Two major new Waste-To-Energy (WTE) Projects have received Air Construction Permits under the Prevention of Significant Deterioration (PSD) program during the past two years and a third is scheduled to receive its permit prior to NAWTEC 20. These new facilities are being required to operate with significantly lower emissions of nitrogen oxides (NO x ) and other major air pollutants than similar existing US facilities. This paper will explore the permitting process on these three projects and the divergent approaches being taken by the applicants to meet the stringent emission requirements imposed by the PSD permits. The Palm Beach County (Florida) Renewable Energy Facility No. 2 (PBREF No. 2) will be a three unit, 3,000 ton per day (tpd) mass burn facility which will utilize Selective Catalytic Reduction (SCR) systems similar to that used in many recent European WTE facilities for NO x control. The Fairfield (Maryland) Renewable Energy (Fairfield) and Aercibo (Puerto Rico) Renewable Energy (Aercibo) Projects are each two unit, 2,106 tpd Refuse Derived Fuel (RDF) facilities which will utilize regenerative SCR (RSCR ® ) systems. This will be the first time RSCR ® has been used in a WTE application. All three permits require achievement of a NO x emission rate of 45 parts per million by volume at 7% O 2 dry basis (ppmvd). PBREF No. 2 and Fairfield received PSD permits from delegated state programs prior to the new Greenhouse Gas (GHG) and condensable PM 2.5 permitting rules going into effect at the beginning of 2011. Aercibo is being permitted by United States Environmental Protection Agency (EPA) Region II and will reflect new GHG and condensable PM 2.5 permitting rules. This paper discusses the approach to the Best Available Control Technology (BACT) and Lowest Achievement Emission Rate (LAER) determinations and differences in final permit requirements.

The world’s bleak economic outlook in the second decade of the 21st Century has placed a burden on the world’s attempts to promote a more sustainable system of energy generation. Increasingly, the cost of regulatory programs designed to protect the environment and foster a lower carbon economy has become of significant concern. A recent example is the retraction of the U.S. EPA’s revision of the Ozone National Ambient Air Quality Standards, cited as part of a larger effort aimed at “reducing regulatory burdens and regulatory uncertainty, particularly as our economy continues to recover”, in a statement issued recently by the White House.

Nitrogen Oxide (NO x ) emissions of new Energy-from-Waste (EfW) facilities, especially in ozone non-attainment zones, are coming under increased scrutiny by permitting agencies in the US as new EfW projects are permitted. While the EPA national technology based limits for EfW plants under the New Source Performance Standards are still at 150 ppmdv at 7% O 2 , many permitting authorities are requiring substantially lower limits for new EfW plants in their states or air quality regions under EPA’s New Source Review/Prevention of Significant Deterioration air quality permitting program. This trend is directly related to the question, how the Lowest Achievable Emission Rate (LAER) and Best Available Control Technology (BACT) limits for NO x in EfW plants should be defined in ozone nonattainment and attainment areas respectively. Since lower NOx limits increase the cost of EfW as a sustainable waste management method, too stringent emission limits may have the adverse effect that more waste is landfilled due to the economic competition between these waste management methods which will actually lead to higher overall emissions and lower sustainability. Like other technology suppliers, Hitachi Zosen Inova (HZI, earlier AE&E Inova), a worldwide leader in EfW technology, has used various NO x control options. Apart from standard SNCR systems which can safely meet the EPA NSPS limits, there is DyNOR™, the advanced SNCR-based technology which can safely reach values below 100 ppmdv at 7% O 2 , and the SCR (Selective Catalytic Reduction) technology, which can reach values down to far below 50 ppmdv at 7% O 2 . However, once a certain emission limit is determined, the question is how this limit can be safely and continuously achieved with the lowest possible cost per ton of waste treated.

