bluuebunny/crossref_metadata_2025 huggingface dataset:
Public health role, aluminium and Alzheimer's disease
Authors: Smith Lesbia F.
Published: February 2007

The recent literature has given considerable attention to the role of aluminium (Al) in Alzheimer's disease (AD) and to the possible etiological link of ingestion of aluminium from public drinking water supplies. Principles on prevention espoused by public health oblige it to define its role in modifying exposure to aluminium if such exposure is considered a significant risk factor in the causation of AD. Some researchers recommend public education about the suspected link between aluminium and AD, the labelling of food and other products for human use with the content of aluminium, and the reduction of aluminium in alum‐treated drinking water to less than 100 μg/l. Implementation of these recommendations could require significant changes in public health policy and in individual behaviour. AD is an important health problem. Any reasonable and practical measures which would prevent AD are worthy of public policy support. However, public health policy should be based on scientific information and not on speculation.
The ability of wet deposition networks to detect temporal trends
Authors: Oehlert Gary W.
Published: February 2007

We use the spatial/temporal model developed in Oehlert (1993) to estimate the detectability of trends in wet‐deposition sulphate. Precipitation volume adjustments of sulphate concentration dramatically improve the detectability and quantifiability of trends. Anticipated decreases in sulphate of about 30 per cent in the Eastern U.S. by 2005 predicted by models should be detectable much earlier, say, 1997, but accurate quantification of the true decrease will require several additional years of monitoring. It is possible to delete a few stations from the East without materially affecting the detectability or quantifiability of trends. Careful siting of new stations can provide substantial improvement to regional trend estimation.
Goodness‐of‐fit using very small but related samples with application to censored data estimation of PCB contamination
Authors: Johnson Richard A. , Gan D. Robert , Berthouex P. M.
Published: February 2007

Many environmental data sets contain observations which are below the method or instrumental limit of detection which are often referred to as ‘censored data’. These censored data create great uncertainties in the data analysis for the environmental quality management. It is necessary to quantify these uncertainties in order to determine compliance, or non‐compliance, with relevant environmental quality standards, to estimate the parameters used in assessment models, and to monitor the environmental quality. The analyses for data sets that contain censored data are not new, but most distribution free methods require large sample sizes. For a data set containing censored observations with a small size, e.g. n = 3, which is typically observed for environmental samples, distribution free techniques will fail to provide reasonable answers due to the tremendous uncertainties in the analysis. This paper is proposed to demonstrate one approach which could be used to analyse environmental data sets with small sample sizes. If a distribution is known to be normal, or log‐normal, optimal estimates are easily obtained. In the scientific investigation that motivated this study, at most three observations are available. We address two statistical questions. The first concerns normality. If all the populations are normal, even with different means and variances, we can obtain an overall check of fit. To do so, we propose to calculate the correlation between the three order statistics and the normal scores. The distribution of the whole set of correlations is then compared to what it would be if all of the populations are normal. Secondly, we consider transformations of the original observations and illustrate how our goodness‐of‐fit procedure can be used to select a transformation.
Imputation of missing values in spatio‐temporal solar radiation data
Authors: Glasbey C. A.
Published: February 2007

Solar radiation was measured almost every 10 minutes for 2 years at ten sites in the Pentland Hills to the south of Edinburgh. A few values were missing because of instrument failure or because the data logger was occupied in data transfer. Two ad hoc methods for replacing the missing values are compared by cross‐validation. It is found to be better to interpolate sequences of up to four missing values, and the first and last missing values in longer sequences, using data from the same site, but otherwise it is better to average synchronous data from the other nine sites. A spatio‐temporal model of the second‐order moments of the data is identified and used to specify optimal linear predictors based on both within‐ and between‐site data.
Turbulent dispersion and the beta distribution
Authors: Chatwin P. C. , Lewis D. M. , Sullivan Paul J.
Published: February 2007

Some recent research on the properties of the probability density function for the concentration of a scalar dispersing in turbulent flow is summarized. It is concluded that the beta distribution may be a simple model consistent with these properties. This proposal is verified theoretically, and some preliminary data comparisons are very promising.
Uncertainties in lung cancer risk estimates reported for exposure to environmental tobacco smoke
Authors: Gross Alan J.
Published: February 2007

The United States Environmental Protection Agency (EPA), in its recent risk assessment dealing with environmental tobacco smoke (ETS), estimated the annual number of lung cancer deaths in non‐smokers (including both never‐smokers and former‐smokers who have quit smoking for at least five years) associated with ETS exposure to be between 2500 and 3300 in the United States. This estimate is based on a number of assumptions that are not supported by the existing data. Moreover, the range presented by EPA fails to take into account the uncertainties involved in this estimate. This paper discusses the significant assumptions that underlie any quantitation of lung cancer risks allegedly due to ETS exposure, and explores the uncertainties of each assumption and how each uncertainty affects the summary estimate. The author concludes that any range must encompass an estimate of zero deaths, and that the uncertainties are so great as to cast serious doubt on the use of any quantitative estimate.
The α‐β model for concentration moments in turbulent flows
Authors: Mole Nils
Published: February 2007

