contactor (RBC) for treatment of leachate from the Stringfellow hazardous waste site in Riverside County, California. The leachate was transported from California to Cincinnati, where a pilot sized RBC was installed at the U.S. EPA's Testing and Evaluation (T&E) Facility.

A series of kinetic runs were made with primary effluent from the City of Cincinnati's Mill Creek Sewage Treatment Plant to develop a biomass on the disks and to obtain a standard kinetic removal rate. These runs were then followed with Stringfellow leachate experiments that included.

Operations at various ratios of leachate to primary effluent.

Operations at 100% leachate.

Operations to increase the percentage removal of dissolved organics.

This paper reports on the results from these experiments and the effectiveness of an RBC to adequately treat leachate from the Stringfellow hazardous waste site.
Pilot process variable study of coolside desulfurization
Authors: Yoon H. , Stouffer M. R. , Rosenhoover W. A. , Withum J. A. , Burke F. P.
Published: February 2007

The Coolside desulfurization process is a dry sorbent injection technology developed for retrofit SO2 control in coal‐fired utility power stations. The process is low in capital and space requirements since, in its ideal configuration, the existing ductwork and particulate collector are used as the SO2‐sorbent reaction spaces. It has been developed through laboratory and 1 MW‐scale field tests using hydrated lime as the primary process sorbent by Consolidation Coal Company (Consol). The field work showed promising results with observed SO2 removal ranging up to 80%. In order to optimize the process performance through improved understanding of the process fundamentals, Consol constructed and is operating a 0.15 MW pilot test unit. This paper describes the results of a process variable test program, a first series of tests made in the pilot unit, and the unit operability observed during the test work.
Removal of pollutants from dilute wastewater by the PACTTM treatment process
Authors: Dietrich M. J. , Copa W. M. , Chowdhury A. K. , Randall T. L.
Published: February 2007

The PACTTM wastewater treatment system, which incorporates the use of powdered activated carbon in a conventional activated sludge system, has been in use for the treatment of wastewaters from both municipal and industrial sources. The combination of physical adsorption with biological oxidation and assimilation in the PACT system has been shown to be particularly effective in treating dilute wastewaters which are variable in concentration and composition, highly colored, or contain materials which are refractive or potentially toxic to biological growth.

Dilute wastewaters treated successfully in bench‐scale PACT systems include those from organic chemicals, pharmaceuticals, metal coating, shale oil retort water, evaporation ponds, leachates, and rainwater runoff. The COD of these wastewaters ranged from a low of 643 mg/l to 23,700 mg/l. Specific pollutants present included compounds such as phenols, cyanides, thiocyanate, pesticides, and priority pollutants. The PACT wastewater treatment process has successfully treated these wastewaters and produced effluents meeting POTW or direct environmental discharge requirements. Operational parameters and performance results obtained for a number of bench‐scale PACT systems are presented.
Design of a tracking system for hazardous waste minimization
Authors: Wentz Charles A. , Chiu Shen‐Yann , Habegger Loren J. , Martino Louis E. , Peters Robert W.
Published: February 2007

The purpose of this study is to develop a waste tracking system as a prerequisite to a waste management model for subsequent waste minimization.
Elevated, concrete buildings for long‐term management of hazardous wastes
Authors: Walters James V. , Moffett Tola B. , Sellers Jerry D. , Lovell W. Adrian
Published: February 2007

Large, permanent buildings that are constructed of prestressed concrete, can withstand hurricane‐force wind loadings, and have extremely long lives can be used for long‐term storage of hazardous wastes. The buildings protect against seepage of leachate into soils and ground waters, emissions of volatiles, and contact of wastes with precipitation. Materials stored within the buildings would be available when technology and economics make recycling feasible. Hazardous wastes would be stored almost 10 feet (3.05 m) above land surface in a building designed for sub‐floor, walk‐through inspections for leaks. The proposed buildings can be as large as 250 feet (76.2 m) on a side and 70 feet (21.3 m) high and can support 9,000 pounds (40,000 N) of waste loading per square foot (0.305 m) of floor area. Each building, which can be constructed at virtually any location, would hold enough hazardous wastes to provide millions of dollars of return from construction of each building.
Residential combustion appliances: Venting and indoor air quality
Authors: Hayden A. C. S.
Published: February 2007

