bluuebunny/crossref_metadata_2025 huggingface dataset:
Spatial modelling of snow water equivalent using airborne and ground‐based snow data
Authors: Carroll Steven S. , Day Gerald N. , Cressie Noel , Carroll Thomas R.
Published: February 2007

As the population and industrial infrastructure of the United States continue to grow, the demand for water and the need to forecast water resources accurately are intensifying. Hence, the National Weather Service maintains a set of conceptual, continuous, hydrologic simulation models used to generate extended streamflow predictions, water supply outlooks and flood forecasts that are the basis for major water management and disaster emergency services decisions for the United States. A vital component of the hydrologic simulation models is a snow accumulation and ablation model that uses observed temperature and precipitation data to simulate snow cover conditions. The simulated model states are updated throughout the snow season using snow water equivalent estimates obtained from airborne and ground‐based snow water equivalent data. The National Weather Service has developed a spatial model to obtain integrated snow water equivalent estimates for updating the snow model; however, it is designed to incorporate only ground‐based data. In this research, we describe the spatial model and show how to modify it to include data of two different supports (the airborne and ground‐based data) so that more precise integrated snow water equivalent estimates can be obtained. The results are illustrated on snow data collected in the Upper Colorado River basin.
Metabolic responses in the assessment of pollution effects
Authors: Pires Ana , Branco Joao , Picado Ana , Mendonça Elsa
Published: February 2007

Adenylate nucleotide concentrations in the polychaete Lanice conchilega were measured and the index adenylate energy charge (AEC) was calculated at different times of the year. The organisms were sampled at three sites in the Sado River estuary, two of them located near the outfall of a pulp mill effluent and a third one in the south bank, considered as reference. A statistical analysis was conducted on the resulting observations in order to evaluate the site influence. Significant differences were found on the AEC values between more and less polluted sites. Another index was built up using principal components after adequately transforming the initial variables. A covariance model with the variable time as covariate was fitted, using GLIM, to see how this index can be used to distinguish between sites. Finally, robust procedures were applied in order to obtain more robust fits.
A non‐linear model of an open flow adsorption process
Authors: Argyelan J. , Nassar R.
Published: February 2007

A probabilistic model is developed that describes the dynamics of adsorption in open flow reactors in the case of non‐linear adsorption kinetics. The model accounts for the movement of solute molecules in the liquid phase, for the exchange of solute molecules between the liquid and outer layer (or compartment) of the solid phase and for movement of solute molecules between the outer and inner layers of the solid phase. From this model, one can predict the concentration of solute molecules in the exit stream of the reactor (breakthrough curve) over time. The model was applied to breakthrough curve data for trichloroethylene adsorption from water onto activated carbon. Model prediction was in good agreement with experimental data.
An application of locally weighted regression to airborne mercury deposition around an incinerator site
Authors: Opsomer Jean‐Didier , Agras Jean , Carpi Anthony , Rodrigues Geraldo
Published: February 2007

In this paper the deposition of mercury around an incinerator site is modelled using a non‐parametric technique, locally weighted least squares regression. We begin by summarizing current theory on how multivariate locally weighted linear regression can be used to generate a regression surface and to construct approximate F‐tests. We detail a simple implementation of the method that does not involve an adaptive bandwidth. This method is then applied to data on mercury accumulation in moss samples around an incinerator site, a situation where parametric modelling is not appropriate because of the small sample size and the presence of many potential covariates. The predicted regression surfaces are displayed using different bandwidth choices and suggest that the incinerator indeed affects the spatial distribution of mercury in the immediate vicinity of the incinerator. Approximate F‐tests indicate that this effect is statistically significant at the 10 per cent level only after the moss samples have been oven‐dried. A potential explanation for this finding based on the relative volatility of different mercury species is discussed.
Aluminium and the risk for alzheimer's disease
Authors: McLachlan D. R. C.
Published: February 2007

The strength of the evidence implicating aluminium as an important factor in the dementia of Alzheimer's disease (AD) is reviewed. We submit that the weight of the epidemiological and biological arguments is considerable. While a complete understanding has not been achieved, we recommend lowering aluminium exposure in municipal drinking water to below 50 μg/l in at least the province of Ontario. The Ministry of Energy and the Environment of Ontario maintains a drinking water surveillance programme which has provided a database for more than 10 years. This database has permitted assessment of the relative risk for AD using four independent measures of disease prevalence: 1. weighted residential history as a measure of exposure in autopsy‐verified AD cases and controls; 2. first admission hospital discharge diagnoses of AD and controls; 3. death certificate rates for AD and presenile dementia; 4. impairments in cognitive function in elderly males. Taken together, many of the criticisms applied to epidemiological studies conducted elsewhere and reaching similar conclusions have been met. A vast experimental database on aluminium neurotoxicity, rapid advances in the understanding of the molecular basis of AD, and comparison studies between human brains exposed to chronic low dose aluminium exposure secondary to renal failure and AD, lend strong biological support to the conclusions reached by the epidemiological studies. The factors initiating AD, how aluminium gains access to the brain in AD, and the relative contributions of food, pharmaceuticals and skin absorption, remain unknown. While a full understanding is not in hand, the devastating nature of the disease, the lack of an effective treatment or prevention and the high cost to the health care system, together with the human costs, weighed against the relative cost of moderately reducing drinking water aluminium concentration to reduce exposure indicate that action is both reasonable and timely.
Environmental tobacco smoke and lung cancer: Uncertainties in the population estimates but not in the causal association — a rejoinder to gross
Authors: Bayard Steven , Jinot Jennifer , Flatman George
Published: February 2007