Most ash generated by waste-to-energy (WTE) facilities in the U.S. is landfilled. Studies undertaken in the late 1980’s and early 1990’s indicated no significant environmental concerns associated with ash landfilling. However, in 2001, policy-makers at the Massachusetts Department of Environmental Protection (MA DEP) became concerned that the “cumulative” impacts of landfills, including ash landfills, might pose a risk to human health. To address this concern, we performed an in-depth assessment of impacts to air quality, and theoretical risks to health, from fugitive emissions associated with an ash landfill. Nine sources of fugitive ash emissions were modeled using methods that coupled detailed information about the site operations, ash properties, and meteorological conditions on an hour-by-hour basis. The results of these assessments, combined with ambient air data collected by others, demonstrated that the impacts from fugitive emissions of the ash were no more than negligible. Accordingly, in 2006, MA DEP revised its policy, exempting ash disposal landfills from the requirement to demonstrate no significant impact, effectively granting presumptive certainty to ash landfills that employ best management practices. Detailed analyses such as described herein, combined with robust data sets, can form the basis of more efficient regulatory policies.

Solid waste incinerators emit air pollutants such as SO 2 , HCl, and mercury. Dry sorbent injection of sodium sorbents has emerged as an important SO 2 , HCl, and mercury mitigation technology due to its (a) low capital cost; (b) small installation foot print; (c) ease of operation; and (d) flexibility to fuel changes. In a dry sorbent injection system, trona or sodium bicarbonate is injected directly into hot flue gas. After injection, the sorbent is calcined into porous sodium carbonate that reacts with acid gases (SO 2 , HCl and SO 3 ). This technology is able to achieve high removal rates for HCl (>99%) and SO 2 (>90%), and has been implemented at many waste incinerators in Europe and coal-fired power plants in the United States. With the promulgation of MACT rules, this technology will be a low-cost and easy-to-use option for waste-to-energy boiler owners.

Thermal technologies, such as gasification, pyrolysis, waste-to-energy (WTE), and advanced thermal recycling (second generation WTE with the most advanced air emission control system), can be employed to recover energy from municipal solid waste (MSW), reduce the volume of material to be landfilled, and lessen the potential emission of methane. Methane is a potent greenhouse gas and a major component of landfill gas. All operating WTE facilities in the United States have been subjected to strict environmental regulations since the passage of the Clean Air Act Amendments in 1990. As a result, U.S. WTE facilities now meet or exceed stringent local air quality standards, including those imposed by the South Coast Air Quality Management District (SCAQMD) in Southern California. The United States Environmental Protection Agency (EPA) recognizes the important role of WTE in the integrated solid waste management and ranks combustion higher than landfilling in its solid waste management hierarchy. In addition to upstream source reduction and recycling, downstream thermal treatment of the residual MSW (conducted in controlled environment) can effectively recover energy and further reduce waste volume. Despite all the advantages and environmental benefits of thermal technologies, its utilization for treating MSW in California still faces many challenges. These include negative public perceptions, economical disadvantages, local marketability of by-products, and disposal options for residuals. This paper discusses the need to include energy recovery in the integrated MSW management in California and the challenges encountered by many local jurisdictions.

Renewed interest in waste-to-energy (WTE) has spurred a number of plans for facility expansions, retrofits and in several cases, new facilities. Complex federal and state regulations governing stationary air pollution sources challenge projects to develop and implement a compliance strategy that meets current and emerging regulatory requirements and which consists of commercially available and technically feasible control technologies, while managing the financial viability of the project. Past experience in the WTE industry is indicative of current challenges, and the deliberate development of WTE in the United States over the last 15 years now creates challenges when technologies developed and implemented elsewhere must be considered. One example is control of nitrogen oxides. Individual projects are subject to regulatory requirements differently, with net emissions increases, location and other attributes establishing the basis for regulatory compliance. This paper will discuss the complex New Source Review permitting requirements that typically apply to WTE projects, review commercially available air pollution control technologies, and discuss, through the use of a case study, the decision-making process used to develop the air pollution control strategy for the York County Resource Recovery Center expansion, one recent development of new WTE capacity in the United States.