Increased interest in energy conservation, changes in airtightness, appliance design and building materials, along with fuel switching, have all combined to potentially raise the level of pollutants in the indoor environment, resulting in increased concern for indoor air quality.
In‐situ extraction of industrial sludges
Authors: Legiec I. A. , Kosson D. S.
Published: February 2007

In‐situ extraction for the removal of organic contaminants from impounded industrial sludges has been carried out at pilot‐scale at a Superfund site. Laboratory studies were carried out on split‐spoon core samples obtained at the end of the operational year and on untreated sludges. Pilot plant results and sludge characteristics before and after treatment are presented, focusing on the effectiveness of the forced extraction process.
Anaerobic treatment of pulp and paper mill wastewaters
Authors: Lee John W. , Peterson David L. , Stickney A. Ray
Published: February 2007

Secondary treatment of pulp and paper mill wastewaters for biochemical oxygen demand (BOD) removal worldwide has traditionally been accomplished, and particularly in North America, by aerobic treatment processes, including aerated stabilization basin and activated sludge. In recent years, however, interest in applying anaerobic processes to treat pulp and paper mill effluents has increased, with at least 25 full‐scale installations currently operating or under construction.
Effective reduction of emissions from resource recovery operations
Authors: Teller Aaron J.
Published: February 2007

The emission control system for the Commerce California Resource Recovery Facility is a Teller semi‐dry unit using lime as neutralizing agent and a phonolite (Tesisorb) dry venturi injection material. The system, installed in 1987, has exhibited a 98% on‐line reliability. The system emissions for particulate and acid gases were approximately one‐third of the California regulations. The uniqueness in performance was the reduction of the respirable particulates to less than 0.5 mg/Nm3 and the reduction of dioxins, toxic equivalent to less than 0.009 ng/Nm3.
Innovative thermal destruction technologies
Authors: Lee C. C. , Huffman George L.
Published: February 2007

Five innovative technologies for thermally destroying hazardous wastes were selected and are described. They are oxygen‐enriched incineration, Westinghouse/O'Connor combustor, circulating bed combustion, infrared system, and plasma arc. Two important criteria used in selecting these technologies are that they are at least at the stage of pilot‐scale demonstration and appear to be promising in terms of destruction effectiveness.
Use of carbon adsorption processes in groundwater treatment
Authors: Stenzel Mark H. , Merz William J.
Published: February 2007

One of the leading treatment technologies for reduction of organic contaminants in groundwater has become the adsorption process utilizing granular activated carbon (GAC).

This paper presents a methodology for selecting the proper adsorption system design. The use of the isotherm test for evaluation of carbon adsorption is discussed, with new data on adsorption of VOCs presented. The use of the dynamic column study for system design and its relationship to the isotherm test is reviewed using actual case studies. Design and economics for full‐scale GAC systems are discussed. The use of adsorption to remove organic contaminants from vapor sources resulting from groundwater treatment is also reviewed.
Reduction of volatile organic compounds in aqueous solutions through air stripping and gas‐phase carbon adsorption
Authors: Fang C. S. , Khor Sok‐Leng
Published: February 2007

Aqueous solution of volatile organic compounds (VOC's) is a waste stream of many chemical process industries. Conventionally, it is treated with a costly liquid‐phase activated carbon adsorption process. An alternative process is studied, which is the combination of air stripping and gas‐phase activated carbon adsorption. The removal of VOC's from waste‐water can be as high as 99.8%, using a packed column for air stripping at room temperature. These VOC's include vinyl chloride, carbon tetrachloride, trichlorethylene, 1,1‐dichloroethane, toluene, chloroform, 1,1,1‐trichloroethane, benzene and xylene. These VOC's are separated from air and recovered through a carbon adsorption‐regeneration cycle. The cost of VOC removal and recovery is in the range from $0.457 to $0.899 per 1000 liters.
Research investigations at the municipal and clinical waste incinerators in Sheffield, UK
Authors: Swithenbank J. , Nasserzadeh V. , Ewan B. C. R. , Delay I. , Lawrence D. , Jones B.
Published: February 2007

