APCA Financial Statements for 1975-1976

Abstract

A wind tunnel study was completed to determine the effects the presence of a parapet and raised intake configurations have on the dilution of a pollutant between a rooftop stack and building intake. This study was the first to address the effects of building parapets and varying intake configurations. A study of this kind is desirable because it is common practice for architects to attempt to hide stacks with the use of a parapet in order to make industrial buildings more aesthetically pleasing. This is done with no thought to the effect it may have on the intended function of the stacks, which is dispersing gases away from the building to avoid contamination of ventilation air.

Three parapet configurations (no parapet and two different parapet heights) and two intake configurations (flush and raised) were investigated. The relative effects of the parapets and the raised intake configurations were also compared and contrasted for five stack heights, two stack locations, and four intake locations.

The parapets were found to produce a cavity zone that extends above the building's roof by as much as two times the physical height of the parapet; increasing stack height had little effect on dispersion until the stack extended beyond this cavity region. The independent use of the parapets and raised intake configuration decreased the number of dilutions occurring between stack and intake when compared to the no parapet and flush intake configurations in all cases. Also substantiated in this study is the widely accepted view that the effect of the parapet addition is to decrease the effective stack height by the parapet height itself.

The results of this investigation were then compared to existing wind tunnel-derived empirical models. The models tested were not able to predict the effects of varying stack height and of varying the relative distance between stack and intake on the dilution of a pollutant between stack and intake under the tested configurations.     

Practical Applications of Stacks to Minimize Pollution Problems

“Rules of thumb” for stack design have been developed for use on problems where extensive studies cannot be justified or where quantitative design data are unavailable. The application of these rules to a practical stack design problem is discussed. The IBM 704 computer has been used for rapid yet rigorous stack design studies. The computer procedures for design are discussed and its application to a practical problem is described in detail.     

Simulation of stack plume opacity

The visual impact of primary particles emitted from stacks is regulated according to stack opacity criteria. In-stack monitoring of the flue gas opacity allows plant operators to ensure that the plant meets U.S. Environmental Protection Agency opacity regulations. However, the emission of condensable gases such as SO3 (that hydrolyzes to H2SO4), HCl, and NH3, which may lead to particle formation after their release from the stack, makes the prediction of stack plume opacity more difficult. We present here a computer simulation model that calculates the opacity due to both primary particles emitted from the stack and secondary particles formed in the atmosphere after the release of condensable gases from the stack. A comprehensive treatment of the plume rise due to buoyancy and momentum is used to calculate the location at which the condensed water plume has evaporated (i.e., where opacity regulations apply). Conversion of H2SO4 to particulate sulfate occurs through nucleation and condensation on primary particles. A thermodynamic aerosol equilibrium model is used to calculate the amount of ammonium, chloride, and water present in the particulate phase with the condensed sulfate. The model calculates the stack plume opacity due to both primary and secondary particles. Examples of model simulations are presented for three scenarios that differ by the emission control equipment installed at the power plant: (1) electrostatic precipitators (ESP), (2) ESP and flue gas desulfurization, and (3) ESP and selective catalytic reduction. The calculated opacity is most sensitive to the primary particulate emissions. For the conditions considered here, SO3 emissions showed only a small effect, except if one assumes that most H2SO4 condenses on primary particles. Condensation of NH4Cl occurs only at high NH3 emission rates (about 25 ppm stack concentration).     

A new approach for biological online testing of stack gas condensate from municipal waste incinerators

A biological testing system for the monitoring of stack gas condensates of municipal waste incinerators has been developed using Euglena gracilis as a test organism. The motility, velocity and cellular form of the organisms were the endpoints, calculated by an image analysis system. All endpoints showed statistically significant changes in a short time when organisms were exposed to samples collected during combustion situations with increased pollutant concentrations. The velocity of the organisms proved to be the most appropriate endpoint. A semi-continuous system with E. gracilis for monitoring stack gas condensate is proposed, which could result in an online system for testing stack gas condensates in the future.     

Estimates of Ground Level TSP,S02 and HCI for a Municipal Waste Incinerator to be Located at Tynes Bay—Bermuda

The computer model Industrial Source Complex Short Term (ISCST) was used to study the stack emissions from a refuse Incinerator proposed for the island of Bermuda. The model predicts that the highest ground level pollutant concentrations will occur near Prospect, 800 m to 1000 m due south of the stack. We installed a portable laboratory and instruments at Prospect to begin making air quality baseline measurements. By comparing the model’s estimates of the incinerator contribution to the background levels measured at the site we predict that stack emissions will not cause an Increase In TSP or SO₂. The incinerator will be a significant source of HCI to Bermuda air with ambient levels approaching air quality guidelines.     

