Maximum Achievable Control Technology Research Articles

Method development and implementation for co-planar polychlorinated biphenyls (PCBs)

The Emission Measurement Center (EMC) in the Environmental Protection Agency's Office of Air Quality Planning and Standards was directed to conduct an emissions test program at a sewage sludge incinerator in support of a Maximum Achievable Control Technology (MACT) standard. One pollutant category of concern at these facilities was polychlorinated biphenyls, or PCBs. An objective of the test program was to measure co-planar PCBs in the incinerator emissions, the sewage sludge introduced to the incinerator, and the scrubber water effluent used in controlling the incinerator emissions. Co-planar PCB congeners are those having four or more chlorine atoms with only a few substitutions in the ortho positions, i.e. positions designated 2, 2′, 6, and 6′. Thirteen PCB compounds are sometimes referred to as the “WHO PCBs,” because the World Health Organization (WHO) has derived toxic equivalency factors for these congeners. Studies have shown that these dioxin-like compounds can react with the aryl hydrocarbon receptor. This same reaction is believed to initiate adverse health effects for dioxin and furan congeners. In order to conduct the co-planer PCB testing, the EMC had to develop analytical methods that could measure the 13 co-planar PCBs. The purpose of the test program was to develop, evaluate, and implement analytical test methods capable of measuring co-planar PCBs in three matrices: incinerator stack gases, sewage sludge, and scrubber water effluents. The paper summarizes the initial development work that was performed in preparation of analytical test protocols that could measure co-planar PCBs in air, water, and sludge matrices. Following the method development, a MACT emissions test program was conducted at a sewage sludge facility in July 1999 and these data are also summarized in the paper.

Air Pollution from Secondary Aluminum Production: Determining the Applicability of MACT Requirements

EPA's Maximum Achievable Control Technology rule for secondary aluminum production is intended to substantially reduce emissions of hazardous air pollutants. It may also impose significant costs on affected facilities. © 2001 John Wiley & Sons, Inc.

Control of mercury emissions from coal-fired power plants: a preliminary cost assessment and the next steps for accurately assessing control costs

Mercury emissions from coal-fired power plants have been extensively evaluated for nearly 10 years to determine possible regulation by the Environmental Protection Agency (EPA). Under a court order, a determination will be made on whether it is appropriate and necessary to regulate toxic air pollutant emissions (focusing on mercury) from coal-fired utility boilers by December 15, 2000. If it is determined that regulations are necessary, then the regulatory process will have a fixed timetable. A proposed regulation will be due no later than December 15, 2003, and promulgated no later than December 15, 2004. The utility industry regulatory compliance must be in place by December 2007 since the Clean Air Act requires that sources come into compliance with Maximum Achievable Control Technology (MACT) 3 years after promulgation of the regulations. While it is recognized that the main driver for regulation is the potential risk to human health and that this risk is currently being examined by a number of health-based organizations, the actual form of any regulation would likely be dependent upon the availability of cost-effective control technologies. Furthermore, the diverse nature of the coal-fired utility industry will likely limit the applicability and cost-effectiveness of any given technology for the current boiler population. In light of a potential regulatory determination, this paper examines a few control options that warrant further consideration. A preliminary assessment of mercury capture technologies and associated costs is conducted for sorbent injection technology. Sorbent-based technologies that may be amenable for mercury control include: (1) sorbent injection with and without spray cooling upstream of existing particulate control devices (i.e., electrostatic precipitators and fabric filters); and (2) sorbent injection with and without spray cooling associated with additional control devices designed to augment particulate collection in a primary particulate control device. Important design criteria for each of the control systems are critically assessed for operability, maintainability, and reliability, with the projected impacts of the control system on power plant operations being evaluated. The sorbent-based technology discussed in this paper focuses on the injection of activated carbon associated with the various particulate control devices used in the utility industry. The paper also addresses the next steps and revisions needed to accurately assess possible cost impacts to the utility industry as the mercury control options mature in their development.