After recycle of spent materials has been optimized, a proportion of waste must be dealt with in the most environmentally friendly manner available. For materials such as municipal waste, clinical waste, toxic waste and special wastes such as low radioactive wastes, incineration is often the most appropriate technology. The study of incineration must take a process system approach covering the following aspects:

Collection and blending of waste

The two stage combustion process

Quenching, scrubbing and polishing of the flue gases

Dispersion of the flue gases and disposal of any solid or liquid effluent

The design of furnaces for burning a bed of material is being hampered by lack of an accurate mathematical model of the process, and some semi‐empirical correlations have to be used at present. The prediction of the incinerator gas phase flow is in a more advanced stage of development using computational fluid dynamics (CFD) analysis, although further validation data is still required. Unfortunately, it is not possible to scale down many aspects of waste incineration, and tests on full scale incinerators are essential. Thanks to a close relationship between SUWIC and Sheffield Heat & Power Ltd., an extended research program has been carried out at the Bernard Road Incinerator plant in Sheffield. This plant consists of two Municipal (35 MW) and two Clinical (5 MW) Waste Incinerators which provide district heating for a large part of city. The heat is distributed as hot water to commercial, domestic (>5000 dwellings) and industrial buildings through 30 km of 14′ pipes plus a smaller pipe distribution system. To improve the economics, a 6 MW generator is now being added to the system.

During the last decade, many investigations have been carried out [1–6] and a SUWIC laboratory is located at the plant.
New techniques for solvent recovery and elimination of wastewater emissions during vacuum process operations
Authors: Perlmutter Barry A.
Published: February 2007

The pharmaceutical and chemical process industries are concerned with controlling volatile organic compound (VOC) emissions for several reasons: to meet environmental regulations, for increased worker safety, and to minimize product losses. Various methods can be used including flaring and carbon adsorption. These techniques are end‐of‐the‐pipe solutions and are not integral with the process operation itself.

An improved technique for the recovery of solvents during reaction, distillation, evaporation, drying, filtration, mixing, and other vacuum operations is the APO‐VAC vacuum/gas compressor system. The skid‐mounted, engineered package is based upon a single stage liquid ring vacuum pump. The system allows for the recovery and reuse of clean solvent with minimum air emissions and zero liquid emissions. VOC and biological oxygen demand (BOD) regulations are met by this technology.

The paper reviews the technical details of the system and presents test results and on‐site operational data. Specific case histories involving methylene chloride recovery and acid/toxic gas neutralizations are also included.

In the chemical processing industry (CPI) the generation of vacuum is a necessity. Many chemical processes take place more easily, more quickly and more efficiently under vacuum than under atmospheric pressure, thus allowing better product quality at lower production cost. If it is a “wet” process involving the use of solvents then solvent recovery becomes an important consideration because of cost savings associated with its recovery as well as environmental benefits.

These objectives have stimulated the development of the APOVAC system concept which is based on the principle of closed loops or circuits. Since its development, the APOVAC system has enhanced today's chemical process technology through solvent recovery and recycling, elimination of wastewater effluent, and reduction of gas emissions thus contributing to a technically efficient and environmentally acceptable operation.
Important design considerations in wastewater treatment plants
Authors: Vacker Don
Published: February 2007

Many wastewater treatment plants, over the years, have been designed and constructed with little thought being given to details that allow the whole to work as a system, and often provides little ease of operation and maintenance. Based on over 35 years experience in the field, the following are some observations of often overlooked details which a design engineer should consider. This will be categorized into the following: Front End Design, Treatability Studies, Primary Treatment, Biological Treatment, Secondary Clarification, VOC Control, Solids Dewatering and Disposal, Recycle/Reuse, and Spent Caustic Treatment.
Modeling of acetone biofiltration process
Authors: Hwang Shyh‐Jye , Tang Hsiu‐Mu , Wang Wen‐Chuan
Published: February 2007

Biofiltration has been validated as a promising alternative to other conventional air pollution control technologies [1–3]. The objective of this research was to investigate the kinetic behavior of the biofiltration process for the removal of acetone, which was used as a model compound for highly water‐soluble gas pollutants. Experiments were conducted in a laboratory‐scale biofilter with a mixture of sieved compost and inert porous particles as the filter material. It was found that the elimination capacity of this biofilter could reach up to a high value of 80 g/(m3hr).