This article is a rejoinder to the article by Gross in this issue, in which he claims that ‘any range [of estimates of lung cancer deaths attributable to environmental tobacco smoke (ETS)] 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 U.S. Environmental Protection Agency's (EPA) conclusion that ETS is a human lung carcinogen was based on the total weight of evidence, not just the 11 U.S. epidemiology studies of ETS and lung cancer that Gross discusses with respect to the population risk estimates. This conclusion was unanimously endorsed by the Agency's independent Scientific Advisory Board and is in concurrence with the conclusions of other organizations.

As for the population risk estimates, the EPA report acknowledges uncertainties in these estimates. However, we maintain that the estimate of 3000 lung cancer deaths per year in U.S. non‐smokers is a reasonable point estimate. Furthermore, we have relatively high confidence in this estimate compared to cancer risk estimates for other environmental pollutants, because it is based on human data from actual environmental exposure levels.
A new model pdf for contaminants dispersing in the atmosphere
Authors: Lewis D. M. , Chatwin P. C.
Published: February 2007

This paper illustrates the modelling of the probability density function for the concentration of a scalar dispersing in the atmosphere, using a simple modification of a two state distribution relevant to the hypothetical case of no molecular diffusion. The low concentration values are modelled by means of an exponential distribution, and the high concentration tails by a generalized Pareto distribution. The fits are generally better than those obtained using the beta distribution considered in earlier work. The new model links well with the α‐β theory for concentration moments in turbulent flows, discussed in other papers of this special issue ofEnvironmetrics.
A prognosis for the sudden release of contaminant in an environmental flow
Authors: Sullivan P. J. , Ye H.
Published: February 2007

A diffusing contaminant cloud is characterized by its location, size and state. The state of contaminant concentration reduction is the main concern in this paper and is represented by the expected‐mass‐fraction function. A bi‐Gaussian probability density function for concentration is developed and shown to describe measured probability density functions throughout the bulk of a variety of steady flows with continuous contaminant sources. The bi‐Gaussian density function is shown to be directly related to the α‐β prescription of moments and to enable the approximate prediction of the expected‐mass‐fraction function. A puff of contaminant released in the neutral atmospheric boundary layer is used as an illustrative example.
An outline of ecometric analysis to establish load diagrams for nutrients/eutrophication
Authors: Håkanson Lars , Wallin Mats
Published: February 2007

An outline of some central methodological steps in an ecometric analysis to develop load diagrams is given. This is done within the framework of an Expert system for environmental consequence analysis for natural aquatic ecosystems. Examples focus on nutrient emissions/eutrophication in coastal areas. The analysis is based on a number of fundamental concepts (effect, dose, sensitivity, area and time compatibility, ecometric analysis, load diagrams, etc.). The paper addresses questions concerning the basic set‐up of the Expert system, how to establish representative empirical data for entire coastal areas for various types of substances, e.g., nutrients, and parameters expressing eutrophication (e.g., Secchi depth, chlorophyll) and internal correlations among dose and sensitivity parameters. Limitations and advantages with the ecometric approach are stressed.
Time series analysis of the secondary clarifier
Authors: Ossenbruggen Paul J. , Hill Robert D. , Gaudard Marie
Published: February 2007

Full scale tests were performed to determine the effects of transient and return flows on the clarification process of activated sludge treatment. An ARIMA‐intervention model and a feedback‐feedforward control scheme for return flow was developed. Computer simulation runs were used to test the effectiveness of the control algorithm. The paper describes and discusses the model identification, the controller development and the controller's potential in application.
Models and their effect on regulation processes
Authors: Phatarfod R. M.
Published: February 2007

In many problems of regulation of water quantity and quality, a process of fundamental importance is that of cumulative sums — weighted or otherwise — of random variables forming a stochastic process. It is commonly believed that in such situations, the structure of the stochastic process is not important as long as the most important parameters remain the same. This means, for example, for a Markov process, with the same stationary distribution and the same serial correlation coefficient, the behaviour of the cumulative sums would be nearly the same. In this paper we show, by analytical methods and by simulation that this belief is erroneous, and that the structure of the input model has a significant effect, and that this effect increases with the serial correlation coefficient.
Statistics and environmental regulations
Authors: Flora Jairus D.
Published: February 2007

