The Use of Electrostatic Precipitators on Municipal Incinerators

Despite this country’s scientific advances, most communities in the United States are still disposing of solid wastes the way they did 50 years ago. The problem is advancing faster than the solution. Less than half the cities in this country with populations over 2500 dispose of their wastes by an approved sanitary and nuisance-free method. Do you realize that every 60 seconds people in the United States drop 251 tons of trash into their garbage cans. At the end of the day, 362,000 tons have accumulated. This means each of the 190 million people in the US disposes of 43½ lb of rubbish daily. By the year 2000 population is expected to double, while the per capita rate of increase in refuse production rises about 2% annually.

As the population booms and spreads to the suburbs, and suburbs expand into further suburbs, we will rapidly use up the land once used for waste disposal. Thus, sanitary landfill sites will disappear because by the year 2000 three-fourths of our population will live in urban areas.

The answer to this enormous problem faced by large and small communities is central incineration. Only this system can provide a maximum reduction in the volume of refuse. It is for this reason that communities are turning to incineration as the best solution. However, a growing public awareness plus changing municipal, state, and federal laws necessitate the need for a modern incineration plant that incorporates the most advanced and proved method of air pollution control. Where efficiencies of 60 to 80% were acceptable in the past, 90 to 95% are sought at present, and soon 96 to 99% will be required.

This paper deals with the effective control of particulate emissions from municipal incinerator exhaust gases.     

The Development of Open Pit Incinerators for Solid Waste Disposal

A discussion is presented of a newly developed incinerator for the disposal of solid wastes. It is distinguished from conventional types by its open top, and features a system of closely spaced nozzles admitting a screen of high-velocity air over the burning zone. Results, with a variety of solid industrial wastes, show high burning rates, leading to complete combustion and high flame temperature.     

Unsolved Problems with Flue-FED Incinerators

At the beginning of the federal program in 1955, air pollution was viewed as a technical challenge. While technical problems remain, emphasis is shifting toward the social challenge. The degree of federal assistance now available to states and municipalities, under the Clean Air Act, is of broadened scope and higher order of magnitude; it is not confined to technical considerations, but has been expanded to take cognizance of political and economic obstacles that often block the path toward better air pollution control.     

The Cost Estimation of Thermal and Catalytic Incinerators for the Control of VOCs

In an earlier paper, major commercially available incinerator technologies designed to treat dilute waste gas streams containing volatile organic compounds (VOCs) were described in a qualitative comparison. In addition, a simplified procedure was outlined through which important sizing parameters could be calculated given certain information about the waste gas. This paper describes the use of these parameters in developing a study (±30percent) cost estimate for the total capital investment and the total annual costs incurred in treating a waste stream of volatile organic compounds (VOCs). An illustrative problem used in the former paper is completed here in order to contrast some of the economic differences between thermal and catalytic incinerator systems.     

Prospects for Reducing Particulate Emissions from Large Incinerators

Conventional types of municipal incinerators generate enormous quantities of stack gas because of high excess air and high temperatures. Under these conditions the size and cost of equipment to clean the flue gas to low dust contents are large. By burning the refuse in boiler furnaces at low excess air, and generating steam, the volume of flue gas to be cleaned is reduced to a minimum. Where high efficiency of flue-dust collection is required, steam generation from refuse firing permits a major saving on the cost of dust collection.     

Thermal and Catalytic Incinerators for the Control of VOCs

Abstract

The emission of Volatile Organic Compounds (VOCs) is attracting increasing concern both from the public and by government agencies. Among the many available control technologies for the treatment of VOC containing waste streams, incineration offers an ultimate disposal strategy rather than a means for collecting or concentrating the offending compounds. This paper describes the major, commercially available thermal and catalytic incinerator systems that are designed to treat dilute, VOC containing gas streams. Qualitative guidelines are presented whereby the technologies can be compared. In addition, an example waste stream is used to illustrate a simplified procedure for calculating the material and energy balances for each of the incinerators. The resulting parameters will be used in a companion paper to estimate the capital and operating costs associated with each design. In this manner, a first estimate can be obtained of the costs of cleaning a waste stream containing low levels of VOCs.     

Determination and Evaluation of Stack Emissions From Municipal Incinerators

A comprehensive incinerator air pollution control testing program was recently completed in New York City, and the results contain valuable particulate and gas sampling data. The information, which was obtained from a large number of test runs, is especially valuable since there is a shortage of reliable, valid test data of this nature. Since the test data now presented involved 1000 ton/day incinerators, which operate 24 hr/day, 6 days/wk, it is significant design criteria for consideration when upgrading a large incinerator or building a new one. The tests also provide information concerning the nature and concentration of gaseous constituents in the incinerator stack effluent.     