Removal of products of incomplete combustion with carbon

Carbon injection and carbon beds have been used in Europe for the control of incinerator polychlorinated dibenzo- p-dioxin (dioxin) and polychlorinated dibenzofuran (furan) emissions since the 1980s. In the April 1996 proposed Hazardous Waste Combustor Maximum Achievable Control Technology standards, the US Environmental Protection Agency identified carbon injection as Beyond-the-Floor control technology for dioxin emissions from hazardous waste incinerators. In addition to dioxins and furans, data from hazardous and municipal waste incinerators have shown that carbon injection or carbon bed control will also reduce emissions of other products of incomplete combustion (PICs). This paper will qualitatively discuss the theoretical aspects of the carbon adsorption of PICs at baghouse and electrostatic precipitator temperatures and flue gas concentrations of parts per million to billion or lower. A summary of data on PIC removal with carbon from hazardous and municipal waste incinerators is also presented. Most of the carbon-PIC data described is for non-dioxin PICs. The emphasis in this paper is on non-dioxin PICs.

Optimized design and operating parameters for minimizing emissions during voc thermal oxidation

The Clean Air Act (CAA) Amendments of 1990 are intended to reduce emissions of volatile organic compounds (VOCs) by 70 to 90%. They specifically designate 189 compounds as hazardous air pollutants (HAPs). The EPA estimates that the aerospace industry generates 208,000 tons per year of HAPs plus an additional 145,000 tons per year of VOCs. Maximum Achievable Control Technology (MACT) standards for regulating HAP emissions from the aerospace industry were proposed by the EPA. The most common HAPs found in the aerospace industry are glycol ethers, xylene, toluene, methyl ethyl ketone, trichloroethane, and methyl isobutyl ketone. Most HAP emissions come from clean-up solvents. Thermal oxidation systems play, and will continue to play, a prominent role in meeting CAA-mandated VOC and HAP emission-reduction targets. According to a study conducted for the American Institute of Chemical Engineers in 1993, oxidation systems are projected to be the technology of choice in 43% of the applications requiring VOC reduction. 1 Thermal oxidation systems can be applied to 80% of the compounds classified as HAPs under the CAA. On the one hand, thermal oxidation of VOCs is a very simple process. Organic compounds are burned to innocuous by-products. But on the other hand, proper design principles must be applied to ensure complete destruction of the organics while minimizing formation of undesirable by-products. Both design and operating parameters affect performance. This article discusses those principles used to maximize VOC destruction while minimizing the emissions of other pollutant species.

Best Available Control Technology (BACT) equivalent for the control of volatile organic emissions from paint dipping operations

This paper provides details of a study conducted to demonstrate an equivalent method of Best Available Control Technology (BACT) compliance for volatile organic emissions from dip coating of certain miscellaneous metal parts. The study was proposed to show that the total volatile organic compound (VOC) emissions from 3.8 lb of VOC/gallon coating formulations were no greater than the total VOC emissions from 3.5 lb/gallon formulations used under the same conditions for coating steel joists. The presumptive BACT standard enforced by the Virginia Department of Environmental Quality (DEQ) for dip coating of steel joists is 3.5 lb/gallon. The requirement of 3.5 lb/gallon was derived from the US Environmental Protection Agency Guideline Series Control of Volatile Organic Emissions from Existing Stationary Sources--Volume 6: Surface Coating of Miscellaneous Metal Parts and Products. On June 5, 1998 the source completed a 12 month, full scale comparison study under a consent order with the Virginia DEQ. During the study period, the source made daily measurements of product produced, paint used, and emissions from the control and test paint tanks, and reported data to EPA and the DEQ every two months. The study concluded that a 26 percent reduction in paint usage and a 20 percentmore » reduction in emissions was achieved in the test tanks using a 3.8 lb/gal coating compared to the control tanks using a 3.5 lb/gal coating. This study enables the source to achieve greater emission reductions than the presumptive BACT level and at the same time reduce painting costs by 34%. This study provides positive results for the environment, the steel joist industry, and the construction industry. This study could impact EPA's current Maximum Achievable Control Technology (MACT) rule development for Miscellaneous Metal Parts and Products and national VOC rules for this source category under Section 183(e) of the Clean Air Act.« less

A review of the role of plastics in energy recovery

This report reviews the major scientific investigations that have been reported world wide over the last ten years on the effect of plastics on the process and emission performance of energy from waste (EFW) facilities. Concentrations of contaminants in air emissions and other process residues measured during tests with added plastics are compared with concentrations during normal operations and with the stringent emission limits stipulated in municipal waste combustor standards and guidelines in Canada, the United States and the European Union. The emission limits in these standards and guidelines are based on the use of the best technology available (Maximum Achievable Control Technology (MACT) standards in North America and Best Available Technology (BAT) standards in Europe) and are amongst the most stringent in the world.