Statistics has historically played a role in studying the environment. Statistics has been used in determining the presence and amount of pollution of several types as well as studying the spread and health effects of pollution. More recently the role of statistics in environmental regulation has been explicitly recognized with new regulations requiring statistical approaches to study design, data collection and analysis, and monitoring programs of various types. Two disparate approaches to statistics in regulations have been taken: performance based regulations and method based regulations. Examples of each are discussed, together with the advantages and disadvantages of each approach. The interactions among statisticians, regulators, industry, and communities involved in environmental regulations are discussed.
Trend analysis methodology for water quality time series
Authors: McLeod A. Ian , Hipel Keith W. , Bodo Byron A.
Published: February 2007

A general trend analysis methodology is developed for detecting and modelling trends in water quality time series measured in rivers and streams. The procedure is specifically designed for use with typically ill‐behaved river quality series characterized by problematic features such as non‐normal positively skewed populations, irregularly spaced instantaneous observations, seasonal periodicities, and dependence among water quality variables and riverflows. In order to analyze these “messy” environmental data in a systematic and rigorous fashion, the overall trend analysis approach is divided into the two main categories of graphical studies and trend tests. Within these two main steps, specific graphical, parametric and nonparametric statistical techniques are utilized. Graphical methods used in the procedure include time series plots, robust regression smooths, as well as box and whisker graphs. Nonparametric techniques include the Mann‐Kendall and Kruskal‐Wallis tests. Additionally, a test based on Spearman's partial rank correlation is introduced as a means for eliminating seasonal effects when testing for the presence of a trend. The efficacy of the trend analysis methodology is explained and demonstrated by applying it to water quality time series observed in the Saugeen and Grand Rivers of Southwestern Ontario, Canada.
Evaluating the impacts of a hydro‐electric development in northern Manitoba, Canada
Authors: Shay C. T. , Shay J. M. , Johnston B.
Published: February 2007

In an attempt to make optimal use of the seasonal water flow of the Churchill River for hydroelectric generation, a storage basin was created utilizing Southern Indian Lake (SIL). A dam raised the lake level by 3 m. The water was diverted primarily to the Nelson River system and its hydro stations. The increased water level changed the character of SIL. Flooding inundated the forest around the lake and the biomass that was flooded began to decompose.

This study has two parts. First, we develop estimates of the flooded biomass and outline some consequences of the flooding. About 4,500 metric tonnes of biomass entered the water of one small bay of SIL. Secondly, we review the project and emphasize the need for comprehensive planning involving environmental and social scientists.
On the propagation of fuzziness of data
Authors: Schnatter Sylvia
Published: February 2007

The object of this paper is to discuss how fuzziness of data is propagated when statistical inference for samples of non‐precise data is carried out.

The method of propagation of fuzziness as introduced by Schnatter (1989) is reviewed. This method may be applied to any statistical method which leads to a result that may be expressed as a function f(x1,…,xn) of the data x1,…,xn. It is outlined that practical application of this method is equal to determining the images of a family of compact subsets of the sample space under the function f(·).

An illustrative example from environmetrics is discussed. The general approach is used to formulate a fuzzy sample mean and a fuzzy valued empirical distribution function.
Application of negative binomial regression models to the analysis of quantal bioassays data
Authors: Maul A. , El‐Shaarawi A. H. , Ferard J. F.
Published: February 2007

The problem of developing an approach for modelling the response of an organism to chronic toxicity is discussed in this paper and illustrated by studying the toxic effect of NaBr on the reproduction process of a population of Daphnia magna. A general model is given which includes both the negative binomial and poisson distributions as special cases depending on the values of a single parameter. The steps involved in estimating the parameters of the model and testing the goodness‐of‐fit are presented. In particular the iterative solution of the estimating equations are described in detail along with the problem of setting confidence limits for model parameters. This approach is useful in the analysis of quantal bioassay data.
Inverse modelling of environmental pollution: The role of statistics
Authors: Dovì V. G.
Published: February 2007

Modelling is currently used in problems connected with the assessment of environmental impact. This class of problems is generally well defined, in that all the characteristics (such as location, strength, etc.) of potential sources of pollution are known. On the other hand, receptor analysis uses the experimental information available in the environment (such as air or water quality) to identify polluting sources. This is why they are generally called inverse problems.

The reasons for the negligible amount of research effort in the application of inverse modelling is due to the ill‐posed character (i.e. lack of continuity) of the operator that describes the problem. Nevertheless, large strides have been made in the so‐called regularization of inverse operators, which makes use of additional available information.

