Air Pollution Control Technologies Research Articles

Asia: target market for air pollution control technologies

Asia: target market for air pollution control technologies

Ion-drift reactor™ concept

This paper will focus on one of the advanced air pollution control (APC) technologies currently under development at MSE Technology Applications (MSE-TA). This technology, which has a patent pending, is an ion-drift reactor™ (IDR™). One of the applications of this reactor is to remove low-concentration fine particulate and hazardous pollutants, such as mercury vapor, products of incomplete combustion (PICs), and dioxins/furans from the air or incineration offgas. The pollutants are electrically sensitized by reagent ions by means of charge-exchange, hydrogen transfer, electron and ion attachments, hydrogen abstraction, and other reactions initiated by injection of reagent ions into the contaminated offgas or airstream. Selectively sensitized pollutant particles, clusters and molecules are then removed from the airstream by their drift in the electric field. In contrast to electrostatic precipitators and different types of other non-thermal plasma (NTP) technologies, the reagent ions are generated separately in the ion source of this new device and then injected into the contaminated offgas stream. This is thought to allow much better control over the discharge parameters and to allow much higher reaction selectivity than that of conventional NTP technologies. In comparison with conventional APC technologies, such as adsorption, heterogeneous catalysis, or absorption, an IDR™ utilizes ion-drift together with diffusion as the mechanisms of mass transfer, which reduces the reactor residence time and the differential pressure drop across the reactor in analogous conditions. These advantages are especially important for removal of mercury, other trace elements, and fine respirable particulate (PM 2.5) from the incineration offgas and air.

00/01118 Survey of aircure experience on dust control system for PRB coal

This paper will focus on one of the advanced air pollution control (APC) technologies currently under development at MSE Technology Applications (MSE-TA). This technology, which has a patent pending, is an ion-drift reactor™ (IDR™). One of the applications of this reactor is to remove low-concentration fine particulate and hazardous pollutants, such as mercury vapor, products of incomplete combustion (PICs), and dioxins/furans from the air or incineration offgas. The pollutants are electrically sensitized by reagent ions by means of charge-exchange, hydrogen transfer, electron and ion attachments, hydrogen abstraction, and other reactions initiated by injection of reagent ions into the contaminated offgas or airstream. Selectively sensitized pollutant particles, clusters and molecules are then removed from the airstream by their drift in the electric field. In contrast to electrostatic precipitators and different types of other non-thermal plasma (NTP) technologies, the reagent ions are generated separately in the ion source of this new device and then injected into the contaminated offgas stream. This is thought to allow much better control over the discharge parameters and to allow much higher reaction selectivity than that of conventional NTP technologies. In comparison with conventional APC technologies, such as adsorption, heterogeneous catalysis, or absorption, an IDR™ utilizes ion-drift together with diffusion as the mechanisms of mass transfer, which reduces the reactor residence time and the differential pressure drop across the reactor in analogous conditions. These advantages are especially important for removal of mercury, other trace elements, and fine respirable particulate (PM2.5) from the incineration offgas and air.

00/01120 Zero-emission plant on the drawing board

This paper will focus on one of the advanced air pollution control (APC) technologies currently under development at MSE Technology Applications (MSE-TA). This technology, which has a patent pending, is an ion-drift reactor™ (IDR™). One of the applications of this reactor is to remove low-concentration fine particulate and hazardous pollutants, such as mercury vapor, products of incomplete combustion (PICs), and dioxins/furans from the air or incineration offgas. The pollutants are electrically sensitized by reagent ions by means of charge-exchange, hydrogen transfer, electron and ion attachments, hydrogen abstraction, and other reactions initiated by injection of reagent ions into the contaminated offgas or airstream. Selectively sensitized pollutant particles, clusters and molecules are then removed from the airstream by their drift in the electric field. In contrast to electrostatic precipitators and different types of other non-thermal plasma (NTP) technologies, the reagent ions are generated separately in the ion source of this new device and then injected into the contaminated offgas stream. This is thought to allow much better control over the discharge parameters and to allow much higher reaction selectivity than that of conventional NTP technologies. In comparison with conventional APC technologies, such as adsorption, heterogeneous catalysis, or absorption, an IDR™ utilizes ion-drift together with diffusion as the mechanisms of mass transfer, which reduces the reactor residence time and the differential pressure drop across the reactor in analogous conditions. These advantages are especially important for removal of mercury, other trace elements, and fine respirable particulate (PM2.5) from the incineration offgas and air.