Chatwin and Sullivan (1990a) proposed a simple model (in terms of two parameters α and β) for the moments of scalar fluctuations in self‐similar turbulent shear flows. They showed the model results to be well satisfied by observations from a range of experiments. Here their theory and some developments from it are summarized. The latter include results on the relationships between higher moments, in particular the skewness and kurtosis, and models for the evolution of α and β.
A generalized pareto distribution model for high concentrations in short‐range atmospheric dispersion
Authors: Mole N. , Anderson C. W. , Nadarajah S. , Wright C.
Published: February 2007

Generalized Pareto distribution (GPD) models are fitted (by maximum likelihood) to extreme concentrations in a set of atmospheric dispersion experiments. QQ plots, together with simulations to provide an objective measure of goodness of fit, are used to show that these models fit the data well. It is found that in some cases a model in which the GPD parameters vary with time, in particular in a periodic manner, gives a significant increase in the likelihood over that for the model with constant parameters. Predicted return levels decrease with increasing downwind distance from the source. They are also higher in the experiments in stable conditions than in those in convective conditions, although it is argued that this might well not have been the case had the duration of the stable experiments been greater.
Modelling the evolution of moments of contaminant concentration in turbulent flows
Authors: Clarke Liz , Mole Nils
Published: February 2007

Sullivan and Moseley developed a model for the evolution of concentration moments in turbulent flows. It utilized Chatwin and Sullivan's α‐β model and the space‐integrated advection‐diffusion equation with a closure assumption. The resulting model gave generally realistic results in one spatial dimension, but gave less satisfactory results in two and three dimensions. Here this is shown to be associated with a singularity in the equations which is independent of the closure assumption. However, the singularity occupies a non‐physical region of the phase space, and an alternative closure is presented which avoids this region and yields physically realistic solutions in one, two and three dimensions.
Calibration error and the measurement of turbulence statistics
Authors: Derksen R. W.
Published: February 2007

This paper demonstrates an application of the maximum entropy method to the estimation of the uncertainty due to calibration in the measurement of the moments of turbulent probability density functions. Specific examples are drawn from nominally linear transducers and hot‐wire anemometry.
Turbulent diffusion as a stochastic lagrangian process
Authors: Rodean Howard C.
Published: February 2007

The present status of stochastic Lagrangian models of turbulent diffusion is reviewed, beginning with a brief historical introduction. The mathematical and physical foundations of these models are described. The derivation of the model for the Lagrangian trajectory of a single particle is illustrated for one‐dimensional inhomogeneous Gaussian turbulence. Single‐particle models for non‐Gaussian turbulence in the convective boundary layer are described. The mean concentration in fixed co‐ordinates is calculated from the statistics of thousands of single‐particle trajectories. Another class of stochastic Lagrangian models gives the relative dispersion of particle pairs and the concentration variance. A list of references is provided for further study.
Statistical fluctuations due to microscale mixing in a diffusion layer
Authors: Zimmerman William B. , Chatwin P. C.
Published: February 2007

A new viewpoint on the evolution of scalar dispersion in a turbulent flow is taken by considering diffusion of a passive scalar where the measuring device is stochastically positioned. This is a model of a dispersion process where mixing at small scales occurs by molecular diffusion and large scale motions are rigid in regards to the internal cloud structure. Numerical results for the first four central moments are presented, and are shown to be consistent with theoretical approximations for both small and large times. The plot of kurtosis against skewness collapses onto a quadratic curve close to those discussed by Mole and Clarke, and others. The present work suggests that this robust feature has a rather simple basis in physics, and further research is proposed that will critically test this interpretation.
Statistics and the environment: The analysis of large‐scale earth‐oriented systems
Authors: Thiébaux H. Jean
Published: February 2007

The focal point of this paper is the concept: the environmental unit is Earth itself. To analyze and predict global environmental phenomena, the dimensions of our domain of concern must match those of the planet's dynamic fluid envelope: atmospheric and oceanic. Traditional techniques of statistical diagnostic analysis and prediction must be cast in the natural coordinates of earth‐oriented systems and computer technology tasked to its present limits to handle global scale data bases.