The aim of this paper is to explore how the statistical information employed in receptor analysis can be used for regularization purposes in the general inverse modelling of environmental problems.
B‐spline approximation for the baseline hazard function
Authors: Angelos James , Lee Carl M.‐S. , Singh Karan P.
Published: February 2007

Etezadi‐Amoli and Ciampi (Biometrics 1987) introduced a method to approximate the baseline hazard and to estimate the regression coefficients for covariates simultaneously for the extended hazard regression (EHR) model using a quadratic spline approach. In this paper, an estimate of the baseline hazard function by B‐spline approximation using a minimax criterion is proposed. The nonlinear problem is approximated by a linear programming problem with only linear constraints. The nice features of this approach are: (i) the minimax criterion provides a robust approximation to the hazard function, and (ii) the linearized problem is numerically simple and fast.
Relative performance of two dust samplers: An application of robust regression
Authors: Sutradhar B. C. , Azam M. N. , Moore E.
Published: February 2007

The respiratory health condition of the workers in mines is affected by concentration of dust mainly deposited due to production activities. Two standard dust sampler instruments (NY and ME) were used to measure the dust concentration in two mining complexes in Labrador, Canada. The dust absorption capacity of these samplers is assumed to be influenced by temperature and humidity of the experimental environment. This paper examines the relative performance of the two dust samplers NY and ME taking the covariates temperature and humidity into account. This is achieved through a robust regression analysis by regressing the ratio of dust concentrations measured by NY and ME on temperature and humidity. Also robust regression results are compared with classical multiple regression based on the power transformation.
Inference about covariances under missing values
Authors: Provost Serge B.
Published: February 2007

The likelihood ratio criterion for testing the mutual independence ofqsubvectors of anl‐dimentional normal vector on the basis of a sample of sizeNonlcomponents and of an incomplete sample of sizeMonrcomponents (r < l). This is equivalent to testing the hypothesis that each variable in one subvector is uncorrelated with each variable in the other subvectors. This asymptotic distribution of the test statistic is given.
Wastewater concentration by seeded reverse osmosis: A field demonstration in the electric power industry
Authors: Hess Mary Chionis , Jones George , Micheletti Wayne , Tomlinson Joe
Published: February 2007

Waste minimization is a key objective of power plant water/wastewater management. Even though membrane processes, such as reverse osmosis, have been used for makeup water treatment, their applications to waste minimization have been very limited. Although the field test results for a seeded reverse osmosis (SRO) system were not absolutely conclusive, the SRO system offers some unique features which may enable the utility industry to realize the advantages of membrane separation processes for wastewater concentration without extensive pretreatment and the associated costs.
Municipal solid waste composition and the behavior of metals in incinerator ashes
Authors: Clapp T. L. , Magee J. F. , Ahlert R. C. , Kosson D. S.
Published: February 2007

Disposal of solid and hazardous wastes has become a concern in recent years. Incineration is a promising option for both, however, there are questions of public health effects and environmental acceptability of incinerator outputs. Ideally, operating conditions could be controlled to limit toxicity of residuals; to develop process models and feed‐back algorithms requires knowledge of the causal relationships between input and output to quantify induced responses.

The composition of municipal solid wastes (MSW) from residential service areas was categorized and residuals from MSW incineration were examined for metal content and leachability. Sample size, sampling methodology, segregation by category and homogeneity of service area were determined to be dominant factors influencing the composition of MSW. There were notable differences in metal content of the fly and bottom ash residuals. Lead and zinc were the dominant trace metals in both ash residuals. Concentrations of cadmium and lead leached from the flyash were found to exceed EP limits. Lead and cadmium of both bottom ash and flyash fail proposed TCLP extraction limits by even larger margins. Permanent elimination of high‐temperature process ashes, classified as hazardous, must be demonstrated.
Nanofiltration extends the range of membrane filtration
Authors: Eriksson Peter
Published: February 2007

Nanofiltration is a pressure driven membrane process between reverse osmosis and ultrafiltration. The rejection is low for salts with monovalent anion and nonionized organics with molecular weight below 150 while high for salts with di‐ and multivalent anions and organics with molecular weight above 300. Examples of applications are removal of color and TOC from Florida surface water, removal of hardness, radium, and sulfate from well water, removal of sulfate from seawater and simultaneous removal of sodium chloride and concentration of organics with molecular weight 300–1000 in the food and pharmaceutical industries. The investment cost for a nanofiltration plant is about the same as for a brackish water reverse osmosis plant, but the energy savings can be considerable by using nanofiltration instead of reverse osmosis.
Low NOx, high efficiency multistaged burner: Gaseous fuel results
Authors: Srivastava Ravi K. , Mulholland James A.
Published: February 2007