The Political and Legal Causes of Regulatory Delay in the United States: Four Case Studies of Air Pollution Permitting in the U.S. and Germany

We compare the process to obtain air pollution emission permits for automobile assembly plants in the U.S. and Germany. The project consists of four case studies in which comparisons are made with respect to the costs of obtaining air pollution permits for assembly plant shops--the part of the factory where new cars and trucks are painted. The plants are owned by the same company, use nearly identical paint application technologies and paints, and use virtually the same air pollution control technologies. Moreover, both countries are federalist in structure, with the national government setting general standards, and the states issuing and enforcing individual permits. These similarities allow us to compare the permitting processes in U.S. and Germany, and to isolate the salient political and legal differences and economic consequences. In both the United States and Germany, state air pollution agencies implement federal standards that effectively require the assembly plants to install similar pollution abatement technologies to control emissions resulting from increases in production or changes in paint composition. Nevertheless, the two countries' regulatory processes are rather different. Air pollution control laws, regulations, and plant-level permits in the U.S. are somewhat more stringent, detailed, and prescriptive than in Germany. Moreover, U.S. law provides substantially greater opportunity for public participation in agency permitting decisions, and at one U.S. plant, public participation significantly affected the regulatory outcome. For these and other reasons, the permitting processes at the U.S. plants were much slower and more conflictual than at the German plants, resulting in much longer delays in making production changes and installing new pollution controls.

Evaluation of the available air pollution control technologies for achievement of the MACT requirements in the newly implemented new source performance standards (NSPS) and emission guidelines (EG) for hospital and medical/infectious waste incinerators

After many years of research and debate, in August of 1997 the United States Environmental Protection Agency (EPA) issued New Source Performance Standards (NSPS) and Emission Guidelines (EG) for medical/infectious waste incinerators in the United States. These new emissions and operational standards establish considerably more restrictive limitations on air emissions for medical/infectious waste incinerators and will undoubtedly have a significant impact on the over 2300 hospitals presently operating an incinerator on-site. This paper will explore the options available to these facilities, and those facilities which may be considering installation of an incinerator, relative to achieving compliance with the NSPS and EG for medical/infectious waste incinerators.

The effect of nitrate on VOC removal in trickle-bed biofilters

In response to the growing concern over volatile organic compounds (VOCs), biofiltration is becoming an established economical air pollution control technology for removing VOCs from waste air streams. Current research efforts are concentrating on improving control over key parameters that affect the performance of gas phase biofilters. This study utilized diethyl ether as a substrate, nitrate as the sole nutrient nitrogen source within two co-currently operated trickle-bed biofilters, for over 200 days. The two pelletized medium biofilters were operated at a low empty bed contact time of 25 s, inlet gas flow rates of 8.64 m 3/day, nutrient liquid flow rates of 1 liter/day, and COD loading rates of 1.8 and 3.6 kg/m 3 per day, respectively. Operational parameters including contaminant concentration in the gas phase, nutrient nitrate concentration in the aqueous phase, and the frequency of biomass removal were considered. Special attention was given to the effect and the role of nitrate on VOC removal. Throughout the experiment, nitrate persisted in the liquid effluent and the ether removal efficiencies improved with increasing influent nitrate concentration, which suggest that the nitrate diffusion into the biofilms is rate determining. By increasing the concentration of oxygen in the feed to this biofilter from 21% (ambient air) to 50 and 100%, while maintaining an influent ether concentration of 133 ppmv and a feed nitrate concentration of 67 mg-N/liter, the performance of the biofilter was not significantly affected. These results suggest that nitrogen was rate limiting as a growth nutrient rather than as an electron acceptor for the respiration of ether. The results also indicated that removal of excess biomass is necessary to maintain long-term performance. However, the required frequency of biomass removal depends on operating parameters such as loading.