A notation is presented in which various approaches to estimating variables in large domains can be seen as adaptations to a common estimation objective. Their differences arise from differences in the scope and extent of information available to describe the system under study. The “universal estimator notation” serves to identify areas for significant further development. Examples are given which illustrate the potential impacts on spatial estimation algorithms of using available data to tune them to location and current state.
An examination of the lognormal and box and cox family of transformations in fitting environmental data
Authors: Stoline Michael R.
Published: February 2007

This paper investigates the fit of the lognormal model and Box and Cox (BC) family of transformation models to several data sets that arise in environmental contexts where the data may be heavily left‐censored with multiple detection limits. A model fitting protocol is described that selects an optimal BC model, identifies outlying observations, and verifies the final model using a normal probability plot correlation statistic. This protocol is used to fit these models to data collected on seventeen groundwater chemistry variables in Ingham County, Michigan in 1986‐1987 as part of the Michigan Groundwater Survey. Six of these variables are adequately modelled by an optimally‐chosen BC model and five of these six are adequately modelled by the lognormal model. Ten of the study variables are marginally modelled by a BC model, whereas only six of the study variables are marginally fit by the lognormal model. The remaining variables fail the fitting criteria due to the significance of the probability plot correlation statistic or because of the presence of outlying observations in the final model.

On the basis of these results, the data analyst is cautioned against the automatic use of the lognormal model for fitting environmental data in every circumstance. What is recommended is checking the adequacy of the lognormal model prior to use. If the lognormal model is not an adequate model, then perhaps some other member of the Box and Cox family will provide an adequate model.
Determination of sample size during ongoing sampling
Authors: Violato Claudio
Published: February 2007

An empirical technique for determining sample size during ongoing, non‐probability, haphazard sampling is described in the present paper. While there are many techniques for determining sample size a priori, all of them require a knowledge of the population parameters (or at least their variance). Moreover, these a priori methods are based on assumptions of probability sampling such as simple random, stratified random, cluster, and so on. It is common in psychological, biological, social, environmental and medical research, however, to employ non‐probability samples of unknown representativeness and with virtually no knowledge of the parameters in question. Thus a priori techniques are quite impractical and limited in their usefulness.

The procedure described in the present paper is an empirical method which does not require assumptions of probability sampling. The method involves determining the point of convergence of Sums of Squares and Cross Products (SSCP) matrices in sequential sampling using Wilk's lambda as a criterion with Rao's approximate F as a test statistic. When the SSCP matrices of two sample sequences converge at the α = .10 level of significance, the sample size is determined to be adequate as the estimators have stabilized. Further sampling would produce redundant data. An application of the present technique to a large scale study is given as a practical example.
Estimation of the LC50, a review
Authors: Hoekstra J. A.
Published: February 2007

In this paper methods to estimate the median lethal concentration (LC50) are reviewed. Estimation from data sets with limited occurrence of partial response (>0%, <100%) receives particular attention.
Trend detection in the presence of covariates: Stagewise versus multiple regression
Authors: Smith Eric P. , Rose Kenneth A.
Published: February 2007

The assessment of trend in environmental quality is an important task for environmental managers and scientists. Much recent research has focused on the proper methodology for the assessment of trend, for example, when the data are correlated or censored. An equally important problem is discussed in this paper, that of the specifying underlying models that relate the environmental quality time series to other time dependent covariates and how to adjust for these covariates. Two basic approaches for the adjustment for covariates are stagewise regression and multiple regression. We use simulation, analysis and a data set from the Chesapeake Bay, U.S.A., to show that the approach based on stagewise regression can yield misleading results. We show that the multiple regression approach is generally more powerful than the stagewise method.
Use of robust methods in the analysis of suspended particulate air pollution: A case study in Malaysia
Authors: Abdullah Mokhtar , Sani Sham
Published: February 2007

This paper describes several analyses in which a robust method, namely the least median of squares (LMS) has been used in the development of a mathematical model to relate suspended particulate air pollution concentration to meteorological factors. The robust procedure provides a formal method that not only pays due attention to anomalies or outliers in the data but also reduces the influence of the outliers. The study showed that the robust procedure yielded more reliable results than did the classical least squares (LS) approach.
Non‐parametric trend test of baltic sea data
Authors: Sandén P. , Rahm L. , Wulff F.
Published: February 2007

The recently reported tendencies toward decreasing total amounts of silicate in the Baltic Sea are investigated by use of non‐parametric trend analysis. The period 1968‐1986 showed significant falling trends in surface waters from the whole system. The deepest parts of the Baltic proper did in contrast reveal strong increasing trends. These trends are more pronounced during the latter part of the analysis period which is characterized by stagnant conditions in the Baltic proper. These conditions have been prevailing since the major inflow in 1976. The causes of the observed changes are unclear. The increased load of nutrients and accompanying increase in primary production is, however, one factor. Another is coupled to the stagnation conditions of the Baltic Proper.
Inverse sampling in case control studies
Authors: Singh Padam , Aggarwal Abha Rani
Published: February 2007

In case control studies when the relative risk is very high the expected frequencies of diseased but not exposed and non‐diseased but exposed are generally very low. In such situations inverse sampling can be used. This paper presents the relevant theory of inverse sampling in case control studies. The expressions for bias and Mean Square Error (MSE) have been derived. It has been observed that the estimator under inverse sampling is unbiased and more efficient as compared to the estimator under usual case control studies.
A search for the source of the nile's change‐points
Authors: Macneill I. B. , Tang S. M. , Jandhyala V. K.
Published: February 2007

The annual discharges of the Nile River at Aswan are examined for change‐points in both mean level and in serial correlation structure. The methodology used identifies 1899 as a change‐point for the mean level; this has been observed by others. Second and third change‐points for the mean level are identified at 1954 and 1965. In addition, a change is observed in the serial correlation structure of the detrended series. For the segment prior to 1907 this structure is compatible with white noise; after 1907 it is characterized by strong serial correlation and is closely modelled by an ARMA(2,2) model. This serial correlation is taken into account when identifying the 1954 and 1965 changes in mean level.