Maximum Achievable Control Technology: What a Shipbuilder Should Know for Environmental Compliance

The new system for the control of air toxics being developed by the United States Environmental Protection Agency called the "Maximum Achievable Control Technology" requires the development of technology based standards for Hazardous Air Pollutants within a specific industrial or commercial source category. This paper attempts to provide a comprehensive understanding of the rule and its applicability to shipbuilding and ship repair industry. The reasons for selecting California regulations as the shipyard maximum available control technology, the compliance procedures, the control technologies for paints as-supplied and paints as-applied and other general requirements under the MACT rule are discussed in detail in this paper.

National Annual Dioxin Emissions Estimate for Hazardous Waste Incinerators

ABSTRACT Reducing emissions of polychlorinated dibenzo-p-di-oxins and dibenzofurans, commonly known as di-oxins, is a high priority for environmental regulatory bodies throughout much of the world. In the United States, Section 112 (c)(6) of the Clean Air Act (CAA) requires the Environmental Protectio n Agency (EPA) to identify and control emissions from sources that are responsible for at least 90% of the overall emissions of seven targeted hazardous air pollutants, including dioxins.1 On April 19, 1996, the EPA proposed Maximum Achievable Control Technology (MACT) Standards for Hazardous Waste Combustors2 (HWCs). In that preamble, the EPA estimated annual dioxin emissions from the nation's hazardous waste incinerators (HWIs) to be 79 grams expressed as 2,3,7,8 tetrachloro dibenzo-p-dioxins (TCDD) international toxic equivalents (ITEQs). However, early EPA dioxin emission estimates from medical waste incinerators and cement kilns were significantly overestimated;3-5 so, the following independent national dioxin emissions estimate for HWIs was prepared. This estimate corrects the errors in the EPA's HWI emissions database, uses an updated inventory of HWIs in the United States, and applies statistical imputation techniques that take maximum advantage of the limited dioxin emissions data for HWIs.

High vacuum indirectly-heated rotary kiln for the removal and recovery of mercury from air pollution control scrubber waste

In the mining industry, mercury is often associated with various ores, particularly copper and lead. To meet Environmental Protection Agency (EPA) and State air emission regulations, smelters must remove mercury vapors from hot exhaust gases, usually through the use of scrubbing solutions. Most of the mercury is precipitated out of the waste scrubbing solutions as the sulfide and the sludge dewatered in a filter press. SepraDyne Corporation (Denton, TX, USA) has conducted pilot-scale treatability studies of dewatered acid plant blowdown sludge generated by a copper smelter using its recently patented high temperature and high vacuum indirectly-heated rotary retort technology [1]. This unique rotary kiln is capable of operating at internal temperatures up to 850°C with an internal pressure of 50 torr and eliminates the use of sweep gas to transport volatile substances out of the retort. By removing non-condensables such as oxygen and nitrogen at relatively low temperatures and coupling the process with a temperature ramp-up program and low temperature condensation, virtually all of the retort off-gases produced during processing can be condensed for recovery. The combination of rotation, heat and vacuum produce the ideal environment for the rapid volatilization of virtually all organic compounds, water and low-to-moderate boiling point metals such as arsenic, cadmium and mercury. Atmospheric oxygen can readily be reduced to very low concentrations within the kiln so that combustion does not take place. Initial concentrations of mercury in the waste ranged from 565 to 1260 mg/kg. The waste was processed in a 1.5 cubic foot capacity batch pilot unit at temperatures ranging from 427 to 649°C at a pressure of 76 torr. Total processing time ranged from 1.5 to 4.0 h. The processed material contained total mercury concentrations ranging from 0.065 mg/kg when processed at 649°C to an average of 2.2 mg/kg when processed at 427°C. The vaporized mercury was recovered as elemental mercury in a low temperature condenser [2]. Mercury emissions averaged approximately 6.5 μg/M 3, significantly below the Maximum Achievable Control Technology (MACT) standard of 40 μg/M 3. Based upon the success of these tests, a contract was let and a commercial scale unit was built. The 2-ton per batch commercial unit was installed at the copper smelter and began operations in late June 1998. As of the end of October, approximately 500 tons of mercury-contaminated acid blowdown sludge had been processed to below the specified treatment criteria of 10 mg/kg total mercury.