The incorporation of municipal solid waste combustor (MWC) ash into bituminous pavements has been investigated in the United States since the middle 1970s. Thus far, most, if not all of these projects, have attempted to answer the questions: Is it safe? Is it feasible? Or does it provide an acceptable product? Polk County Solid Waste located in Northwest Minnesota has now completed three Demonstration Research Projects (DRP) utilizing ash from its municipal solid waste combustor as a partial replacement of aggregate in asphalt road paving projects. The results of these projects show no negative environmental or worker safety issues, and demonstrate improved structural performance and greater flexibility from the ash-amended asphalt as compared to conventional asphalt. Polk County has submitted an application to the Minnesota Pollution Control Agency (MPCA) to obtain a Case-Specific Beneficial Use Determination (CSBUD), which would allow for continued use of ash in road paving projects without prior MPCA approval. However, concerns from the MPCA Air Quality Division regarding a slight increase in mercury emissions during ash amended asphalt production has resulted in a delay in receiving the CSBUD. Polk County decided to take a different approach. In January 2008, Polk submitted and received approval for their fourth ash utilization DRP. This DRP differs from the first three in that the ash will be used as a component in the Class 5 gravel materials to be used for a Polk County Highway Department road rebuilding project. The project involves a 7.5 mile section of County State Aid Highway (CSAH) 41, which conveniently is located about 10 miles south of the Polk County Landfill, where the ash is stored. The CSAH 41 project includes the complete rebuilding and widening of an existing 7.5 mile paved road section. Ash amended Class 5 gravel would be used in the base course under the asphalt paving, and also in the widening and shouldering sections of the road. The top 2 inches of the widening and shouldering areas would be covered with virgin Class 5 and top soil, so that all ash amended materials would be encapsulated. This has been the procedure followed in previous projects. No ash will be used in the asphalt mix for this project. This paper discusses production, cost, performance and environmental issues associated with this 2008 demonstration research project.

The COUNCIL OF THE EUROPEAN UNION has enacted laws to improve the quality of the ambient air: The “COUNCIL DIRECTIVE 1999/30/EC of 22 April 1999 relating to limit values for sulphur dioxide, nitrogen dioxide and oxides of nitrogen, particulate matter and lead in ambient air” and the “DIRECTIVE 2008/50/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 21 May 2008 on ambient air quality and cleaner air for Europe”. The Member States had to bring into force the laws, regulations and administrative provisions necessary to comply with these Directives. These Directives are raising the expectations on the reduction of fine particulate matter on the potential emitters, mainly public traffic, industry and waste-to-energy (WtE) plants. Although there is currently no European regulation on stack emissions of fine particulate matter, local regulatory authorities have tightened the emission limits of total particulate matter. For example, quite a number of Italian WtE plants are expected to meet dust emission levels of less than 2 mg/m 3 . In order to assure compliance strong efforts and large investments have been made to optimize the efficiency of their APC system. Different dust filtration technologies will be compared and the filtration principles of depth filtration and surface filtration will be detailed. A comparison of an experimental study and the practical performance of the different technologies are discussed. Special focus will be given to the development and application of High Efficiency Membrane Filter Laminates for retention of fine particulate matter. These filter materials consist of micro-porous expanded PolyTetraFluoroEthylene (ePTFE) membranes laminated onto suitable backing materials, retention rates of > 99.99% of PM 2.5 have been achieved. A number of large European WtE plants have already completed their APC upgrades by using the High Efficiency Membrane Filter Laminates. Some of them are on operation for a couple of years, performance reviews will be detailed.