Industry's role in air quality improvement: Environmental management opportunities for the 21st century

AbstractMore than 200 years ago, Adam Smith, the founder of modern economics, wrote in the Wealth of Nations that “…consumption is the sole end and purpose of all production; and the interest of the producer ought to be attention to…that of the consumer.” In recent years, the rapid growth of the world economy has given Adam Smith's maxim new meaning. The age‐old desire for consumption grows unabated and increasing numbers of consumers around the world are attaching new value to the environmental quality of goods and services and expressing concern over the environmental impacts of industrialization. That concern is growing because more than 70 percent of the world's urban population live in areas where the air is seriously polluted and as many as 750,000 people—the majority in developing countries—die each year of ailments caused by air pollution.1Over the past 25 years, corporations throughout the world have made dramatic changes in the way they do business as more people come to understand how the ecological system works and how polluted air and water endanger human health. The key to increasing industry's participation in the drive for higher standards of air quality is the growing realization that effective environmental management, technological development, and technology dissemination are cost‐effective and profitable business strategies. Global competition is making firms around the world more customer‐conscious and, to the extent that consumers demand products that minimize environmental degradation and enhance the quality of their lives, businesses in every industry must respond in order to survive.2This article examines how changes in business practices, driven by a better understanding of how natural environments function, are converging to provide new opportunities for environmental management that go beyond regulatory compliance to reduce air pollution. Although sound and well‐enforced environmental regulations are an essential foundation for improving air quality, command‐and‐control systems alone are unlikely to achieve the lower levels of pollution that will be necessary to achieve sustainable development in the 21st century. In cooperation with government, businesses in every industry can play crucial roles in achieving higher standards of air quality while at the same time maintaining acceptable levels of economic growth. We explore three ways in which corporations can contribute to environmentally sustainable development: (1) by adopting proactive environmental management systems that focus on air pollution prevention; (2) by developing new technologies for air pollution control and reduction; and (3) by transferring air pollution control and prevention technologies through international trade and investment.

Modeling of acetone biofiltration process

AbstractBiofiltration has been validated as a promising alternative to other conventional air pollution control technologies [1–3]. The objective of this research was to investigate the kinetic behavior of the biofiltration process for the removal of acetone, which was used as a model compound for highly water‐soluble gas pollutants. Experiments were conducted in a laboratory‐scale biofilter with a mixture of sieved compost and inert porous particles as the filter material. It was found that the elimination capacity of this biofilter could reach up to a high value of 80 g/(m3hr).A mathematical model was developed by taking into account diffusion and biodegradation of acetone and diffusion of oxygen in the biofilm, mass transfer resistance in the gas film, and flow pattern of the bulk gas phase. The simulated results obtained from the proposed model indicated that mass transfer resistance in the gas phase was negligible for this biofiltration process. Analysis of the relative importance of individual rate steps indicated that the overall acetone removal process was primarily limited by the oxygen diffusion rate. Moreover, the gas phase acetone concentration profile along the biofilter and the elimination capacity predicted by the proposed model agreed well with the experimental results.

Biofiltration: A promising and cost‐effective control technology for Odors, VOCs and air toxics

Biofiltration, a relatively recent air pollution control technology, has been identified as a promising method of odor, VOC and air toxic removal form waste‐gas streams because of low capital and operating costs, low energy requirements and an absence of residual products requiring further treatment or disposal. Biofiltration units are microbial systems incorporating microorganisms grown on a porous solid media like compost, peat, soil or mixture of these materials. The filter media and the microbial culture are surrounded by a thin film of water called biofilm. Waste‐gases containing biodegradable VOCs and inorganic air toxics are vented through this biologically active material, where soluble contaminants partition into the liquid film and are biodegraded by the resident microorganisms in the biofilm. The technology has been successfully applied to a wide range of industrial and public sector sources for the abatement of odors, VOCs and air toxics, with an elimination efficiency of more than 90%. Owing to its economic advantage over the conventional air pollution control methods coupled with environmental benefits like low energy requirements and the avoidance of cross‐media transfer of pollutants, biofiltration is becoming more popular and practical in meeting the statutory emission regulations. The study presents an overview of the historical development and present status of biofiltration; summarizes its basic requirements, engineering fundamentals, operating principles, applicability, cost‐effectiveness and potential failures.

Biofiltration: Fundamentals, Design and Operations Principles, and Applications

Biofiltration is a biological air pollution control technology for volatile organic compounds (VOCs). This paper summarizes the fundamentals, design and operation, and application of the process. Biofiltration has been demonstrated to be an effective technology for VOCs from many industries. Large and full-scale systems are in use in Europe and the United States. With proper design and operation, VOC removal efficiencies of 95–99% have been achieved. Important parameters for design and performance are empty-bed contact time, gas surface loading, mass loading, elimination capacity, and removal efficiency. Key design and operation factors include chemical and media properties, moisture, pH, temperature, nutrient availability, gas pretreatment, and variations in loading.