A mathematical model was developed by taking into account diffusion and biodegradation of acetone and diffusion of oxygen in the biofilm, mass transfer resistance in the gas film, and flow pattern of the bulk gas phase. The simulated results obtained from the proposed model indicated that mass transfer resistance in the gas phase was negligible for this biofiltration process. Analysis of the relative importance of individual rate steps indicated that the overall acetone removal process was primarily limited by the oxygen diffusion rate. Moreover, the gas phase acetone concentration profile along the biofilter and the elimination capacity predicted by the proposed model agreed well with the experimental results.
Cesium‐removal flow studies using ion exchange
Authors: Lee D. D. , Walker J. F. , Taylor P. A. , Hendrickson D. W.
Published: February 2007

The development, selection, and implementation of technologies to be used in removing cesium from radioactive liquid wastes in preparation for their final disposition is discussed.

The methodology involved testing several proposed sorbents in ion‐exchange columns using actual liquid wastes from underground storage tanks at U.S. Department of Energy sites. The sorbents initially tested included resorcinolformaldehyde resin (RF), CS‐100 resin, SuperLig 644C resin, 3M WEB with embedded SuperLig 644, granular potassium cobalt hexacyanoferrate, and granular crystalline silicotitanates (CSTs).

The results of the bench‐scale testing were used to select the sorbent for the full‐scale Cesium Removal Demonstration Project (CsRD). This project will treat up to 25,000 gal of radioactive supernatant stored in the Melton Valley Storage Tanks (MVSTs) at Oak Ridge National Laboratory (ORNL). The demonstration system is modular in design and will process supernatant at flows up to 5 gal/min through 12‐in.‐diam columns. Following the demonstration the system will be used for routine processing of tank waste at ORNL.

To show their applicability to wastes at other sites, RF and CST sorbents were tested in a bench‐scale column using a diluted Hanford supernatant liquor (double‐shell slurry feed) from tank 241‐AW‐101. The results are compared with those from tests of MVST supernatant.
Measuring volatile chemical emission rates from large waste disposal facilities
Authors: Hwang Seong T. , Thibodeaux L. J.
Published: February 2007

A novel method for measuring emission rates from large surface impoundments.
Hazardous waste destruction processes
Authors: Freeman Harry M.
Published: February 2007

As increasing restrictions are placed on the landfill disposal of organic wastes, innovative thermal processes are expected to provide acceptable alternative approaches.
Separation of PCBs from hydraulic oil
Authors: Mink William H. , Smith R. K. , Carlton H. E. , Longanbach J. R.
Published: February 2007

A modular pilot plant has successfully reduced the PCB level from approximately 1000 ppm to 1 ppm in hydraulic oil.
New wastewater treatment for industrial applications
Authors: Bowker Robert P. G.
Published: February 2007

Pilot and full scale studies on a variety of high‐strength industrial wastes demonstrate the ability of anaerobic systems to treat these materials effectively with the added bonus of methane production.
Recovery process for complexed copper‐bearing rinse waters
Authors: Spearot R. M. , Peck J. V.
Published: February 2007

A state‐of‐the‐art review of the advantages and disadvantages of currently available technologies.
Mineral processing water treatment using magnesium oxide
Authors: Schiller Joseph E. , Tallman Daniel N. , Khalafalla Sanaa E.
Published: February 2007

Comparative tests show magnesium oxide to be superior to silica sand and garnet sand for the filtration of several different particulates and to lime for the precipitation of heavy metals.
Polishing treatment of coal liquefaction wastewaters
Authors: Brown C. H. , Harris M. T. , Roop R. D.
Published: February 2007

Detailed description of a mobile wastewater‐treatment pilot plant with application to actual coal‐liquefaction wastewaters.
Bench‐scale treatment of lurgi gasifier and H‐coal wastewaters by the PACT system
Authors: Randall Tipton L. , Canney Patrick J. , Berndt Craig L. , Rollins Richard M. , Soukup Charles L.
Published: February 2007

A revealing progress report on the continuing effort to develop a cost‐effective process for the production of synfuels by the coal‐gasification route.
Management of industrial hazardous wastes
Authors: Overcash Michael R. , Eagleton Lee C.
Published: February 2007