98/04191 Comparison of HAPs and hydrocarbon emissions

The proposed hazardous waste combustor (HWC) maximum achievable control technology (MACT) rule published in the April 19, 1996, Federal Register requested data and information on monitoring carbon monoxide (CO) or hydrocarbon (HC) emissions to control organic hazardous air pollutants (HAPs) emissions. The preamble of the proposed rule further states that monitoring HC emissions can also ensure that sources operate under {open_quotes}good combustion conditions.{close_quotes} As a result, the proposed rule is attempting to monitor organic HAP emissions as well as emissions from incomplete combustion (PICs). Because a large fraction of HAPs are organic compounds, using HC as an indicator for HAP emissions warrants further investigation. However, using HC as an indicator of PICs or good combustion is inconceivable because HC and PIC compound emissions depend on other process variables not related to hazardous waste fuel combustion completeness. The available database of HC, and volatile and semi-volatile organic HAP emissions indicates that HC-HAP correlations are difficult to make and HC-PIC emissions are non-existent. 1 ref., 16 figs.

Toward Development of A Laser-based Continuous Emission Monitor System for Toxic Metals in Off-gases

Laser-Induced Breakdown Spectrometry (L1BS) can meet the U.S. Environmental Protection Agency/s (EPA) proposed Maximum Achievable Control Technology (MACT) rules requirements for Be, Cd, Cr, Pb, and Sb. However, L1BS’ current limits of detection (LODs) for As and Hg are significantly higher than the LODs that EPA is seeking. The current Laser Optogalvanic Spectrometry (LOGS) laboratory LODs for airborne metal particles are comparable to or lower than the desired EPA MACT LODs for Cd, Cr, Hg, Pb, and Sb. We report our efforts to combine LOGS with LIBS to produce a near real-time metal emissions monitor that is capable of monitoring the volatile toxic metals that are regulated by EPA. During a field simulation test, LIBS, LOGS, and EPA Method 29 simultaneously determined the concentration of airborne metals in the off-gas. The LIBS results are found to be in reasonably good agreement with those of EPA Method 29. The LOGS real-time determinations were higher than those reported by either L1BS or EPA Method 29; this discrepancy is due (a) to a spectral interference with a two-photon sodium transition, and (b) to oversampling of large particles.

Science and policy in regulatory decision making: getting the facts right about hazardous air pollutants.

Hazardous air pollutants are regulated under Title III of the 1990 Clean Air Act Amendments. The Amendments replace the risk-based approach mandated in the 1977 Amendments with a prescriptive, technology-based approach requiring that maximum achievable control technology (MACT) be applied to all major industrial sources of 189 hazardous air pollutants. The change reflects political, rather than scientific consensus that the public health benefits justify the costs. The choice is put into perspective by looking at the interface between science and policy that occurs as part of regular decisionmaking. Particular emphasis is given to examining the interrelationships among facts (science), judgments (science policy), and policy (values) in the context of the risk assessment paradigm. Science and policy are discussed in relation to Title III, contrasting the political consensus for action with the scientific uncertainty about risks and benefits. It is argued that a balanced research program is needed to get the facts right about hazardous air pollutants, including research to meet statutory requirements, to reduce uncertainties in risk assessment, and to address strategic issues.