The history of the Nile basin is examined for significant hydrological and political events that might be connected with these change‐points. It is speculated that the changes in mean level at 1899 and 1954 and in serial correlation structure are changes in the data due to measurement and hydropolitical issues. A competing hypothesis for the cause of changes in mean level involves long‐term climatic shifts that could be modelled by long‐memory or doubly stochastic models.
Encountered data, statistical ecology, environmental statistics, and weighted distribution methods
Authors: Patil Ganapati P.
Published: February 2007

We have begun to experience in data gathering and analysis in modern ecological and environmental work a space age/stone age syndrome. Also we are challenged to break into the cycle of no information, new information, and non‐information while dealing with soft data, hard looks, and prudent decision‐making involving errors of the third and the fourth kind in addition to those of the first and the second type.

Weighted distribution methods arise in the context of data gathering, modeling, inference, and computing, and help provide a unified approach in dealing with encountered data.
In‐situ biodenitrification of the S‐3 ponds
Authors: Napier J. M. , Bustamante R. B.
Published: February 2007

A process has been developed for removing nitrates and heavy metals from open ponds. Four ponds were treated using the developed process. The process steps involved neutralization of the ponds, followed by biological denitrification. The nitrate ions were reduced from 40,000 mg/L to <50 mg/L at an average denitrification decrease rate of 300 mg/L per day. The denitrified water was then flocculated and filtered to remove solids. The water quality met discharge water chemical limits as well as biological test requirements.
Control of emissions from an air stripper treating contaminated groundwater
Authors: Byers W. D.
Published: February 2007

The performance and costs of two well water treatment systems are compared: an aqueous‐phase granular‐activated‐carbon (GAC) system, and an air stripping system with emission control. Both systems were installed to remove volatile organic compounds (VOC's) from the Verona Well Field, which supplies potable water to Battle Creek, Michigan.
Recovery of volatile organics from small industrial sources
Authors: Spivey James J.
Published: February 2007

The recovery of volatile organic compounds (VOCs) from contaminated air generated by small industrial operations such as coating operations and spray painting is an important alternative to other air cleaning techniques such as thermal or catalytic incineration. Three technologies—adsorption, absorption, and condensation—are discussed herein. The focus of this article, and by far the most widely applied technique, is activated carbon adsorption. Commercial systems are generally designed for gas streams containing roughly 300 to 5,000 ppm VOC at flow rates from 200 to 100,000 ft3 (STP)/min (5.7 to 2,830 m3 (STP)/min).

General design parameters and costs, along with their application to example cases, are given for VOC recovery by activated carbon adsorption and condensation. No commercial systems specifically for VOC recovery by absorption have yet been reported, though this technology is extremely important for other air pollution control needs.
Heterogeneous ozonation kinetics of pollutants in wastewater
Authors: Whitlow J. E. , Roth J. A.
Published: February 2007

Ozonation is a technically viable wastewater treatment alternative for achieving stringent effluent limitations. Limited feasibility data have been reported in the literature on a wide range of pollutants. These data are primarily time concentration profiles for semi‐batch air‐ozone or oxygen ozone gas phase contacting with pollutant‐water systems. These data have been evaluated and correlated where possible in correlations of a form suitable for scaleup to continuous systems. Pollutants include ammonia, phenol, styrene and cyanides.
Evaluating potential impacts from accidental gaseous releases of toxic chemicals
Authors: Heinold David , Smith Douglas , Schwab Bradley
Published: February 2007

Many companies involved with toxic gases are seeking an independent evaluation of liability in the event of an accidental release. A detailed methodology is presented with a hypothetical example based on case studies from several recent risk assessments. These demonstrate such typical components of an analysis as site reconnaissance, accident scenario development, air quality assessment, health impacts potential and remedial action review.
Development of options for minimizing hazardous waste generation
Authors: Drabkin Marvin , Fromm Carl , Freeman Harry M.
Published: February 2007

The U.S. EPA is encouraging hazardous waste generators to develop programs to reduce the generation of hazardous waste. To encourage such programs the Agency's Hazardous Waste Engineering Research Laboratory is supporting the development and evaluation of a model hazardous waste minimization audit procedure. The procedure was tested in several facilities during the summer of 1986.
Alternatives for reducing the risks of hazardous material storage facilities
Authors: Hendershot Dennis C.
Published: February 2007