An organized hierarchy brings out techniques which will truly solve the problems of long‐term storage of hazardous wastes.
Polymer flotation and activated carbon adsorption treatment for in situ tar sand process water
Authors: McTernan W. F. , Blanton W. E. , Boardman G. D. , Nolan B. T. , Kocornik D. J.
Published: February 2007

Process waters collected during a Department of Energy's in situ tar sand extraction experiment near Vernal, Utah were treated by polymer assisted induced air flotation and activated carbon adsorption. The flotation process removed over 99 percent of the organic load as emulsified bitumen but did little to reduce residual toxicity in the effluents. Activated carbon adsorption was needed to remove the toxic materials from the waste stream.

GC/MS analysis, using a modification of the EPA Method 625, yielded an estimated 2000 compounds in the untreated process water. Internal and recovery standards present at 10 ppm were totally obscured in the chromatogram. Flotation effluents contained 39 identified organic compounds; none of which was listed on EPA's hazardous chemicals list. Internal and recovery standards were immediately visible in the chromatogram. The GC/MS analysis was unable to determine the chemical basis for the toxic properties present.
Development of a combined ultrafiltration and carbon adsorption system for industrial wastewater reuse and priority pollutant removal
Authors: Van Gils G. , Pirbazari M.
Published: February 2007

This article describes a work‐in‐progress. The development work described herein has culminated in the construction of a full‐scale treatment system which is currently in operation and is being optimized in both its practical operating as well as its treatment process aspects.
Retrofit SO2 and NOx control technologies for coal‐fired power plants
Authors: Miller Michael J.
Published: February 2007

The United States currently depends on coal for over half of its electric power generation. Current legislative and regulatory initiatives related to acid rain and other environmental concerns have focused on retrofit controls on existing plants and increasingly stringent requirements for new plants. This paper focuses on some of the technological approaches United States utilities are using and could be using in the future to generate electric power cleanly and reliably. Those technologies discussed include precombustion controls (physical coal cleaning and coal switching/blending), combustion controls (low NOx combustion, furnace sorbent injection, and fluidized bed combustion), and postcombustion controls (flue gas NOx control, wet and dry flue gas desulfurization, and post‐furnace dry sorbent injection) The commercial status, economics, and critical issues for retrofit and new commercial application of these technologies to utility systems are discussed.
Coal desulfurization in a fluidized bed reactor
Authors: Ravindram M. , Kalvinskas John J.
Published: February 2007

Fluidized bed reactor technology was investigated as a means of developing a new simple and low cost process for coal desulfurization. Preliminary experimental results obtained in a 2.54 cm batch fluidized bed reactor have shown that over 80% total sulfur reductions can be achieved by sequential chlorination and dechlorination/hydrodesulfurization of high sulfur pulverized coals. Proximate and ultimate analyses of desulfurized coals have revealed enhanced carbon and fixed carbon levels and substantially reduced volatile, oxygen and hydrogen contents. While there was a minor increase in the ash content and heating value, nitrogen and chlorine contents were essentially unchanged.

Compared to an earlier slurry phase process, the fluidized bed reactors process has specific advantages such as shorter reaction times, fewer processing steps and reduced reactant requirements. A fluidized bed reactor process may thus have a potential of being developed into a simple and economic means of converting high sulfur coals to environmentally acceptable fuels.
Flue gas scrubbing process for sulfur dioxide and particulate emissions preceding CO2 absorption
Authors: Brady Jack D.
Published: February 2007

This article describes a 2‐stage scrubbing process which utilizes sodium hydroxide or sodium carbonate as the neutralizing chemical for sulfur dioxide and sulfur trioxide emissions to remove contaminants from gas streams preceding CO2 absorption processes.

Amine absorption processes are adversely affected by sulfur dioxide in the gas stream, and it is desirable to reduce sulfur dioxide concentrations to less than 5 ppm (vol).