House seeks to block refinery toxics rule

The Environmental Protection Agency has issued a new regulation that would substantially reduce emissions of toxic pollutants from U.S. oil refineries. But a provision of a bill passed by the House would make it impossible for EPA to enforce the rule. The regulation would cut refinery emissions of 28 chemicals using maximum achievable control technology (MACT), affecting every existing and new refinery in the U.S. These compounds have been implicated in formation of ground-level ozone. The principal compounds to be controlled are benzene, 2,2,4-trimethylpentane, cresols, butylbenzene, hexane, methyl ethyl ketone, methyl tert -butyl ether, naphthalene, phenol, toluene, and mixed xy -lenes. According to EPA, the rule would cut total emissions 60%, or more than 277,000 tons annually. The rule would regulate emissions from storage tanks and leaks from pumps and valves, and would require companies to put emission controls on process vents. It also includes substantial monitoring and reporting requirements. EPA...

Predictions of metals emissions and partitioning in coal-fired combustion systems

The EPA is required by Title III of the 1990 Clean Air Act Amendments to regulate the emissions of 189 hazardous air pollutants (including trace metals) from industrial facilities. These facilities may be required to apply technology-based standards such as maximum achievable control technology (MACT) to their emitting processes. A new legislation will be implemented by specific rules and regulations promulgated by federal (EPA), state, and local agencies. Once rules are promulgated, facilities may have to conduct compliance tests and trial burns to demonstrate compliance with emission limits. The process of planning and performing such tests is formidable due to the planning time requirement and the high cost. This paper presents a computer modeling approach to predict metals behavior in coal-fired combustion systems. This treatment is not intended to be a substitute for actual compliance tests but can serve as a guide to help planners, engineers, and facility owners/operators predict the levels of metals emissions from their facilities, and to gain an insight into the impact of operating conditions on metals behavior. To test the predictive applicability of the modeling approach, predictions of the overall partitioning of metals in a pulverized bituminous coal-fired combustor were compared to measured data from full-scale facilities in the Netherlands. In general, the comparison between predicted and measured values is favorable. This indicates that using the modeling approach described in this paper can be effective in planning tests, optimizing operating conditions, and determining the effectiveness of air pollution control equipment prior to conducting actual compliance tests.

Technological change under residual risk regulation: The case of coke ovens in the U.S. steel industry

An engineering-economic model is used within a dynamic setting to determine the least cost mix of investment and import activities as the U.S. steel industry faces successively tighter controls on coke oven emissions over the next 10 years. In response to Maximum Achievable Control Technology (MACT) standards proposed for 1995, U.S. steel producers would likely export their toxic pollution by importing 6 million tons of coke per year. About 4 million tons of coke oven capacity is retrofit and about 1 million tons of annual coke consumption is replaced by new iron technologies, such as Corex. The Lowest Achievable Emission Rate (LAER) standards proposed for 1998 roughly double the coke oven retirements estimated to occur under MACT. Coke imports also are substantial but are no higher than under MACT because the additional time allows the industry to invest in more coke-saving blast furnaces and in new less toxic coke-making technologies, such as the Jewell process. The LAER standards in conjunction with higher capital costs, however, force coke imports to more than 8 million tons per year and sharply increase imports of semi-finished steel. Such a situation could exacerbate existing disputes on international steel trade.

Overview of the U.S. Environmental Protection Agency's Hazardous Air Pollutant Early Reduction Program.

Under provision of the Clean Air Act Amendments of 1990 Title III, the EPA has proposed a regulation (Early Reduction Program) to allow a six-year compliance extension from Maximum Achievable Control Technology (MACT) standards for sources that voluntarily reduce emissions of Hazardous Air Pollutants (HAPs) by 90 percent or more (95 percent or more for particulates) from a base year of 1987 or later. The emission reduction must be made before the applicable MACT standard is proposed for the source category or be subject to an enforceable commitment to achieve the reduction by January 1, 1994 for sources subject to MACT standards prior to 1994. The primary purpose of this program is to encourage reduction of HAPs emissions sooner than otherwise required. Industry would be allowed additional time in evaluating emission reduction options and developing more cost-effective compliance strategies, although, under strict guidelines to ensure actual, significant and verifiable emission reductions occur.