Air and Waste

In dry and spray-dry flue gas desulfurization, a fabric filter significantly improves the removal of SO2, This report describes the reactivity of a deposited absorbent particle layer with SO2 by three reactivity parameters in a semi-empirical model. These parameters for four different lime hydrates were obtained from fixed-bed reactor experiments by regression analysis. The SO2 removal in a fabric filter was then theoretically predicted. Results obtained with this method are in good agreement with pilot scale findings reported in the recent literature. The reactivity measurement followed by simulation procedure described here can be used to predict the influence of design and operating variables on the SO2 removal in a fabric filter.

Jarl R. Ahlbeck

Stefan Rönnblad

Air & Waste

Removal of Sulfur Dioxide in a Fabric Filter

This paper describes an instrument developed for the semi-continuous measurement of aerosol mass and its categorization into three classes. These classes have been chosen to evaluate the health hazards of the inhalable particles. The instrument performs sampling through three probes, each providing different cut-points (~15, ~4 and ~2 µm) and collecting airborne particles on circular membrane filters. The increase in weight is measured with the beta-rays attenuation method.

Giuseppe Schirripa Spagnolo

Domenica Paoletti

Automatic System for Three Fractions Sampling of Aerosol Particles in Outdoor Environments

户外环境气溶胶颗粒三分样自动采样系统

The U.S. Environmental Protection Agency (EPA), in cooperation with the Toronto Harbour Commissioners (THC), conducted a Superfund Innovative Technology Evaluation (SITE) demonstration of the THC Soil Recycle Treatment Train. The treatment train consists of three technologies operated in sequence: a soil wash process, a metals removal process, and a biological treatment process. The THC conducted an extensive demonstration of the treatment train at a 55 tons per day pilot plant in order to evaluate an approach for remediation of industrial/commercial sites that are situated in the Toronto Port Industrial District (PID). Three soils were processed during the THC demonstration. The EPA SITE demonstration project examined, in detail, soil processing from one of the sites being evaluated as part of the overall THC project. Contaminants included organic compounds and heavy metals. It has been estimated by THC that as much as 2,200,000 tons of soil from locations within the PID may require some form of treatment due to heavy metal and/or organic contamination that resulted from various industrial processing operations. The objective of the SITE demonstration was to evaluate the technical effectiveness of the process in relation to THC’s target criteria. Gravel and sand that met the THC target criteria for medium to fine soil suitable for industrial/commercial sites was produced. The fine soil from the biological treatment process did not meet the target level of 2.4 ppm for benzo(a)pyrene. However, there was a significant reduction in polynuclear aromatic hydrocarbon (PAH) compounds. The metals removal process achieved reductions of greater than seventy percent for copper, lead, nickel, and zinc.

Teri L. Richardson

Leo Ehrenreich

SITE Demonstration of the Toronto Harbour Commissioners Soil Recycling Project

多伦多港务局土壤再生项目现场示范

Elemental carbon (EC) particles have been found in the lungs of dolphins. The question arose as to whether these particles originated over land or water. This project determined the amount of EC particulate found in terrestrial air. Portions of paniculate filters and associated data collected during the period from January 1990 through December 1991 were provided by the Florida Department of Environmental Regulation. Using reflectance spectroscopy and laboratory-generated standards, atmospheric concentrations of EC and TSP were determined. This paper addresses the data from those counties which surround Tampa Bay. In the spring of 1992, a television news station reported that researchers at Mote Marine Institute had found black carbon particulates in the lungs of dolphins (reported as “...dolphins with Black Lung Disease..."). The dolphins were found in the Gulf of Mexico off the coast of Florida.1 In discussions with a principal investigator of the dolphin study, the question arose as to whether these particulates came from urban or marine sources. No comprehensive investigation of soot concentrations in the air over Florida had been made. This study reports the elemental carbon (EC) content of urban particulate matter in the Tampa Bay region, where the affected dolphins were discovered between 1988 and 1990 (Sarasota County). This is the first step toward answering whether urban concentrations of EC were sufficient to contribute measurably to the EC found in the marine environment. Future efforts will address marine concentrations and sources of EC. Elemental carbon, commonly termed “soot,” is a product of incomplete combustion. Common urban sources of EC in particulate matter include both mobile sources (diesel-powered buses, cars, and trucks) and point sources (incinerators, power plants and home heating units). The State of Florida operates environmental monitoring stations in selected municipalities around the state. At these stations, which were sited according to EPA requirements2, Total Suspended Particulate (TSP) samples were collected using the accepted methods.3 These samples were suitable for EC analysis. Samples collected in the Tampa Bay region in 199b and 1991 were analyzed for EC content using reflectance spectroscopy. EC concentrations were calculated in micrograms per cubic meter (μg/m3).