Legislation-induced bubble markets: Driving forces of air pollution control technology in the field of waste incineration

Only recently has discussion started about the process whereby markets come into existence. Environmental problems are being increasingly addressed, which in turn creates new environmental markets. The concept of the market is presented in the perspective of microeconomic theory, industrial organization, and the life cycle concept. It is suggested that in these theories the existence of markets is taken for granted and is not questioned. On the basis of an exploratory field study it is argued here that in some areas environmental legislation is the major driving force behind the emergence of markets and the concept of legislation-induced bubble markets is introduced. The main contribution of this article is to indicate a new research area, namely the creation of markets.

The effect of nitrate on VOC removal in trickle bed biofilters

Biofiltration is becoming an established economical air pollution control technology for removing volatile organic compounds (VOCs) from waste air streams. This study utilizes diethyl ether as a VOC substrate and nitrate as a nitrogen nutrient source to investigate the effect of nitrate on VOC removal. Two trickle bed biofilters with pelletized media were operated co-currently at ether loading rates of 1.78 and 3.56 kg COD/m3·day respectively, with a low empty bed retention time of 25 seconds, inlet gas flow rate of 8.64 m3/day and nutrient liquid flow rate of 1 1/day. The ether removal efficiencies improved from 72% to over 99% with increasing influent nitrate concentration from 66.7 to 266 mg NO3-N/l in the higher loaded column. Throughout the experiment, nitrate persisted in the liquid effluent. The lower ether removal at low influent nitrate concentrations was not due to nitrogen shortage, which suggests that the nitrate diffusion in the biofilms is rate determining. The higher COD:N consumption ratio in the biofilter with higher ether loading also indicates that ether removal may benefit from the utilization of nitrate as an alternative electron accepter in the deeper layers of the biofilm where the oxygen may be limited.

Overview of municipal waste incineration industry in west Europe (based on the German experience)

This paper presents an overview of the current status of the waste-to-energy activities in the west European countries, outlining the demand for municipal waste incineration and the development in the design of the combustion system as well as in the air pollution control system. Trend setter in the technical development over the last 10 years have been the emissions regulations for waste incinerators. As an example the Dutch, Austrian, Swiss, German and EC-legislation is compared with the current state-of-the-art flue gas treatment technology and its achievable emission values. The boost of new technologies was mainly created by the dramatic tightening of these emissions legislation. The second part of the paper details the status of air pollution control technologies currently being used. Various four to five stage flue gas cleaning processes, including the recovery of marketable products from the residuals, are covered. Hence not only the minimization of stack emissions is politically pursued. The requirement of resource recovery from residuals has become more and more a major criteria for the design of flue gas treatment processes. This paper explores the process technologies used in achieving this goal as well as giving an outlook on novel concepts aiming for even higher rates of recovery and better quality products. The paper concludes with a listing of the major technology vendors and with some economical/ecological aspects of waste incineration plants equipped with modern combustion and air pollution control technology.

Mercury control technologies for MWC's: The unanswered questions

It is now clear that stricter control of mercury emissions from municipal waste combustors (MWCs) and possibly medical waste incinerators (MWIs) at both the state and federal level is imminent or certain. While some facilities may meet these new standards without additional controls (e.g. refuse derived fuel (RDF) combustors), most will not. This paper will look at the available air pollution control (APC) technologies that lend themselves to retrofit for mercury capture and will suggest that questions remain as to effectivity, interference with other APC devices, and environmental impact. Regulatory considerations are reviewed and research priorities will be suggested.

Control of dioxin, furan, and mercury emissions from municipal waste combustors

There is a significant public and scientific concern over the potential risks of air pollution emissions from municipal waste combustors (MWCs). The primary pollutants of concern are polychlorinated dibenzo- p-dioxins and dibenzofurans ( PCDDs PCDFs ), and mercury (Hg). Depending on the composition of the waste and the technologies used, PCDDs PCDFs emissions may range from less than 1.0 to more than 20 000 ng/dscm. Hg concentrations in MWC flue gas may range from less than 200 to more than 1000 μg/dscm. Trace organic emissions are dependent on the combustion and flue gas cleaning technologies employed and the conditions at which they are operated. Good combustion practice and dry scrubbing techniques employing fabric filter (FF) bag houses can be used to reduce average PCDDs PCDFs emissions to less than 20 ng/dscm. Dry scrubbers in combination with electrostatic precipitators (ESPs) are less effective, resulting in typical PCDDs PCDFs emissions of less than 75 ng/dscm. Powdered activated carbon can be injected into the flue gas to reduce Hg emissions from spray dryer PCDDs PCDFs and PCDDs PCDFs systems to less than 0.08 mg/dscm. It can also be used to improve PCDDs PCDFs capture in these systems. This article provides an overview of MWC air pollution control technologies and applicable Federal air emission control requirements. Knowledge concerning PCDDs PCDFs formation is summarized, and data are provided on the performance of combustion and flue gas cleaning techniques used to control PCDDs PCDFs emissions. The fundamental Hg properties which affect capture in flue gas cleaning equipment are discussed, and the results of carbon injection control tests are summarized.