Particulate Emissions from Apartment House Boilers and Incinerators

The body of information presented in this paper is directed to researchers in stack testing methodology and to those concerned with reduction of emissions through equipment upgrading programs. Extensive testing was done using the U.S. Environmental Protection Agency’s Method 5 stack sampling train to obtain emission factors for existing apartment house boilers and incinerators in the City of New York. In addition to calculating emission factors, stack emission data were examined to compare results of simultaneous emission tests and to compare the dry particulate catch of the sampling train with the total particulate catch which included the impinger catch. Conclusions reached as a result of the testing were that published emission factors for boilers burning moderately high-sulfur residual oil are applicable to New York City boilers burning low-sulfur residual oil. In addition, it was found that the back half of the sampling train—the impinger section—collects a relatively constant amount of material when sampling oil-fired boilers. This may be due to absorption of S0₂ and S0₃ in the impingers and the subsequent formation of sulfuric acid. Comparison of simultaneous boiler tests indicated that the sampling train may be sensitive to variations in operating personnel, sampling conditions, and boiler operation. From tests of on-site incinerators, it was determined that previously published emission factors may be too high for well maintained and properly operated incinerators. The back half particulate catch was found to be relatively large which may have resulted from condensation of unburned organics from the burning waste material.     

Evaluation of Continuous Performance Monitoring Techniques for Hazardous Waste Incinerators

This paper discusses monitoring the waste destruction efficiency of hazardous waste incinerators. The particular problem is to ensure that incinerators do not release, without detection, significant quantities of waste as a result of operating fluctuations or equipment degradation. To detect these conditions, continuous, automated, and real-time source monitoring is required. Detection of degraded performance by monitoring and measuring waste compounds directly is not presently possible on a continuous basis. An alternative is to use commercially available continuous monitors to measure combustion intermediates (e.g., CO or hydrocarbons) and thereby infer waste destruction efficiency. Required, however, is a correlation between the emission of intermediates and the emission of waste. In this paper, the response of a number of these continuous monitors is compared with waste destruction efficiency measurements from a laboratory scale, liquid-spray incinerator operated on fuel oil doped with model waste compounds: benzene, chlorobenzene, acrylonitrile, and chloroform. Total hydrocarbon and CH₄ measurements are found to vary with waste emission in a nearly linear manner; however, a substantial increase in CO emission occurs before a significant amount of waste is released. These results suggest that CO may serve as an indicator of the approach of waste release, while total hydrocarbons may provide an indicator of immediate waste release.     

Emissions of Chlorinated Organics from Two Municipal Incinerators in Ontario

In this paper the results of sampling for trace chlorinated organics at two municipal refuse incinerators in Ontario are presented. The information may be of Interest to individuals concerned with the assessment of PCDD/PCDF (polychlorinated dibenzo-p-dioxin/polychlorinated dibenzofuran) emissions from incineration of refuse and their impact on the energyfrom- waste program. PCDDs, PCDFs, PCBs (polychlorinated biphenyls), CBs (chlorobenzenes) and CPs (chlorophenols) were quantified in all process streams including refuse, ash and stack emissions. Manual sorting of refuse and collection of ash samples were carried out simultaneously with three 24-hour continuous stack sampling tests at each plant. The results suggested that the total output of PCDDs and PCDFs varied proportionately with their input at both incinerators. However, the input of PCDDs/PCDFs could not account for their total output. The chemistry of PCDDs/PCDFs in the input and output streams were different in that only heptachlorinated and octachlorinated species were present in significant quantities in the refuse while lower chlorinated species were predominant in stack emissions and ash streams. There was no correspondence between the Input of PCBs/CBs/CPs and the output of PCDDs/PCDFs. The output of PCDDs/PCDFs, however, varied Inversely with the total output of PCBs/CBs/CPs, suggesting that the latter compounds could have been partially responsible for the formation of PCDDs and PCDFs. The PCDF emissions were also affected by combustion conditions; they were higher in magnitude and consisted of predominantly tetrachlorinated and pentachlorinated species at the plant where the combustion temperatures were lower.     

Concentration of Atmospheric Pollutants in the Gaseous Emissions of Medical Waste Incinerators

ABSTRACT

The purpose of this paper is to quantify the production of medical waste from a general hospital and to evaluate the atmospheric pollutant concentrations in gaseous emissions associated with its incineration. A 3.8 kg (bed.day)^-1 production of medical waste was estimated for 1998; its incineration is related with an ash production of 0.3-0.4 kg (bed.day)^-1. The concentrations of atmospheric pollutants were estimated using emission factors, comparing the effluents with and without control of atmospheric pollutants. The calculated concentrations were compared with the emission limits established by Portuguese legislation. The results indicate that, if there is no control of atmospheric pollutants, their concentrations exceed the established limits. This is observed even if correct operation and maintenance procedures are used. The emission concentrations of dioxins are higher than the Portuguese emission limit, which is particularly worrying due to the high toxicity of some of these compounds. Generally, it is possible to reduce pollutant concentrations if appropriate control equipment is used. The conclusions obtained clearly justify the great concern regarding air pollution associated with medical waste incinerators currently operating in Portugal.     