Dioxin analysis in stack emissions, slags and the wash water circuit during high-temperature incineration of chlorine-containing industrial wastes; Part 2

PCB's and polychlorobenzene sumps have been incinerated in a high-temperature installation. The working conditions, wastes, sampling methods and analysis of the stack emissions, slag and wash water are described. No 2,3,7,8-TCDD and only ppt-traces of some PCDD congeners were detected in the stack emission. The performance criteria of the incinerator and the more important sampling procedures are discussed.     

PCBs contributions to the total TEQ released from Korean municipal and industrial waste incinerators

Non-ortho and mono-ortho polychlorinated biphenyls (PCBs) were determined in the stack gases and the fly-ash from nine Korean municipal solid waste incinerators (MSWIs). Soil samples collected near MSWI and industrial waste incinerator (IWI) sites were also examined for PCBs. The PCBs levels in the stack gas samples ranged between 0.0046 and 12.0 TEQ-ng/Nm³. The PCB homologue profiles were distinct for the stack gas samples and different from the fly-ash. PCBs levels in soil samples collected near MSWIs and IWI ranged between 0.86 and 19.73 TEQ-ng/g with background levels of 0.17 TEQ-ng/g. The lower chlorination PCBs were dominant in the soil samples. The stack emission PCBs homologue patterns were compared to those detected in the soil samples. The findings suggest that localized point sources as well air mass movement contribute to the deposition of PCBs onto soil.     

Water flume study of the enhancement of buoyant rise in pairs of merging plumes

When multiple stacks are grouped or ganged together at a site, the effluent plumes are often observed to merge downwind, forming a single buoyant plume whose rate of rise is enhanced relative to the rise of the plumes individually. The magnitude of this rise enhancement depends on many factors, and the few available models for rise enhancement do not always agree with one another. In the present study the rise behaviour of pairs of merging, buoyant plumes was studied by physical modelling in a water flume at 1:500 scale. The experiments were conducted at several stack separation distances and various exit velocity ratios for stack pairs aligned with, or perpendicular to, the ambient flow. Limited experiments were also done with the stacks aligned at other angles to the flow. The stack releases were made buoyant by heating the source water, and the resulting plumes were measured with an array of sensitive temperature probes. From these measurements it was possible to determine the plume structure and rise rates. For small stack separations when the stacks are aligned with the ambient flow, the experimental results show that the enhanced rise is close to, and sometimes above, the maximum theoretical rise enhancement factor of 2^1/3. For the perpendicular orientation there is little or no rise enhancement. The rise enhancement for other stack orientations is somewhere between these two extremes. A plausible physical explanation for the observed behaviour is given, based on initial momentum shielding and line vortex dynamics in the merging plumes.     

The Stack Height Requirements Implicit In the Federal Standards of Performance For New Stationary Sources

The promulgation of Federal standards of performance for certain classes of new stationary sources requires that such sources have minimum stack heights to meet also the requirements of national air quality standards. The determination of minimum stack height is complicated by the fact that the performance and air quality standards are stated on different averaging time bases; that the extent of preemption of the assimilative capacity of the air by any individual source will vary among jurisdictions and, in some cases, among different geographic areas of a single jurisdiction; and that some new sources will be designed to emit appreciably less than the performance standard requirement. However, these complications can be resolved and equations and charts prepared from which minimum stack height can be selected.     

Analytical procedures to assay environmental samples for PCDD/PCDF, PHA, PCB, chlorobenzenes (CB) and chlorophenols (CP)

Sample extracts from each section of a blank stack sampling train are portioned into two fractions, one to be used for PCDD/PCDF and PCB/CB analysis and the other for PAH/CP. The results of recovery studies for spiked compounds are presented. Developed protocols will be applied to future stack sampling programs and other environmental monitorings.     

Emission Standards for the Control of Solid Particles,A New Approach by New Jersey

Existing chapters of the New Jersey Air Pollution Control Code are described, followed by an explanation of a proposed new chapter to control emissions of coarse solid particles and fine solid particles from industrial processes. The chapter is designed to limit dustfall of coarse particles off the premises of the emitter to WO tons per square mile per year, and the methods used to relate this criterion to stack emissions are explained. Fine particles, suspended in the air off the premises, are limited to 0.615 milligrams per cubic meter during average weather conditions. Measures taken for the protection of buildings, where the plant property line is less than 10 stack heights from the base of the stack, are described.     