Because they contain relatively large inventories, hazardous material storage facilities often represent a major contribution to the overall risk from a chemical manufacturing facility. Application of basic chemical engineering principles to the problem of reducing or eliminating the consequences of a release can identify means to substantially reduce the intrinsic hazards of such facilities. Also discussed are examples of possible approaches, including material substitution, inventory reduction, dilution, and refrigeration.
Hydrogenation and recycle of organic waste streams
Authors: Kalnes T. N. , James R. B.
Published: February 2007

Each year, billions of gallons of organic waste liquids are generated. Recently implemented EPA regulations now provide an economic driving force to minimize the net production of these waste materials. A hydrocarbon refining process employing catalytic hydrogenation has been expanded from current petroleum and petrochemical applications to the treatment and recycle of hazardous organic waste streams. In this paper, three classes of hazardous organic wastes are studied: PCB insulating liquids, halogenated petrochemical by‐products, and residue from distillate oil sulfuric acid treatment. Pilot plant data are presented as the basis for evaluating the environmental and economic advantages of hydrogenation and reuse.
Economic evaluation of waste minimization options
Authors: Karam Joseph G. , Cin Carl S. T. , Tilly Jean
Published: February 2007

Three analytical tools developed to assist hazardous waste generators in identifying and evaluating the economic feasibility of waste minimization options are presented. Ranging in scope and sophistication from comprehensive financial analysis models to simple data management systems, these analytical tools are: a financial analysis model; a multi‐option model (MOM); and a future liability assessment model.
Opportunities for research in hazardous waste minimization
Authors: Kosson David S.
Published: February 2007

Hazardous waste minimization programs are currently under development throughout the country. This paper discusses the options currently being considered in the state of New Jersey and the gaps in knowledge that must be resolved prior to implementation of an effective waste minimization policy.
Absorption, electrodialysis, and additional regeneration in two flue gas SO2/NOx cleanup processes
Authors: Walker Richard J. , Pennline Henry W.
Published: February 2007

Two new processes that can each simultaneously remove sulfur dioxide (SO2) and nitrogen oxides (NOx) from flue gas by wet scrubbing with a liquor that contains an SO2‐removal agent and a metal chelate for NOx removal are described. They are similar, except for different by‐products. In both, the spent scrubbing liquor is regenerated with respect to sulfur by an electrodialysis stack employing cation‐ and anion‐selective membranes. Sulfate salts are produced as by‐products. Experimentally, the liquor has been regenerated with respect to NOx removal ability by holding it at elevated temperature, but the mechanism is not well understood.
Evaluation of control strategies for volatile organic compounds in indoor air
Authors: Ramanathan Kumar , Debler Vickie L. , Kosusko Michael , Sparks Leslie E.
Published: February 2007

The Air and Energy Engineering Research Laboratory of the U.S. Environmental Protection Agency (U.S. EPA) conducts and sponsors research on technology to reduce or eliminate emissions of potentially toxic volatile organic compounds (VOCs) from industrial/commercial sources.

The realization that indoor air environments, where humans spend the majority of their time, also contain significant levels of VOCs has led to a number of EPA‐sponsored studies on monitoring, modeling, and controlling these compounds. The purpose of this paper is twofold: to present an overview of the problem of indoor air pollution by VOCs and approaches to solving it, and to report the results of a study to determine the feasibility of carbon adsorption for control of VOCs in indoor air.
Indoor radon: Source characterization
Authors: Kunz Charles O.
Published: February 2007

Sources for indoor radon including radon from soils and rock infiltrating the substructure of a home and radon from water usage, building materials, outside air, and burning natural gas are reviewed. It is generally accepted that radon from soils and rock is the principal source for indoor radon. Correlations between indoor radon levels and soil characteristics are discussed for six areas in New York State. These results indicate that soils can be characterized for radon availability and transport into homes by a combination of soil parameters including the source strength (soil radium concentration or soil‐gas radon concentration), soil permeability for gas flow and, depth of soils to bedrock or water table.
Electrophysical sorption of single carbon halogenated solvents onto soil
Authors: Mokrauer J. E. , Kosson D. S.
Published: February 2007

Sorption of halogenated single carbon organic contaminants onto a sandy loam has been found to be controlled by the electrostatic attraction between a slightly negatively (δ−) charged clay particle and a positively (δ+) charged carbon atom within the solvent molecule. Adsorption isotherms for chloroform, bromodichloromethane and methylene chloride indicate that the extent of sorption appears to have a direct functional relationship to the molecular charge distribution within the solvent molecule, and to the atomic radii of the molecular substituents of the contaminant. When a carbon atom is saturated with highly electronegative substituents (e.g. carbon tetrachloride), an electron cloud surrounds the molecule and shields the slightly positive (δ+) carbon nuclei. This shielding effect limits the sorption that occurs. A study on carbon tetrachloride sorption resulted in no detectable sorption onto the sandy loam soil. This theory of adsorption is defined as Electrophysical Sorption (EPS) because it reflects the combination of electrostatic and physical contributions to sorption.
Destruction of aromatic pollutants by UV light catalyzed oxidation with hydrogen peroxide
Authors: Sundstrom D. W. , Weir B. A. , Klei H. E.
Published: February 2007