An Evaluation of the Semi-VOST Method for Determining Emissions from Hazardous Waste Incinerators

The Semi-Volatile Organic Sampling Train method was investigated to determine its reliability and to determine the bias and precision of the method when used to determine emissions from hazardous waste incinerators. Experiments showed that the matrix and sampling variables usually involved in sampling emissions from a hazardous waste incinerator had no significant effect on the recovery of 11 different organic compounds. Significant losses of the sampled compounds can occur during sample preparation. The degree of loss appears to be directly related to the compounds, vapor pressure. These losses can be corrected for by adding deuterated surrogates to the sample and analyzing the surrogates along with the native compounds.

The bias determination was based on dynamic spiking of the sampling train with five deuterated organic compounds selected from Appendix VIII of the Resource Conservation and Recovery Act regulations. The results show biases of from -1 ± 8 percent to -18 ± 27 percent for chlorinated and nonchlorinated compounds. Pyridine, a water-soluble compound, showed a larger bias of-29 ± 13 percent. Particular attention to the recovery of water soluble compounds is necessary to minimize bias in their determinations. Further work is needed to determine the reliability of laboratory-determined retention volumes that are used to determine sampling conditions.     

Generation of PCDD/F in Fly Ash from Municipal Solid Waste Incinerators

Abstract

Fly ash from municipal solid waste incinerators (MSWIs) has been characterized in terms of polychlorinated dibenzyl-p-dioxin and polychlorinated dibenzofuran (PCDD/F) content. Increasing values of PCDD/Fs have been found to correlate with decreasing temperatures of sampling points in flue gas treatment lines of the plants, confirming other researchers’ findings about temperature as the major controlling parameter for the PCDD/F formation. Measured PCDD/F ratios show that de novo synthesis is the dominant formation mechanism. The increasing trends of particulate-bound PCDD/Fs can be explained not only through the dominant de novo synthesis process but also considering the adsorption of gaseous PCDD/Fs on fly ash deposits, even outside the typical de novo synthesis temperature ranges. The effective role of a post-combustor unit, imposed by Italian law to destroy PCDD/Fs, also needs to be carefully reconsidered.     

Correlation of PCDD/F Emissions with Operating Parameters of Municipal Solid Waste Incinerators

ABSTRACT

Municipal solid waste incinerator (MSWI) operators frequently have expressed the need for an indirect indication of the expected production of PCDD/F and associated abatement procedures through a possible correlation with other real-time data, through using marker pollutants (e.g., penta/hexachlorinated aromatics), or through other indications. Since real-time measurement of PCDD/F is impossible, a correlation of PCDD/F emissions with other operating parameters could help in achieving these goals. Literature data of large-scale MSWIs concerning these correlations are scarce and seldom conclusive. Extensive data of Flemish MSWIs are used to statistically assess possible correlations of PCDD/F and other operating parameters.

The effect of temperature in the electrostatic precipita-tor (ESP) is of major importance. When converting values measured between 180 and 270 °C to a reference temperature of, for example, 230 °C, PCDD/F concentrations achieve nearly constant values, stressing that the major correlating parameter is the temperature of the ESP. High temperatures that enhance de novo synthesis should be avoided.     

Impact of Polycyclic Aromatic Hydrocarbon Emissions from Medical Waste Incinerators on the Urban Atmosphere

Abstract

In this study, polycyclic aromatic hydrocarbon (PAH) emissions from two batch-type medical waste incinerators (MWIs), one with a mechanical grate and the other with a fixed grate, both operated by a medical center, were assessed. Both MWIs shared the same air-pollution control devices (APCDs), with an electrostatic precipitator and a wet scrubber installed in series. Results show that when APCDs were used, total PAHs and total benzo- [a]pyrene equivalent (total BaP_eq) emission concentrations of both MWIs were reduced from 2220 to 1870 µg/m³ and 50 to 12.4 µg/m³, respectively. We used the Industrial Source Complex Short Term model (ISCST) to estimate the ground-level concentrations of the residential area and the traffic intersection located at the down-wind side of the two MWIs. For the traffic intersection, we found both total PAHs and total BaP_eq transported from MWIs to both studied areas were not significant. For the residential area, similar results were found when APCDs were used in MWIs. When APCDs were not included, we found that total PAHs transported from MWIs accounted for <12%, but total BaP_eq accounted for >90%, of the on-site measured concentrations. These results suggest that the use of proper APCDs during incineration would significantly reduce the carcinogenic potencies associated with PAH emissions from MWIs to the residential area.     

The Lead Dioxide Estimation Of Sulfur Dioxide Pollution

A new system of measuring sulfation is presented. Because of its simplicity, operation of large sulfation networks can be accomplished at extremely nominal costs. Because of increased sensitivity, present 1 -month sampling time intervals may be shortened to approximately 1 day. Use of this system will permit more definitive investigations of the relationship of sulfation to sulfur dioxide concentration.