The effect of nitrate on voc removal in trickle bed biofilters

Biofiltration is becoming an established economical air pollution control technology for removing volatile organic compounds (VOCs) from waste air streams. This study utilizes diethyl ether as a VOC substrate and nitrate as a nitrogen nutrient source to investigate the effect of nitrate on VOC removal. Two trickle bed biofilters with pelletized media were operated co-currently at ether loading rates of 1.78 and 3.56 kg COD/m3·day respectively, with a low empty bed retention time of 25 seconds, inlet gas flow rate of 8.64 m3/day and nutrient liquid flow rate of 1 1/day. The ether removal efficiencies improved from 72% to over 99% with increasing influent nitrate concentration from 66.7 to 266 mg NO3−N/l in the higher loaded column. Throughout the experiment, nitrate persisted in the liquid effluent. The lower ether removal at low influent nitrate concentrations was not due to nitrogen shortage, which suggests that the nitrate diffusion in the biofilms is rate determining. The higher COD:N consumption ratio in the biofilter with higher ether loading also indicates that ether removal may benefit from the utilization of nitrate as an alternative electron accepter in the deeper layers of the biofilm where the oxygen may be limited.

Dynamics of Toluene Degradation in Biofilters

Biodegradation processes have been validated as a promising alternative to other conventional air pollution control technologies. The objective of this research was to systematically investigate the transient behavior of shut down and restart-up operation and shock loading of the biofilter. Experiments were conducted in three laboratory-scale biofilters with mixtures of chaff/compost, D.E.(diatomaceous earth)/compost, and GAC(granular activated carbon)/compost, respectively as the filter materials. Toluene was used as the gas pollutant in this study. The response of each biofilter to shock loading was studied by abruptly changing the concentration or flow rate of the inlet gas. For each transient operation, toluene concentration was continuously measured until a new steady state was achieved. The results indicated that the biofilters responded effectively to the shut down and restart-up operation and shock loading of toluene concentration or gas flow rate. Moreover, the highly adsorptive GAC could improve the biofilter performance, especially for the treatment of less water soluble compounds such as toluene. Therefore, the GAC/compost biofilter had the highest maximum elimination capacity of 97 (g hr−1 m−3).

Environmental science and technology handbook

This book bridges the gap between understanding environmental science and technology and complying with today's regulations. Clearly written in understandable, everyday English, the Environmental Science and Technology Handbook provides easy access to a wealth of information.Written by representatives from five nationally known environmental engineering firms, this handbook brings together in one source everything you need to know about Geology and Groundwater Hydrology; Air Quality; Human Health Risk Assessment; Ecological Risk Assessment; Environmental Chemistry and Analysis of Regulated Compounds; Environmental Processes; Pollution Prevention Through Total Quality Management; Air Pollution Control Technologies; Ground-water Pollution Control Technologies; Solid and Hazardous Waste Treatment and Disposal Technologies; Underground and Aboveground Storage Tank Technologies; plus an index.

Engineered Biofilter for Removing Organic Contaminants in Air

Biof iitration is an established economical air pollution control technology for removing organic contaminants in air. Existing filters using natural media, such as peat and compost, were demonstrated in the field for degrading up to several thousand ppm of contaminants. An engineered biofilter using synthetic media, such as activated carbon, has been developed that shows improvements in removal efficiency, biodegradation and space requirements over the existing filters. This carbon filter has been operated for >11 months in a bench-top unit, accomplishing ≥90 percent removal efficiency consistently in a stream containing 10 to 20 ppm of toluene. The mass transfer zone remained stationary and extremely short (1 to 4 seconds of empty bed contact time) during the entire operating period. Compared with existing filters, this engineered filter showed 40 to 80 times greater biodegradation efficiency under the selected conditions, resulting in a decreased space requirement and other advantages in equipment sizi...