Toxic and hazardous compounds are often present in water at low concentrations, which can make their removal difficult and costly by conventional treatment processes. A promising method for destroying pollutants in water is ultraviolet (UV) catalyzed oxidation by hydrogen peroxide. The effectiveness of this process was determined for typical aromatic compounds including benzene, toluene, chlorobenzene, phenol, 2‐chlorophenol, 2,4‐dichlorophenol, 2,4,6‐trichlorophenol, dimethyl phthalate, and diethyl phthalate. The reactions were conducted in a quartz annular reactor equipped with a low‐pressure mercury lamp. Of the aromatics studied, reaction rates were fastest with 2,4,6‐trichlorophenol and slowest with the phthalates. Analyses of reacted samples by HPLC and GC/MS indicated that the aromatics formed many intermediates that could be destroyed by extending the treatment time. An empirical rate expression was developed to correlate the results.
Process selection criteria for the biological treatment of industrial wastewaters
Authors: Eckenfelder W. W. , Argaman Y. , Miller E.
Published: February 2007

This paper illustrates some of the principles that lead to a rational selection of a biological treatment process for industrial wastewaters.
Two strategies for PCB soil remediation: Biodegradation and surfactant extraction
Authors: McDermott John B. , Unterman Ronald , Brennan Michael J. , Brooks Ronald E. , Mobley David P. , Schwartz Charles C. , Dietrich David K.
Published: February 2007

Two strategies for the cleanup of PCB‐contaminated soils are being developed: biodegradation by selected bacteria and extraction with aqueous surfactant solutions. Extensive biodegradation has been demonstrated by Pseudomonas putida strain LB400 in studies with Aroclor‐spiked laboratory soil and soil from a New York State site containing 525 ppm of transformed Aroclor 1242 (depleted of di‐ and trichlorobiphenyls). Solutions of sodium dodecylbenzenesulfonate can extract PCB from soils. A bench‐scale process with four countercurrent stages effected the cleanup of a heavy clayey soil. The PCB was recovered from the surfactant solution by precipitation with calcium chloride, reducing the mass of contaminated material to 3% of the original soil mass.
Fundamental experiments on thermal desorption of contaminants from soils
Authors: Lighty Joann S. , Silcox Geoff D. , Pershing David W. , Cundy Vic A. , Linz David G.
Published: February 2007

The goals of this research are to develop an understanding of the transport phenomena that occur during the desorption of contaminants from soil and to obtain rate information. This information can then be used to develop a model to predict the performance of full‐scale thermal treatment systems for optimization and cost reduction.
Waste treatability tests of spent solvent and other organic wastewaters
Authors: Turner Ronald J.
Published: February 2007

Some commercial and industrial facilities treat RCRA spent solvent wastewaters by steam stripping, carbon adsorption, and/or biological processes. Thirteen facilities were visited by EPA's Office of Research and Development (ORD) from June 1985 to September 1986, to conduct sampling and analysis episodes and to determine the levels of performance achievable by these and other treatment processes. This paper summarizes the results of five of the tests: two steam strippers, two carbon adsorption systems, and one activated sludge biological system.
Improved clarifier performance and capacity through the use of a flow contraction baffle
Authors: Silveston Peter L. , Hudgins Robert R.
Published: February 2007

Pilot‐scale tests were conducted over several years on the effectiveness of a flow contraction baffle installed in a pilot‐scale clarifier to separate solids from both primary sewage and activated sludge mixed liquor. Tests used two matched, 1.2‐m diameter clarifiers, one of which was fitted with the baffle, in the form of a truncated cone descending from the effluent weir. Effectiveness of the flow contraction baffle results from the suppression of additive interference of density waves always present in clarifiers as well as provision for the uniform withdrawal of the clarified liquor.
Low temperature thermal treatment (LT3) of volatile organic compounds from soil: A technology demonstrated
Authors: Nielson Roger K. , Cosmos Michael G.
Published: February 2007

Weston has developed, tested, demonstrated, and operated a transportable system to remove, through evaporation, and subsequently destroy volatile organic contaminants in soil and sludges. The process is called Low Temperature Thermal Treatment (LT3). The purpose of this patented process is to restore the soil to its original condition, making it suitable for on‐site backfill and to eliminate the long term liability and potential costs associated with off‐site transportation and disposal.
Incineration of solid waste
Authors: Lee C. C. , Huffman George L.
Published: February 2007