The dominant waste-to-energy technology is combustion of “as-received” municipal solid wastes (MSW) on a moving grate. By far, the largest cost item in the operation of such plants is the repayment of the initial capital investment of $600 to $750 per annual metric ton of capacity which results in capital charges of $60–75 per ton of MSW processed. On the average, such plants generate about 650 kWh of electricity per metric ton of MSW combusted. Therefore, on the basis of 8,000 hours of operation per year (90% availability), the capital investment in WTE facilities ranges from $7,500 to $9,000 per kW of electric capacity. This number is three times higher than the present cost of installing coal-fired capacity (about $2,500 per kW). Of course, it is understood that WTE plants serve two purposes, environmental disposal of solid wastes and generation of electricity; in fact, most WTE plants would not exist if the fuel (i.e. the MSW) had to be paid for, as in the case of coal, instead of being a source of revenue, in the form of gate fees. However, the question remains as to why WTE plants are much more costly to build, per kWh of electricity generated, than coal-fired plants, even when the coal supply is lignite of calorific value close to that of MSW (about 10 MJ/kg). This study intends to examine the possible contributing causes, one by one, in the hope that the results may lead to the design of less costly WTE plants. Some of the factors to be examined are: Feed-stock handling; heat generation rate per unit volume of combustion chamber; heat transfer rate per unit area of boiler surfaces; % excess air and, therefore, volume of gas to be treated in Air Pollution per kW of electricity; differences in gas composition and high temperature corrosion in boiler that limit steam temperature and pressure and thus thermal efficiency; cost of APC (air pollution control) system because of the need to remove volatile metals and dioxin/furans from the process gas; and the handling of a relatively large amount of ash. In seeking the answers to the above questions, the study also compares the operational performance characteristics and engineering design of various existing WTE plants. This study is at its very beginning and it is presented at NAWTEC 17 in the hope of generating useful discussion that may lead to significant improvements in the design of future WTE facilities. The WTEs built in the U.S. until 1995 were designed for efficient and environmentally benign disposal of MSW, with energy recovery being a secondary consideration. There have been three principal changes since then: (a) the capital cost of WTEs, per daily ton of capacity has doubled and in some cases nearly tripled, (b) energy recovery per unit of carbon dioxide emitted has become an important consideration, and (c) the price of renewable electricity has increased appreciably. All these three factors point to the need for future WTEs to become more compact, less costly to build, and more energy-efficient. It is believed that this can be done by combining developments that have already been tested and proven individually, such as shredding of the MSW, higher combustion rate per unit surface area of the grate, oxygen enrichment, flue gas recirculation and improved mixing in the combustion chamber, superior alloys used for superheaters, and steam reheating between the high-pressure and low-pressure sections of the steam turbine. For example, oxygen enrichment is practiced at the Arnoldstein, Austria, WTE where parts of the primary air stream are enriched between 23% and 31% oxygen; steam reheating has been proven at the Waste Fired Power Plant of AEB Amsterdam where electricity production for the grid has been increased to over 800 kWh per ton MSW.

This investigation has been initiated to characterize the thermal decomposition of waste tires with Thermo-Gravimetric Analysis (TGA) in various atmospheres ranging in oxygen content; 100% N 2 , 7%, 21% (air) and 30% O 2 . Chemical analysis focusing on light hydrocarbons, substituted aromatics, and polycyclic aromatic hydrocarbon has been done qualitatively and quantitatively to understand the mechanism of thermal degradation of scrap tires and hazardous air pollutants such as PAH. The release of chemicals from scrap tires has been determined experimentally using Gas Chromatography/Mass Spectroscopy (GC/MS) coupled to TGA unit. The identities and absolute concentrations of over 50 major and minor species have been established. Significant volatile organic carbons (VOC) including substituted aromatics and PAH were observed between 300°C and 500°C. In addition, significant black carbon residual was observed in most environments except air and oxygen enhanced atmospheres and suggested not only the potential recovery of black carbon out of feedstock, but also the possibility of combined thermal treatment between combustion and gasification. These measurements supply information on the identities and levels of hazardous air pollutants, and provide useful new data for the development and validation of detailed reaction mechanisms describing their origin and fate. Finally, while high contents of VOC show significant potential to be utilized as an unconventional solid fuel, they also tend to generate hazardous pollutants.