Jon Leonard

R. Del Delumyea

Elemental Carbon Concentration in the Air Around Tampa Bay, Florida, 1990-1991

佛罗里达州坦帕湾周边空气中的元素碳浓度，1990-1991年

The IAPCS model, developed by U.S. EPA’s Air and Energy Engineering Research Laboratory and made available to the public through the National Technical Information Service, can be used by utility companies, architectural and engineering companies, and regulatory agencies at all levels of government to evaluate commercially available technologies for control of SO2, NOx, and particulate matter emissions from coal-fired utility boilers with respect to performance and cost. The model is considered to be a useful tool to compare alternative control strategies to be used by utilities to comply with the requirements of the CAA, and to evaluate the sensitivity of control costs with respect to many of the significant variables affecting costs. To illustrate the use of the model for site-specific studies, the authors used the model to estimate control costs for SO2 and NOx control at Detroit Edison’s Monroe plant and two hypothetical plants under consideration and at three plants operated by New York State Electric and Gas Corporation. The economic and technical assumptions used to drive the model were those proposed by the utilities if cited, and if not cited, the model default values were used. The economic format and methodologies for costs cited in the Electric Power Research Institute’s Technical Assessment Guide are used in the IAPCS model. Depending on the specific conditions and assumptions for the cases evaluated, SO2 control costs ranged from $417 to $3,159 per ton of SO2 removed, and NOx control costs ranged from $461 to $3,537 per ton of NOx removed or reduced.

Norman Kaplan

Eric Soderberg

Deborah Pickett

James Meyers

IAPCS: A Computer Model that Evaluates Pollution Control Systems for Utility Boilers

IAPCS：一种评估公用锅炉污染控制系统性能的计算机模型

Exposure of plants to ozone (O3) causes injury and reduced growth. Describing the form and function of the O3 exposure in relation to plant response is important in the regulatory process. Research has shown that plants show greater response to O3 as concentration increases. The duration of the O3 exposure is also important in the ability of vegetation to maintain O3 repair mechanisms. The O3 entering the leaf is important in plant response, thus O3 fluxes are more important than ambient concentrations. However, at this time an air quality standard useful for the regulatory process should be based on ambient O3 exposures. The selection of O3 exposure descriptors should incorporate factors pertinent to plant response. Research suggests that exposure descriptors which give greater weight to peak concentrations, and those which account for cumulative exposure, show the closest relationship to plant response. Ozone exposure summaries using concentration averages do not adequately relate plant response with ambient exposures. Although the use of cumulative exposure indices may be preferable to seasonal means, it appears that the use of a single-parameter exposure index will not guarantee that the most important components of exposure have been captured. An appropriate alternative approach might use a combination of indices, such as a cumulative index and the number of hourly average concentrations above a threshold.

Robert C. Musselman

Patrick M. McCool

Allen S. Lefohn

Ozone Descriptors for an Air Quality Standard to Protect Vegetation

保护植被的空气质量标准中的臭氧描述符

Many state and federal agencies have prepared risk assessment guidelines, which describe methods for quantifying health risks associated with exposure to vapors and particulates emitted from point and area sources (e.g., California Air Pollution Control Officers Association [CAPCOA] under the Air Toxics "Hot Spots" Act [Assembly Bill 2588] and the U.S. Environmental Protection Agency [EPA] under the Clean Air Act). In general, these guidelines recommend or require the use of upper bound "point" estimates for numerous exposure parameters. This methodology yields a single risk estimate, which is intended not to underestimate the true risk and may significantly overstate it. This paper describes a risk assessment of a facility's airborne emissions using a probabilistic approach, which presents a range and distribution of risk estimates rather than a single point estimate. The health risks to residents living near a food processing facility, as estimated using techniques recommended by California AB2588, are compared to the results of a probabilistic analysis. Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were identified as the emitted chemicals of concern. The point estimate method recommended by CAPCOA resulted in estimates that were greater than the 99.99th percentile risk predicted by the probabilistic analysis. As shown in other assessments of persistent airborne chemicals, secondary or indirect exposure pathways (i.e., ingestion of beef, ingestion of cow's milk, and ingestion of mother's milk) rather than inhalation, were the greatest contributors to risk. In this analysis, the probability distributions for the cancer potency factor and ingestion of cow's milk had the largest impact on the results of the 33 exposure factors considered.