The concern over solid waste disposal and dump‐site clean‐up resulted in the passage of three major U.S. environmental laws. They are the Resource Conservation and Recovery Act (RCRA) of 1976, Public Law 94–580, the Toxic Substances Control Act (TSCA) of 1976, Public Law 94–469, and the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) of 1980, Public Law 96–510. The implementation of these three laws has intensified incineration research, because incineration represents the highest degree of destruction and environmental control possible for various waste types. This paper reviews the fundamentals of incineration and provides an incinerator design example to show how combustion fundamentals are applied to an incineration system.
Relationships between laboratory and pilot‐scale combustion of some chlorinated hydrocarbons
Authors: Chang Daniel P. Y. , Sorbo Nelson W. , Law Chung King , Steeper Richard R. , Richards Marta K. , Huffman George L.
Published: February 2007

Factors governing the occurrence of trace amounts of residual organic substance emissions (ROSEs) in full‐scale incinerators are not fully understood. Pilot‐scale spray combustion experiments involving some liquid chlorinated hydrocarbons (CHCs) and their dilute mixtures with hydrocarbons (HC) were undertaken at the USEPA's Center Hill Laboratory. Individual droplet‐burning characteristics of CHCs and HCs were also studied at the University of California, Davis on a more fundamental level to isolate and identify potentially important phenomena. The practical implications of the experimental observations on incinerability ranking, formation of ROSEs, and strategies for reducing ROSEs are discussed.
Physical properties and chemical species distributions within municipal waste combuster ashes
Authors: Ontiveros J. L. , Clapp T. L. , Kosson D. S.
Published: February 2007

Incineration of municipal solid waste has been viewed as a preferred alternative to landfilling in recent years. Fly ash and bottom ash are of particular concern because of the high concentration of heavy metals on and within the ash matrix. This paper presents chemical, physical, and structural properties of the ashes from several municipal waste combustors. Properties of both the bulk ash and ash fractions separated by particle size are included. Results have shown significant variability based upon both ash type and particle fraction.
Exposure and risk assessment for a proposed hazardous waste incinerator
Authors: Tilly Jean , Dietrich Gary , Pyne Dan
Published: February 2007

In supporting a firm's application for a Part B permit to operate a hazardous waste incinerator in Rhode Island, an exposure/risk assessment was conducted estimating: the maximum concentrations associated with the emissions of hazardous constituents from the incinerator; and the risks due to the exposure to these concentrations. This included determining the probability of the Most Exposed Individual (MEI) developing a cancer case and the number of cancer cases that may develop within a 50‐km radius of the proposed incinerator.
Continuous recovery of heavy metals from MSW incinerator ashes
Authors: Legiec I. A. , Hayes C. A. , Kosson D. S.
Published: February 2007

The leachable concentrations of heavy metals from ash residues from the incineration of municipal solid waste (MSW) often exceeds the Extraction Procedure Toxicity Test (EP Tox) limits, requiring these materials to be considered as a potential hazardous waste. The kinetics of Pb, Cd, and Cr extraction were determined through a series of batch extraction studies. The specific incinerator design and the equilibrium conditions strongly influenced the ash matrix and subsequently the extraction kinetics. Recovery of the metals from the extractant solution was accomplished utilizing electrochemical plating techniques.
Liquid redox sulfur recovery options, costs, and environmental considerations
Authors: Dalrymple Dennis A. , Trofe Timothy W. , Evans James M.
Published: February 2007

Liquid redox chemistry has been employed for sulfur removal and recovery applications since the 1950's. The first process was the Stretford process, which was used commercially in the United Kingdom in the 1960's as a replacement for the iron sponge process in the treatment of sour town gas. The Stretford process has been joined in the United States' marketplace by several other liquid redox processes including the Unisulf, Sulfolin, LO‐CAT, SulFerox, and Hiperion processes. This paper describes the chemistry and engineering options available with each process, as well as the environmental and cost considerations associated with these processes.
Soil gas survey techniques for the investigation of underground storage tanks
Authors: Schlender Michael H. , Rowe Jerry
Published: February 2007

The sampling and analysis of near surface soil gas has shown great promise for the investigations of underground storage tanks. Trace to elevated concentrations of volatile organic components in soil gas samples have been used to identify source areas near buried tanks and map the migration of releases in groundwater and in the vadose zone. Soil gas surveys are also an effective tool to position soil borings, excavations, and monitoring wells, while support equipment (drilling rigs, backhoe, etc.) is still on site. Two examples are presented where soil gas surveys were used to direct the investigation of underground storage tanks.
Oil recovery and waste reduction by microwave radiation
Authors: Fang C. S. , Lai Daniel M. C. , Chang Bruce K. L. , Klaila W. J.
Published: February 2007

Oil‐in‐water and oil‐water‐solid emulsions, by‐products of various industrial operations, often are environmental concerns. Laboratory and field tests have shown that these emulsions can be demulsified and separated into their individual layers by microwave radiation. The data also show that microwave separation is faster than gravity separation and can be faster than conventnal heating at many conditions. After separation of emulsion into water, slop and oil layers, water can be discharged and oil is collected for recycle. The volume of slop is much smaller than the original volume of emulsion, therefore, the oily waste to be disposed is greatly reduced.