Conventional flue gas desulfurization processes do not achieve outlet concentrations at this level. With appropriate controls on pH, ionic strength, and liquid recirculation rates, the sodium alkalies can achieve these outlet concentrations. When concentrations of sulfur dioxide absorbed become sufficiently large to make the economics of a simple throw‐away process uneconomical, the waste solutions can be regenerated in the double‐alkali process by reacting them externally from the scrubbing system with calcium compounds. This process is also described. Particular emphasis is placed on process design for reliability. Materials of construction, process controls, and process chemistry are discussed.
The hazardous waste research center at louisiana state university
Authors: Segesta Rosalind , Thibodeaux Louis J.
Published: February 2007

Hazardous waste and the problems associated with its proper disposal are the concerns of the Hazardous Waste Research Center (HWRC), located on the Baton Rouge Campus of Louisiana State University.

The Center is a part of the U.S. Environmental Protection Agency's “Centers of Excellence” program to conduct long‐term fundamental research in 3 major areas: (1) incineration/combustion; (2) alternate methods of treatment/destruction; (3) chemicals/materials interaction and stabilization.

The projects are interdisciplinary in scope, with faculty members from civil, mechanical, and chemical engineering, chemistry, and the marine sciences participating.

Future research directions will change to keep pace with the problems and needs of industry, waste handlers, government, and the public. The Hazardous Waste Research Center, in dealing with current problems and anticipating future needs, will help reduce the risk and/or extent of negative impact on the environment, on human health, or on the economy of the nation due to improper management or disposal of hazardous wastes.
Removal of heavy metals in POTW
Authors: Aulenbach Donald B. , Meyer Michael A. , Beckwith Eileen , Joshi Shrikant , Vasudevan Chittibabu , Clesceri Nicholas L.
Published: February 2007

Studies were conducted at three activated sludge treatment plants during normal operation. The heavy metals on the priority pollutants list were measured in the influent to each plant, the primary sedimentation effluent where applicable, the discharge after activated sludge treatment and secondary sedimentation, and in one case after a final polishing filter. Both the soluble and the total portions were measured.

Beryllium, nickel, and thallium were not found in detectable levels in any of the plant influents. Mercury was found in only trace amounts. The removals of the other metals varied considerably. No consistent conclusions can be made from the data; each metal, soluble or total fraction, and unit treatment operation must be interpreted individually. The only metal in the plant effluents consistently above the recommended limit was arsenic, and this barely above the limit. The only other metal present in the effluent above the recommended limit was the lead content from Fitchburg, despite 83% removal of this metal in the treatment system.
Removal of heavy metals in wastewater in a clay soil matrix using electro‐osmosis
Authors: Ray Chittaranjan , Ramsey R. H.
Published: February 2007

The feasibility of using electro‐osmosis for removal of heavy metals (Cd, Cu, and Pb) contained in aqueous solutions was examined using soil cores formed from Randall clay — a clay found in Playa lake basins in the High Plains of West Texas. Initially, sorption tests were conducted with the clay dispersed in the metal solutions of interest to determine if adequate sorption would take place. The retention capacity of the clay for Cd was found to be 0.0083 mg/mg of soil. (105 kilograms of Cd could be removed in top one‐meter depth of a hectare of Randall clay with a bulk density of 1.4 g/cm3).

Electro‐osmosis was found to increase the permeability of the clay but was found to be both a slow rate system (up to 225 days to remove one pore volume of water through a m3 of soil) and energy intensive (1.44 × 105 kJ to 8.1 × 105 kJ per m3 of drained water). Problems noted during the test that need solution before further experimentation with this procedure include selection of less corrodible materials for electrodes, prevention of electrolysis of water at potential gradients needed to move the waters being treated through the soil matrix, and control of ion gradients from the anode to the cathode reservoir to prevent backflow episodes from reversing flow from the cathode to the anode region.
H2S/SO2 removal in the modified‐claus reaction over packed alumina beds
Authors: Chou C.‐L. (Joe)
Published: February 2007

The removal of H2S and SO2 by the modified‐Claus reaction was studied in a computer‐controlled packed bed system over activated alumina catalyst. The reactor system consisted of two 6.35 × 60.96 cm reactors in parallel and was designed to allow for the axial temperature monitoring and side stream sampling. The H2S/SO2 conversion efficiencies were‐evaluated against gas‐hourly space velocity (GHSV) ranging from 100 to 12,000 1/hr at the three typical Claus converter conditions for three sizes of Alcoa S‐100 Claus catalyst. The conditions for defining the kinetic and thermodynamic regimes of the modified‐Claus reaction were reported. The thermodynamic regime was checked and confirmed by the equilibrium predictions of a computer program utilizing the principle of minimization of Gibbs free energy. The possible rate‐controlling mechanism in the kinetic regime and the effects of water vapor on the reaction were discussed.
Removal of dissolved organic contaminants by ozonation
Authors: Yurteri Coskun , Gurol Mirat D.
Published: February 2007