A multistaged combustion burner design is being evaluated on a 0.6 MW package boiler simulator for in‐furnace NOx control and high combustion efficiency. A low NOx precombustion chamber burner has been reduced in size by approximately a factor of two (from a 600 ms first‐stage residence time to 250 ms), and, for additional NOx control, coupled with [1] air staging, resulting in a three‐stage configuration, and [2] natural gas fuel staging, yielding up to four stoichiometric zones. Natural gas, doped with ammonia to yield a 5.8 percent fuel nitrogen content, was used to simulate a high nitrogen content fuel/waste mixture. In low NOx burner baseline tests, without advanced staging, a 315 ppm NO emission (measured dry, corrected to zero percent O2) was measured, compared with an emission of 1000 ppm measured using a conventional, unstaged burner. Both of the multistaged combustion modifications for additional NOx control reduced NO emissions by an additional 50 percent, to 160 ppm meeting the program goal. However, air staging application resulted in the entire front end of the boiler being fuel‐rich, whereas fuel staging, or reburning, in the boiler required only a small fuel‐rich flame core in the boiler. Further, no boiler penetrations were necessary with reburning modification, as staged fuel and air were injected through the boiler front wall; access for burnout air injection deep into the boiler was necessary for the air staging modification. Thus, the four‐stage configuration, combining the precombustion chamber burner and reburning, appears to be the most promising approach for minimizing NO emissions and maximizing primary fuel/waste destruction.
Identification and quantification of volatile organic species during microbial treatment of leachate
Authors: Sikkema Stephen , Dienemann Erik , Ahlert Robert , Kosson David
Published: February 2007

Sequential anaerobic/aerobic microbial populations, in a packed‐bed configuration, were employed to biodegrade leachate from a high priority Superfund site. Leachate characteristics included up to 100 ppm (as carbon) volatile organic priority pollutants. Identification and quantification of these pollutants at key steps in the biodegradation process is important. A method employing purge and trap concentration followed by gas chromatographic separation was developed for accurate identification and quantification of the volatile compounds of interest. Results obtained from application of this method to the leachate treatment process indicated that 84 to 99% of the specific volatile priority pollutants were biodegraded, under anaerobic conditions, during steady‐state operation.
The simultaneous removal of oil and heavy metals from industrial wastewater by joint precipitation and air flotation
Authors: Gopalratnam Venbakm C. , Bennett Gary F. , Peters Robert W.
Published: February 2007

A joint precipitation and air flotation system was used to simultaneously remove oil and heavy metals from an industrial wastewater. The wastewaters were subjected to hydroxide treatment and chemical collectors simultaneously. The flotation tests were run for 4 min. For the particular wastewaters studied, the optimal pH and air injection rate was 9.18 and 12,150 cm3/min, respectively. Three different chemical collectors were investigated (WOF‐67, Nalco‐7182, and Jayfloc‐806*); the optimal collector dosage was typically in the range of 2–5 mg/L (depending on the particular chemical collector and heavy metal of concern). Removals of the heavy metals and oil typically exceeded 85%; oil removals are great as 96.2% were achieved. Removal of the heavy metals and oil probably occurred through a coprecipitation‐adsorption mechanism. Removals of the various heavy metals compared favorably between the individual removal and simultaneous removal (of heavy metals and oil) studies. By appropriate choice of the chemical collector, its dosage, pH and air injection rate, the selectivity for individual metal species can be affected.
Lamella settlers: Material balances and clarification rates
Authors: Maimoni Arturo
Published: February 2007

We show that material balances and clarification rates of a lamella settler can be obtained from the particle size distribution and density of the solid, the density and viscosity of the liquid, the desired concentration of solids in the overhead product, and the concentration of solids in the feed and underflow, using an algorithm based on a simple geometric model. The method was validated using concentrated suspensions (up to 20 vol% solids) of four different feed‐particle size distributions of hydrargillite (aluminum hydroxide) in water. Most of the data were obtained in a 60‐cm‐long settler with 1‐cm plate separation inclined at 60° to the horizontal in “open bottom” and “normal” configurations. The algorithm is not applicable to tube settlers, whose hydrodynamics are more complex.
Aquifer restoration: Chlorinated organics removal considerations in proven vs innovative technologies
Authors: Dworkin Daniel , Cawley Mark W.
Published: February 2007

The arguments over the use of proven vs. innovative technologies have gone on since the inception of the scientific and engineering communities. Currently, the discussions and interactions regarding “applicable” technology and when and where to use it focus on groundwater contamination. The need for removal of chlorinated organic compounds looms large as one of many groundwater treatment problems. Widely accepted technology keys on carbon as the solution; however, carbon is not without problems. Alternative innovative approaches include volatilization and biologic degradation. The alternatives have applicability and also certain limitations.
Treatment of a water‐reactive powder
Authors: Fochtman E. H. , Swanstrom C. , Cashen T.
Published: February 2007

The treatment of water‐reactive solid waste chemicals which generate corrosive products poses unique problems of feeding and reactor design. These problems have been addressed on a bench‐scale and the design of a unit suitable for hazardous waste has been developed. The water‐reactive material used was powdered titanium trichloride which was reacted with water (and oxygen) to give titanium dioxide and hydrochloric acid. The acid was neutralized by an alkaline scrubbing media.
Hazardous waste minimization audits using a two‐tiered approach
Authors: Resch Michael E.
Published: February 2007