The zeta potential of oily droplets in water was measured and found that it is reduced by microwave radiation. This indicates that microwave provides heating and reduction of zeta potential in demulsification.
Effluent treatment for alcohol distillery: Thermal pretreatment with energy recovery
Authors: Lele S. S. , Rajadhyaksha P. J. , Joshi J. B.
Published: February 2007

Stillage from cane molasses based alcohol distillery was thermally treated at 160 to 250°C at high pressure and in the absence of air. A solid charred residue was precipitated that was easily separated by gravity filtration from a liquid suitable for anaerobic digestion or wet oxidation. The charred residue was comparable with typical lignite coal in terms of carbon content and calorific value. Effects of temperature and pH on COD reduction, biodegradability, and filterability were studied.
Bench‐scale testing of high‐temperature desulfurization sorbents
Authors: Gangwal S. K. , Harkins S. M. , Woods M. C. , Jain S. C. , Bossart S. J.
Published: February 2007

Extrudates of regenerable mixed‐metal oxide sorbents including zinc ferrite, copper‐modified zinc ferrite, and zinc titanate were prepared and tested for their potential to remove hydrogen sulfide (H2S) from coal gasifier gas in a high‐temperature high‐pressure (HTHP) fixed‐bed reactor. Reductions in H2S concentration from > 10,000 parts per million by volume (ppmv) to < 1 to 50 ppmv were achieved depending on sorbent, reactor temperature, and steam concentration. Zinc ferrite showed no apparent loss in capacity over 15 sulfidation‐regeneration cycles, but underwent significant strength reduction at 5% steam due to soot formation. Zinc titanate exhibited excellent strength and capacity retention at 5% steam and temperatures up to 735°C.
Pressure swing adsorption for VOC recovery at gasoline loading terminals
Authors: Pezolt Daniel J. , Collick Scott J. , Johnson Herbert A. , Robbins Lanny A.
Published: February 2007

Volatile organic compound (VOC) emissions from gasoline storage and distribution facilities are coming under increased scrutiny in both the United States and Europe. The recently passed European Community stage 1 directive for gasoline emissions has established an emissions limit of 35 grams total organic compounds (TOC) per cubic meter gasoline loaded (35 g TOC/m3). Similarly, the United States Environmental Protection Agency Standard 40 CFR Part 63 has established an emission limit of 10 mg TOC per liter of gasoline loaded (10 g TOC/m3). The German TA‐Luft standard, the most stringent known gasoline emission regulation, has set an emissions limit of 150 mg TOC (excluding methane) per cubic meter of loaded product (0.15 g TOC/m3).

The Dow Chemical Company has successfully applied the SORBATHENE

Registered Trademark of Radian International LLC.

Solvent Vapor Recovery Unit technology, a pressure swing adsorption process, to meet these increasingly stringent gasoline and light hydrocarbon vapor emission standards. Working through technology licensees (Radian International LLC, Austin, Texas and McTay Engineering, Bromborough, United Kingdom), a field trial demonstrating 99+% recovery efficiencies has been conducted at a major U.S. gasoline, storage and distribution terminal, and the first commercial SORBATHENE gasoline vapor recovery unit has been installed at a major storage and distribution terminal in Leeds, United Kingdom.
An experimental study of flue gas desulfurization in a pilot spray dryer
Authors: Ollero Pedro , Salvador Luis , Cañadas Luis
Published: February 2007

More than 45 experimental tests have been conducted on a 10,000 Nm3/h spray‐drying desulfurization pilot plant. The effects of SO2 and fly ash concentration, Ca/S ratio, approach to saturation temperature, unit load changes, and the utilization of seawater as make‐up water on both spray dryer behavior and treated flue gas properties were analyzed. This experimental study allows us to reach some conclusions about how to achieve optimum operating conditions and to assess the impact of spray drying on a downstream ESP.
DuPont soil washing technology program and treatment of arsenic contaminated soils
Authors: Legiec I. A. , Griffin L. P. , Walling P. D. , Breske T. C. , Angelo M. S. , Isaacson R. S. , Lanza M. B.
Published: February 2007

This paper summarizes a case study involving a site with inorganic arsenic‐contaminated soils. Detailed soil characterization studies involving sequential extraction testing indicated that the arsenic was primarily associated with the organic fraction and the iron oxide/manganese oxide fraction of the soil. A preliminary treatability study demonstrated that adequate leaching of arsenic was possible. Alkaline leaching was specific for arsenic. Future plans include a program of bench‐scale treatability and field pilot studies focusing on soil washing technology application.