Tremendous money is wasted due to the lack of attention to the water gauge and flue plate stiffeners, and their impact on the insulation and lagging design. The design and installation of an insulation and lagging system will depend heavily upon the flue or duct stiffener arrangement. The stiffener arrangement is determined by many factors including the water gauge of the flue or duct plate design. The stiffener pattern and size is the first thing you consider when designing an insulation and lagging system. Therefore, it is imperative to understand how the size, shape and pattern of the external stiffeners are developed. The stiffener sizing of yesterday was based on a much lower water gauge pressure and allowed the insulation to be placed between the stiffeners without having to cut-to-fit. The stiffeners being designed today are quite large and much farther apart. This is due in part to the water gauge number being used in the design calculations and because they have not considered the required insulation thickness and application. A well designed and installed insulation and lagging system will save money and energy at a rate that is essential for an efficient plant operation. This is especially true when adding a selective catalytic reduction system (SCR) or a selective non catalytic reduction system (SNCR) to the back end of a steam-generating unit. The insulation and lagging system is critical for these air pollution systems to operate correctly.

Wasatch Energy Systems owns and operates two (2) mass burn incinerators each rated at 210 tons/day in Layton, Utah. Each incinerator was equipped with a three field Electrostatic Precipitator (ESP) to control the particulate emissions. Dry sorbent (trona) was injected just upstream of the economizer to control acid gas emissions. The performance of the dry sorbent injection system was marginal. In anticipation of the upcoming EPA emission guidelines, 40 CFR Part 60, Subpart BBBB, Emission Guidelines for existing small municipal waste combustion units, Wasatch Energy Systems decided to update the existing APC systems several years ahead of the schedule. A request for proposal was released in October 1999 and eight proposals were received by the facility. AirPol Inc. of Parsippany, NJ was awarded a turnkey contract in June 2000 to add a dedicated Gas Suspension Absorber (FLS miljo Inc GSA) upstream of each existing ESP. A common lime slurry storage and preparation system, carbon storage and delivery system, ash conveying system, MCC, and control system were also provided under the contract. The new APC system was commissioned and put into service in September, 2001. Initial stack testing was conducted in October 2001 to evaluate system performance. Compliance stack testing was conducted for the Utah Division of Air Quality in November 2001. Results of testing demonstrate that particulate, metals, acid gas and dioxin/furan emissions from the retrofit facility are substantially lower than required under, now final, 40 CFR Part 60, Subpart BBBB – Class 1 Emission Limits for Existing Small Municipal Waste Combustion Units. This paper discusses the retrofit system design and performance.

This study has been initiated to quantify the release of the Polycyclic Aromatic Hydrocarbon (PAH) species from Styrene Butadiene Copolymer (SBR) during gasification. The identification and quantification has been determined experimentally using Gas Chromatography/Mass Spectroscopy (GC/MS) coupled to a Thermo-Gravimetric Analysis (TGA) unit. SBR samples were pyrolysed in a TGA unit in a N 2 atmosphere. The identities and absolute concentrations of over 32 major and minor species have been established, including a large number of aromatics, substituted aromatics, and PAHs. The light hydrocarbon species also have been determined simultaneously and identified as H 2 , C 2 H 2 , CH 4 , C 2 H 6 , and C 4 H 10 with lower concentrations of other hydrocarbon gases. Significant amounts of ethyl benzene, toluene, and styrene were observed between 330°C and 500°C. The largest PAH detected was the family of C 24 H 14 (molecular weight 302), benzo[ghi]perylene with peak concentrations reaching 0.19 ppmv. The effluent species detected suggest that formation of PAH’s occurs either through hydrocarbon addition reactions or benzene ring re-combination reactions. In addition, the chemical structure of SBR lends itself gas phase release of benzene molecules or radicals, thus facilitating the PAH production route. Preliminary calculations done using MOPAC provided some insight into the energy required to break the benzene ligand bond from the butadiene structure. The measurements supply information on the identities and levels of hazardous air pollutants, and provide useful new data for the development and validation of detailed reaction mechanisms describing their origin and fate.