The auditing procedures presented here can be used either by personnel contracted to perform minimization audits at client facilities or by in‐plant personnel performing minimization “self‐audits”.
Waste reduction: Program, practice and product in chemical manufacturing
Authors: Delcambre Ryan
Published: February 2007

Waste Reduction has been a daily pursuit of manufacturing operations for many years. During the 1970's, as feedstocks and energy costs escalated, a renewed emphasis was placed on yield improvement and energy conservation. These improvements, in many cases, reduced the volume of unwanted byproducts that had to be managed as waste and increased the overall productivity of the manufacturing process.
Use of fly ash as a waste minimization strategy
Authors: Wentz C. A. , Moretti C. J. , Henke K. R. , Manz O. E. , Wiken K. U.
Published: February 2007

Cost‐effective liner materials for waste disposal that would meet state regulatory requirements for liner permeability while reusing coal combustion fly ash, reducing ash disposal costs were developed. Liner development criteria included a permeability of less than 10−7 cm/s and a durability comparable to that of conventional clay liners. Fly ash samples from six utility companies located in five states were used. These samples were representative of the large quantities of fly ash available from coal‐fired power plants. When mixed with 3–9.5% by weight portland cement and/or lime, each of the samples yielded liners with permeabilities significantly less than 10−7 cm/s and compression strengths generally exceeding 400 psig. Liner construction costs ranged from $0.05 to $0.44 ft [3], with the costs depending on the quantities of fly ash and additives used, formulation mixing method, and placement and compaction methods for the lifts. Studies of leachate from each fly ash found that none of them would be hazardous under current regulatory guidelines.
Source reduction technical assistance: A pilot project and its implications for the chemical industry
Authors: Dane Lee
Published: February 2007

As part of its developing source reduction program, the Massachusetts Department of Environmental Management (DEM) has conducted a technical assistance project with precious metals platers in the southeast region of the Commonwealth. During this project, DEM identified a number of raw material substitutions and source reduction technologies that significantly reduce both costs and volumes of hazardous waste generated. DEM suggests ways in which the chemical industry might respond to market change, and details ways in which non‐regulatory agencies can foster source reduction and encourage expanded markets for source reduction chemistries and technologies.
The effect of acid rain legislation on the economics of CO2recovery from power plants
Authors: Cobb Thomas B. , Streets David G. , Veselka Thomas D. , Wolsky Alan M.
Published: February 2007

Proposed acid rain legislation and the long‐term need to enhance domestic oil production could combine to make economic the recovery and use of SO2/CO2mixtures that are now vented to the atmosphere from the smokestacks of fossil‐fired combustors.
Removal of humic acid and toxic organic compounds by iron precipitation
Authors: Ying Wei‐Chi , Duffy James J. , Tucker Michael E.
Published: February 2007

Removal of humic acid is necessary to ensure efficient removal of many toxic organic compounds such as PCBs and chlorinated pesticides. Precipitation either as ferrous or ferric hydroxide is far more effective for removing humic acid than activated carbon adsorption and lime‐soda softening processes. Many recalcitrant compounds, such as HET acid, are also removed by chemisorption on newly‐formed ferric hydroxide flocs. An integrated waste treatment process consisting of iron precipitation, biodegradation, and carbon adsorption was developed for complete and efficient treatment of chemical waste landfill leachates and other highly contaminated industrial wastewaters.
Volatile organic compounds in indoor air: Types, sources, and characteristics
Authors: Gammage R. B. , Matthews T. G.
Published: February 2007

Examples are given of occupant activities and consumer and construction products inside residences that cause transient and persistent emissions of volatile organic compounds (VOC). Transient emissions arise from window cleaning, carpet laying, smoking, and automobile operations. Persistent VOC emitters include gasoline, mothballs, and pressed‐wood products containing urea formaldehyde resins. Simple screening methods are given for making indoor measurements of VOC. Detailed laboratory and research house studies of formaldehyde emissions decay from pressed‐wood building products are described.
Biological treatment of leachate from a superfund site
Authors: Opatken Edward J. , Howard Hinton K. , Bond James J.
Published: February 2007

Studies were made on treating a leachate from New Lyme, Ohio. The leachate was transported to Cincinnati, where a pilot‐sized rotating biological contactor (RBC) was used for a treatment evaluation. Biomass was developed on the RBC discs with primary effluent from the City of Cincinnati's Mill Creek Sewage Treatment Facility. Experiments were then conducted to determine the effectiveness of treating a hazardous waste leachate and to provide information on: the rate of organics removal; the final effluent quality; the fate of priority pollutants and specific organic compounds; and the loss of volatiles via stripping in the RBC. The results of these experiments and the applicability of an RBC to treat a hazardous waste leachate from a Superfund site are reported.
Modeling and analysis of moving‐bed hot‐gas desulfurization processes
Authors: Ayala Raul E. , Kim Bang Mo
Published: February 2007