The Validity of Several Plume Rise Formulas

The ground level concentration of pollutants downwind of a tall chimney decreases as the effective height of the stack increases. The effective height of the stack is the actual height plus the rise of the plume center-line due to momentum and buoyancy of the effluent. Over twenty formulas to predict plume rise from stack and meteorological parameters have been proposed; none is uniformly accepted. In this paper, 711 plume rise observations were used to test the ability of fifteen of the published and commonly used formulas to predict plume rise. The plume rise data were obtained from single stacks whose heat emission rate varied over four orders of magnitude. None of the formulas tested was found to be significantly better than the others. Research was performed under the auspices of the U.S. Atomic Energy Commission.     

Simulation of Stack Plume Opacity

ABSTRACT

The visual impact of primary particles emitted from stacks is regulated according to stack opacity criteria. In-stack monitoring of the flue gas opacity allows plant operators to ensure that the plant meets U.S. Environmental Protection Agency opacity regulations. However, the emission of condensable gases such as SO₃ (that hydrolyzes to H₂SO₄), HCl, and NH₃, which may lead to particle formation after their release from the stack, makes the prediction of stack plume opacity more difficult.

We present here a computer simulation model that calculates the opacity due to both primary particles emitted from the stack and secondary particles formed in the atmosphere after the release of condensable gases from the stack. A comprehensive treatment of the plume rise due to buoyancy and momentum is used to calculate the location at which the condensed water plume has evaporated (i.e., where opacity regulations apply).

Conversion of H₂SO₄ to particulate sulfate occurs through nucleation and condensation on primary particles. A thermodynamic aerosol equilibrium model is used to calculate the amount of ammonium, chloride, and water present in the particulate phase with the condensed sulfate. The model calculates the stack plume opacity due to both primary and secondary particles. Examples of model simulations are presented for three scenarios that differ by the emission control equipment installed at the power plant: (1) electrostatic precipitators (ESP), (2) ESP and flue gas desulfurization, and (3) ESP and selective catalytic reduction. The calculated opacity is most sensitive to the primary particulate emissions. For the conditions considered here, SO₃ emissions showed only a small effect, except if one assumes that most H₂SO₄ condenses on primary particles. Condensation of NH₄Cl occurs only at high NH₃ emission rates (about 25 ppm stack concentration).     

Performance testing of a multimetals continuous emissions monitor

A prototype instrument, designed for continuous monitoring of hazardous air pollutant metal emissions in the stack gases of waste incinerators and industrial furnaces, has undergone a performance evaluation that included a relative accuracy test audit. The test results confirmed the instrument's ability to accurately measure stack gas metal concentrations and thus validate the applicability of the candidate technique for compliance assurance monitoring for the specific source involved. The analytical accuracy of this system, documented during the recent test exercise, represents a significant improvement in performance relative to that previously achieved, and can be attributed with certainty to the recent implementation of a shrouded nozzle sampling system. By reducing deposition losses of particulate matter in the extracted stack gas stream to acceptable levels, presentation of a more representative sample stream to the elemental analyzer has been accomplished. The present paper discusses the design and operation of the multimetals continuous emissions monitor (MMCEM), the shrouded nozzle sampling system, and the results of recent performance testing.     

Estimation and characterization of unintentionally produced persistent organic pollutant emission from converter steelmaking processes

Unintentionally produced persistent organic pollutants (UP-POPs) including polychlorinated dibenzo-p-dioxins, and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), and polychlorinated naphthalenes (PCNs) were characterized and quantified in stack gas and fly ash from the second ventilation systems in five typical converters in five different steelmaking plants. The 2378-substituted PCDD/Fs (2378-PCDD/Fs) and dioxin-like PCB (dl-PCBs) toxic equivalents (TEQs) were 1.84–10.3 pg WHO-TEQ Nm^?3 in the stack gas and 5.59–87.6 pg WHO-TEQ g^?1 in the fly ash, and the PCN TEQs were 0.06–0.56 pg TEQ Nm^?3 in the stack gas and 0.03–0.08 pg TEQ g^?1 in the fly ash. The concentrations of UP-POPs in the present study were generally lower than those in other metallurgical processes, such as electric arc furnaces, iron ore sintering, and secondary metallurgical processes. Adding scrap metal might increase UP-POP emissions, indicating that raw material composition was a key influence on emissions. HxCDF, HpCDF, OCDF, HpCDD, and OCDD were the dominant PCDD/Fs in the stack gas and fly ash. TeCB and PeCB were dominant in the stack gas, but HxCB provided more to the total PCB concentrations in the fly ash. The lower chlorinated PCNs were dominant in all of the samples. The 2378-PCDD/F, dl-PCB, and PCN emission factors in stack gases from the steelmaking converter processes (per ton of steel produced) were 1.88–2.89, 0.14–0.76_, and 229–759 μg t^?1, respectively.     