This article focuses on the use of ozone for the elimination of dissolved organic pollutants from water and wastewaters. The physical and chemical phenomena prevailing during the contact of a polluted liquid stream with gaseous ozone‐air or ozone‐oxygen mixture in empty or packed columns is represented mathematically. The simulation procedure is based on defining the concentration profiles of ozone and the organic solutes in both liquid and gas phases by means of differential mass balances. Methods for the determination of necessary model parameters is outlined and the model is analyzed for its sensitivity to various process variables.
Hazardous waste minimization and management at an R&D laboratory
Authors: Boortz M. J.
Published: February 2007

Chevron Richmond Research Center (RRC), located in Richmond, California, conducts research and technical service in the fields of petroleum and petrochemical products, processes, and related matters. To assure proper disposal of all wastes generated, RRC has implemented a unique waste disposal system. The system entails the use of specific disposal procedures and color‐coded waste receptacles for the different types of wastes. Communication with employees is vital for successful use of the waste disposal system. A written waste mangement plan documents the achieved and the projected reductions in wasted generation. Most of the hazardous waste reductions realized prior to 1989 were from installation of equipment and offsite recycling. Much of the future reductions are expected to come from changes in laboratory procedures and practices. The ultimate goal is to increase employee environmental awareness so that waste minimization is a routine part of every job.
Use of an air inflated dome to control VOC emissions from an aeration lagoon
Authors: Joffe Lawrence B.
Published: February 2007

In 1979, the Upjohn Company entered into negotiations with the State of Conecticut for renewal of their NPDES permit. During these negotiations, control of odors from the site became an issue, and several methods of eliminating potential odor sources from the facility were examined. At this point in time, the waste treatment system consisted of a series of lagoons, the last one being an aeration lagoon with two 150 horsepower fixed aerators. One of the many potential odor sources to be addressed was this lagoon. As part of the permit renewal conditions, the State of Connecticut DEP ordered Upjohn to construct an air supported enclosure over the 9,500–11,350 m3 aeration lagoon. Exhaust air was to be monitored and treated with the use of fixed bed granular activated carbon absorbers. This resulted in a project costing over $620,000 to construct and an additional $75,000–$100,000 per year to operate.
Bench–scale evaluation of calcium sorbents for acid gas emission control
Authors: Jozewicz Wojciech , Chang John C. S. , Sedman Charles B.
Published: February 2007

Calcium sorbents for acid gas emission control were evaluated for effectiveness in removing SO2/HCl and SO2/NO from simulated incinerator and boiler flue gases. All tests were conducted in a bench‐scale reactor (fixed‐bed) simulating fabric filter conditions in an acid gas removal process. Reagent grade Ca(OH)2 was used to establish baseline sorbent performance. The reactivity of reagent grade Ca(OH)2 with HCl from SO2/HCl mixtures gradually increased with decreasing approach to saturation temperature. SO2 reactivity toward Ca(OH)2 was very sensitive to approach to saturation. Novel calcium silicate sorbents were tested for reactivity with both SO2 and HCl. A “thermal window” for optimum NO removal was found at 90°C (194°F) when Ca(OH)2 was used at SO2/NO ratios of 1:1. Reactivity of Ca(OH)2 toward SO2 from SO2/NO mixtures was very sensitive to approach to saturation, while reactivity with NO was insensitive. Several additives were subsequently tested to determine optimum sorbent combinations for SO2/NO control. To date the most promising additives are Mg(OH)2 and Na2HPO4 at 10 mol percent concentrations. As with SO2/HCl, calcium silicate has been shown to be superior for SO2/NO capture. Some implications for larger‐scale process configurations and sorbent selection for HCl/SO2/NO control are discussed. Future activities and limited larger–scale pilot plant results are also discussed.