Removal of sulfur compounds from hot coal gas is a necessary step during power generation operations. Zinc ferrite has been identified as a promising absorbent material. A mathematical model describing the kinetics of zinc ferrite during absorption and regeneration as it applies to a steady‐state moving‐bed concept, where the solids are continuously transferred between absorber and regenerator vessels has been developed. Model predictions, based on experimental data, are presented for various flow configurations and operating conditions, including multistage operation of regeneration, where the effect of diffusion mechanisms, temperature, gas concentrations, and flow rates on conversion are presented.
Metal ion scavenging from water with fine mesh ion exchangers and microporous membranes
Authors: Grinstead Robert R. , Paalman H. Hunter
Published: February 2007

The productivity of ion exchange processes is usually limited by the diffusional process. The use of very fine mesh resins (down to 10–25 microns diameter) in very thin (ca 3–9 mm) beds supported on a microfiltration membrane of three micron pore diameter is described. These systems were used to process a simulated wastewater containing 4000 ppm of NaCl, plus some calcium and magnesium chlorides, as well as 0.2 ppm each of the metal ions Cu, Ni, Pb, Zn, and Cr (III). Regeneration with dilute HCl produced a concentrate of 1/1000 the volume of the feedwater treated.
Evaluation of alternative processes for final treatment of hazardous waste effluents
Authors: Meardon John A. , Lyandres Sol , Rees John T. , Shealy Stuart
Published: February 2007

Five process unit operations were evaluated for effectiveness in treating aqueous effluent from a hazardous waste treatment facility. The aqueous effluent contained residual amounts of various organics and heavy metals. The objective of the pilot test program was to produce an aqueous product which could meet requirements for discharge to a POTW, or directly to the environment, and a solid product which could be disposed of in a Class I landfill. Processes evaluated included one primary, evaporative crystallization, two secondary, activated sludge bio‐treatment and reverse osmosis, and two tertiary, carbon adsorption and ultraviolet peroxidation. Test results from these process operations identified several processing configurations whereby the final treated product could meet discharge criteria. Performance results of each process unit operation are summarized and discussed.
Waste minimization opportunities at an electric arc furnace steel plant producing specialty steels
Authors: Drabkin Marvin , Rissmann Edwin
Published: February 2007

Waste reduction assessments have been carried out in the Armco, Inc. Butler, Pennsylvania electric arc furnace (EAF) specialty steelmaking complex. These assessments were intended to develop waste reduction options for two hazardous waste streams at this facility: heavy metals waste and corrosive waste. Waste reduction options considered were in one of two categories: source reduction or recycling (in the same order of preference). Treatment was considered only if waste reduction options were unavailable.
Biodenitrification of uranium refinery wastewaters
Authors: Walker J. F. , Helfrich M. V. , Donaldson T. L.
Published: February 2007

Design verification studies and process development work were conducted at Oak Ridge National Laboratory in support of the new fluidized‐bed biodenitrification system under construction at the Feed Materials Production Center (FMPC) in Fernald, Ohio. Two bioreactors in series, each 6‐m tall, and one 12‐m‐tall bioreactor were operated for approximately 9 months using synthetic and actual wastewaters from the FMPC. The results indicate that satisfactory reaction rates can be achieved and maintained; however, some degree of water softening, pH adjustment within the bioreactors, and temperature control may be necessary.
Treatment of hazardous substances in wastewater treatment plants
Authors: Stenstrom Michael K. , Cardinal Lynne , Libra Judy
Published: February 2007

For many types of hazardous wastes, particularly those contained in high volume, low concentration wastewaters, biological treatment in existing facilities, perhaps in selected publicly owned treatment works (POTWs), may be a better alternative. The motivation for using existing biological facilities to treat hazardous wastes is very high since there is insufficient hazardous waste treatment capacity. This problem will become exacerbated in the future unless the current hazardous waste facility problems are resolved.
Biotreatment of dilute contaminated ground water using an immobilized microbe packed bed reactor
Authors: Portier Ralph J. , Nelson John A. , Christianson John C. , Wilkerson J. Mark , Bost Richard C. , Flynn Brian P.
Published: February 2007

A biological treatment process employing immobilized microbial populations was field tested on contaminated ground water having dilute concentrations of volatile organics and organic pesticides. The process, consisting of two packed bed reactors in series containing specific adapted microbial strains immobilized on a porous diatomaceous earth support, was operated in a plug flow configuration over a 90‐day period at a flow rate of 80 gallons per day (gpd). Process viability of this multiple microbe/multiple toxicant treatment approach was determined based upon comparisons to carbon adsorption technology.
Industrial sludge waste incineration
Authors: Brunner Calvin R.
Published: February 2007

A fluidized bed incinerator was installed to handle sludge disposal. Construction and the permit process is discussed.
Chemical demilitarization: Disposing of the most hazardous wastes
Authors: Rife R. , Thomas T. W. , Norberg D. W. , Fournier R. L. , Rinker F. G. , Bonomo M. S.
Published: February 2007