Comparison of variability in dioxin and furan data acquired using single train and simultaneous multiple train stack sampling methods

The variance of polychlorinated dibenzo-p-dioxin (PCDD; dioxin) and polychlorinated dibenzofuran (PCDF; furan) data obtained from single- and simultaneous multiple train methods was compared. Single train triplicate data were used from 4 stack tests obtained from a long dry kiln cement plant and 18 stack tests from a municipal solid waste (MSW) incinerator. Data from the American Society of Mechanical Engineers (ASME) report Reference Method Accuracy and Precision (ReMAP) (Lanier and Hendrix, 2001) were used for the simultaneous multiple samples, which accounted for 27 data points. Nineteen data points were acquired from an ASME research facility, 5 from a MSW incinerator unrelated to the single train MSW incinerator, and 3 from a lightweight aggregate kiln (LWAK). The ReMAP procedure was used to determine the relationship between the standard deviation and the concentration of the single train and simultaneous multiple train data. Results indicated that there was benefit from the use of simultaneous multiple train sampling for concentrations above 129 pg toxic equivalency (TEQ)/m³. There was no indication of benefit from the use of simultaneous multiple train sampling at concentrations below 129 pg TEQ/m³.

Implications:Precision of stack sampling data can be the difference between meeting and failing compliance limits. Generally, three dioxin/furan samples are acquired when stack sampling to meet compliance regulations. A reliable estimation of the data’s true concentration is not possible with this small amount of data. Increasing the precision decreases the chance that the acquired concentration deviates greatly from the true concentration. Facilities that use the appropriate stack sampling method will benefit by either improved data precision or minimal stack sampling expenses. The observations made suggest that facilities that are expected to have dioxin/furan concentrations above 129 pg TEQ/m³ would increase the precision of samples by using simultaneous multiple train sampling.     

Panel Discussion

A stack design procedure is developed which accounts for the effect of plume interception by downwind buildings, and which provides information on effluent concentrations in a form useful to planning authorities. The information presented in this paper is directed to engineers carrying out stack designs for locations where downwind buildings are of comparable height to the stack. A wind tunnel investigation using tracer gas techniques indicates that, for a plume at building height, downwash on the upwind face of a building causes the high concentrations observed near the roof to be transported to ground level. The effect of a plume on elevated points is determined by the concept of the minimum descent height of the maximum allowable ambient concentration isopleth. This minimum descent height, computed using Gaussian plume dispersion theory, defines a building height below which pollutant concentrations will always lie within safe limits. A case study is presented for the use of the design procedure for a small thermal power plant in an urban area.     

Performance Testing of a Multimetals Continuous Emissions Monitor

ABSTRACT

A prototype instrument, designed for continuous monitoring of hazardous air pollutant metal emissions in the stack gases of waste incinerators and industrial furnaces, has undergone a performance evaluation that included a relative accuracy test audit. The test results confirmed the instrument's ability to accurately measure stack gas metal concentrations and thus validate the applicability of the candidate technique for compliance assurance monitoring for the specific source involved. The analytical accuracy of this system, documented during the recent test exercise, represents a significant improvement in performance relative to that previously achieved, and can be attributed with certainty to the recent implementation of a shrouded nozzle sampling system. By reducing deposition losses of particulate matter in the extracted stack gas stream to acceptable levels, presentation of a more representative sample stream to the elemental analyzer has been accomplished. The present paper discusses the design and operation of the multimetals continuous emissions monitor (MMCEM), the shrouded nozzle sampling system, and the results of recent performance testing.     

厌氧折流板式微生物燃料电池堆影响因素研究

微生物燃料电池(MFC)中输出电压/电流的提升,以及反应器体积的扩展放大是其工程化应用的关键。本文构建了一个总体积为6.4 L的新型厌氧折流板式微生物燃料电池堆(ABSMFC)。以葡萄糖作为底物,探讨了阳极材料、液面高程差和水力停留时间(HRT)等因素对ABSMFC性能的影响。结果表明,碳纤维毡作为阳极时,电池单体外电路平均分压(R_(ex)=1 000Ω)为210 mV,填充石墨颗粒后增加到319.8 mV。格室间存在液面高程差时,电池单体、串联和并联的功率密度分别为207.1、181.1和215.7 mW/m~2,当无液面高程差(即水力相连)时为205.8、69.5和151.5 mW/m~2。4个电池单体串联和并联连接时,HRT对ABSMFC的产电稳定性无影响,溶解性COD的去除率和库仑效率均随HRT的增加而升高,且并联效果优于串联。