Teri L. Copeland

Ann M. Holbrow

Joanne M. Otani

Kevin T. Connor

Dennis J. Paustenbach

Use of Probabilistic Methods to Understand the Conservatism in California’s Approach to Assessing Health Risks Posed by Air Contaminants

使用概率方法理解加利福尼亚州评估空气污染物带来的健康风险中的保守性

As the time approaches for the U.S. Environmental Protection Agency (EPA) to evaluate whether risks from electric utility trace substance emissions are of concern, attention is focused on research to clarify the many issues surrounding this topic. Accordingly, more than 230 representatives of industry, government, international research and academic institutions, equipment manufacturers, and engineering service firms attended the Second International Conference on Managing Hazardous Air Pollutants, which was held in Washington, D.C., on July 13–15,1993. Sponsored by the Electric Power Research Institute (EPRI) in cooperation with the EPA, U.S. Department of Energy (DOE), PowerGen, Coal Research Division of the International Energy Agency, and Canadian Electrical Association, the conference featured more than 50 presentations that both asked and answered questions about utility emission sources, the atmospheric fate of emitted substances, health and environmental studies, risk assessment, and control technologies. The diversity of the audience produced a stimulating exchange of findings, interpretations, and assessments of remaining uncertainties. This exchange provided valuable direction for ongoing research activities worldwide.

Winston Chow

Leonard Levin

Michael Miller

Richard Myhre

Highlights of the Second International Conference on Managing Hazardous Air Pollutants

第二届国际危险空气污染物管理会议亮点

The kinetics of H2S oxidation in a biofilter were evaluated and the reaction rates determined to be first-order at low concentrations (<200 ppm), zero-order at high concentrations (>400 ppm), and fractional-order in the intermediate concentration range for H2S in the inlet waste gas. The overall performance of the biofilter system and changes in compost properties were investigated for 200 days of operation. The compost biofiiter showed good buffering capacities to variations in gas flow rate and pollutant (H2S) loading impacts. Hydrogen sulfide removal efficiencies exceeding 99.9% were consistently observed. System acidification and sulfate accumulation were identified as inhibitors of required biological activity. Routine washing of the compost effectively mitigated these deficiencies. System upset was determined to be caused by compost dry-out or system overloading. Methods were developed to provide for recovery of contaminated filter material.

Yonghua Yang

Eric R. Allen

Biofiltration Control of Hydrogen Sulfide 2. Kinetics, Biofilter Performance, and Maintenance

生物过滤控制硫化氢 2. 动力学、生物过滤器性能与维护

A recycling exposure system, which has characteristics of dynamic and static systems, has been designed and constructed for calibrating passive sampling tubes. This system is very easy to set up and maintain. Organic vapors inside the system are generated by syringe injection, and homogeneous vapors are circulated by a metal-bellows pump. The concentrations of light hydrocarbons (e.g., isoprene) may decrease slightly after circulating for longer than 10 hours; however, this system is very stable for C5−C8 hydrocarbons for at least eight hours. The system has been used successfully to calibrate Perkin-Elmer diffusion tubes packed with Chromosorb 106 for collecting benzene vapor at low exposure doses (<70 ppmv•min). The entire system can be easily and effectively cleaned by circulating through a U-tube packed with activated carbon.

Xu-Liang Cao

C. Nicholas Hewitt

An Exposure System for the Calibration of Passive Samplers to Volatile Organic Compounds at Low (ppbv) Concentrations

用于低浓度（ppbv）挥发性有机化合物被动采样器校准的暴露系统

Publication Information	Publisher: Taylor and Francis Ltd.，Publishing cycle: ，Journal Type: journal，Open Access Journals: No
Basic data	Year of publication: 1993，Proportion of original research papers: ，Self Citation Rate:， Gold OA Rate:

Air and Waste

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