This country's aging stockpile of chemical warfare munitions require safe and economical disposal. These munitions present a unique challenge for demilitarization, since handling of both explosives and toxic material is required. The first full‐scale munitions disposal facility is presently undergoing testing and systemization on Johnston Island. The technology developed for incorporation into the Johnston Atoll Chemical Agent Disposal System maximizes the use of automated equipment, provides the containment necessary to protect the worker and environment, and thermally destroys both the toxic fill and explosives from the munitions.
Destroying hazardous waste on site—avoiding incineration
Authors: Galloway Terry R.
Published: February 2007

Conventional rotary kiln incineration technology is contrasted with the new Thermolytica steam gasification technology from the outlook of the small generator. Technical performance, on‐site compatibility, environmental safety, and economics, are discussed from, the viewpoint of the small generator together.
Evaluation of membrane processes for the reduction of trace organic contaminants
Authors: Lyandres Sol , Meardon John , Rees John
Published: February 2007

Reverse osmosis (RO) was experimentally tested on liquid condensates produced from a pilot evaporative crystallizer. The condensates contained residual light organic compounds. The original sources of the condensate feeds were two solar evaporation ponds that received treated liquid effluents from a hazardous waste treatment and disposal facility. The objective of the tests was to reduce total organics concentrations (TOC) to levels acceptable for discharge into the local POTW or surface waters.
Myers dump case history: Innovative utilization of air stripper‐activated carbon technologies
Authors: Binkley Jeffrey S. , Matz Sally , Myers Kenneth L. , Theisen Kenneth
Published: February 2007

The treatment of residential well water contaminated with volatile organic compounds (VOCs) has typically included the use of granulated activated carbon (GAC) filters. The significant carbon replacement costs associated with filtration has prompted research into more cost effective alternatives. Another alternative for treatment of ground water contaminated with VOCs is air stripping. This process does not require extensive maintenance costs but it generally cannot achieve the required removal levels for small scale applications. The combination of these two technologies can result in achieving optimum removal levels while reducing carbon replacement costs. The case history described in this paper outlines the removal effectiveness monitoring program of a remediation technology utilizing air strippers in conjunction with GAC filters. Specific topics discussed in this paper include: site background, health effects, system design and installation, removal effectiveness monitoring, quality assurance program, and effectiveness and efficiency of the technology.
Reduction of sulfur dioxide by syngas to elemental sulfur over iron‐based mixed oxide supported catalyst
Authors: Jin Yun , Yu Qiquan , Chang Shih‐Ger
Published: February 2007

An iron‐based supported catalyst has been developed for the reduction of SO2 by synthesis gas to obtain more than 97% yield of elemental sulfur with a single stage reactor for 340–480°C (30–40 mesh particles), 440–580°C (d · 3 mm × h · 5 mm granules). Parametric studies on the performance of the catalyst have been conducted. The parameters studied include temperature, space velocity, molar ratio of H2 to CO, molar ratio of syngas to SO2 in the feed, and particle size of the catalyst. A lifetime test has been successfully performed. The mass balance of sulfur and carbon has been demonstrated.
Performance update: Low pressure wet air oxidation unit at grangemouth, Scotland
Authors: Matthews Roger
Published: February 2007

In response to a requirement to provide a low‐capital, low operating cost solution for the treatment of steam cracker spent caustic, BP Chemicals Ltd. (BPCL) and Stone and Webster Engineering Ltd. (SWEL) have jointly developed a Low Pressure Wet Air Oxidation Process.

The first of these units has been in operation at the BPCL Grangemouth, Scotland facility for the last three years. In that time, it has demonstrated totally effective sulfide removal, surpassing design targets, and producing a neutralized effluent well within the allowable discharge consents for the site.

The Grangemouth unit is designed to treat the spent caustic effluent from two crackers with a combined capacity of 600 KTA (currently being expanded to 700 KTA) from both liquid and gas feedstocks. A significant feature of the installation has been the extremely high level of reliability and availability, ensuring trouble‐free operation and full compliance with effluent consent levels mandated by the regulatory authorities. At the same time, the unit has demonstrated very low operating and maintenance costs.

The design basis and initial commercial experience was presented at the AIChE Spring National Meeting in April 1994 [1]. This paper concentrates on the operational history of the Grangemouth unit, highlighting the process developments and improvements that have been made in the last three years.
Why valves leak: A search for the cause of fugitive emissions
Authors: Bello C. E. , Siegell J. H.
Published: February 2007

To better focus fugitive emission control efforts, a number, of valves that were removed from service due to poor emissions control performance were inspected for signs of damage to the stem sealing system. Corrosion and pitting of the stem were found to be the highest identifiable causes of high valve fugitive emissions. Most valves, however, had no identifiable damage and poor emissions control performance in these cases is believed to be due to poor packing materials or poor packing installation procedures.