Public private partnership has played a mayor role in development and successful operation of the current KMS Peel Waste-to-Energy Plant located in Peel Region, Ontario. On December 10, 1998 KMS Peel Inc. and the Region of Peel entered into an agreement to expand the waste-to-energy facility by 36,000 tonnes (one additional incineration unit). Due to expansion, new, more stringent emission limits were imposed by the latest Ontario Ministry of Environment A-7 Guideline and the Canada-Wide Standards developed by Canadian Council of Ministers of Environment. A Selective Catalytic Reduction (SCR) system with a sodium tetrasulphide injection was selected to supplement the existing dry scrubber/fabric filter air pollution control system for additional reduction in mercury, nitrogen oxides and dioxins/furans emissions. With the upgraded air pollution control technology, the facility will be able to meet the latest emission standards and, to a certain degree, any new standards that may be enforced in future years. This paper outlines a partnership model that has been successfully implemented in Ontario and has contributed to the public accepting waste-to-energy as integral part of the waste management system, ultimately resulting in facility expansion. It also describes the current facility and upgrade to the existing air pollution control system.

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.

During combustion, most of the waste’s nitrogen content is transferred to the flue gases as nitrogen oxide, NO x . The EU Waste Incineration Directive defines a maximum emission limit value for NO x of 200 mg/Nm 3 as a daily average value referred to 11% O 2 . Based on National Emission Ceilings (NEC) defined by the Gothenburg Protocol, it can be expected that the limit values for NO x in the EU will become even more stringent. In some European countries (e.g. The Netherlands, Austria, Switzerland) a lower emission limit has already been introduced. Selective Catalytic Reduction (SCR) technologies are used in many cases to achieve the above-mentioned NO x limits. However, there are drawbacks to SCR systems such as high investment cost. Operation cost is also quite high due to the energy consumption necessary for the reheating of the flue gas as well as the increased pressure loss. Innovative technologies are therefore required to make it possible to reconcile both requirements: reduced emissions and increased energy efficiency. Selective Non-Catalytic Reduction (SNCR) systems are based on the selective reaction of ammonia or urea injected into the upper furnace. In many cases SNCR technologies are limited by the ammonia slip which increases in case of more stringent NO x requirements. According to the relevant BREF document, an ammonia slip limit of 10 mg/Nm 3 is generally required at the stack. In order to achieve reduced NO x values, it is necessary to implement measures to reduce ammonia slip, by means of either a wet scrubber or a High-dust catalytic converter. EfW plants in Mainz (Germany) and Brescia (Italy) are examples of operational plants combining SNCR with such a catalytic converter type. In addition R&D activities are carried out on the development of simplified reaction mechanisms to be implemented in Computational Fluid Dynamics (CFD) codes. With these tools it will be possible to describe the interaction between turbulent mixing, radiation and chemical reaction rates. Another option to achieve low NO x values (below 100 mg/Nm 3 ) is the reduction of NO x by so-called primary measures, e.g. the Very Low NO x process (VLN), which has been developed by MARTIN jointly with its cooperation partners. The VLN process is based on a grate-based combustion system. The “VLN gas” is drawn off at the rear end of the grate and is reintroduced into the upper furnace in the vicinity of the SNCR injection positions. NO x will be reduced significantly, ensuring low NO x emission values at the stack as required, at low values for ammonia slip. The new EfW plant in Honolulu (USA) will be equipped with the VLN process. In Coburg (Germany), the VLN process will be retrofitted in an existing installation. This paper documents the potential and the limitations of different measures for NO x reduction as well as examples of recent innovative EfW plants in Europe using MARTIN technologies successfully.

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.

A greenfield Refuse Derived Fuel (RDF) facility in Alliance Ohio will process 2,400 Tons Per Day (TPD) of Municipal Solid Waste (MSW) and Construction & Demolition Debris (C&D). The Ohio EPA has issued the final air permit for the facility. There will be two equipment trains to handle the material each consisting of Riley Power’s Advanced Stoker™ boiler, Turbosorp® dry scrubber, and Regenerative Selective Catalytic Reduction (RSCR®) nitrogen oxides (NOx) control system. The key parts of the “chute to stack” equipment represent a significant advancement in technology when compared to past facilities, as demonstrated by the designation by the State of Ohio as an “Advanced Energy Project”. The Riley Advanced Stoker™ boiler has unique design features to ensure high efficiency, corrosion resistance, and fuel flexibility while at relatively low cost. The use of the Turbosorp will result in lower emissions of lead, other volatile heavy metals, and mercury than for a typical spray dryer/baghouse (SDA) system. Acid gas removal is also superior to an SDA system while utilizing less lime reagent and power. The RSCR follows the Turbosorp as a “low dust” SCR but with auxiliary energy consumption about 85% lower than a typical low dust, tail end SCR. The RSCR will reduce NOx and Carbon Monoxide (CO) emissions to low values when compared to other facilities producing energy from waste. This paper will describe the design basis for the system including fuels to be processed, steam flow and conditions, and emissions. A detailed description of the technologies will also be presented.

Babcock Power Environmental (BPE), a Babcock Power Inc. company, has developed a new, innovative, high-efficiency NO x reduction technology designed to greatly reduce the NO x emissions from waste to energy (WTE) boilers at relatively low cost. This “tail-end” system uses Selective Catalytic Reduction (SCR) to achieve the high reduction performance. Conventional SCR catalyst cannot be used in the traditional “high-dust” location, downstream of the economizer because constituents in the ash would poison the catalyst quickly, rendering it useless. Thus, the Regenerative Selective Catalytic Reduction (RSCR ® ) system is designed to operate at the end of the plant before the flue gas is discharged to the stack. The process utilizes a reactant (usually aqueous ammonia) to be added to the flue gas stream upstream of the RSCR to reduce NO x to harmless reaction products, N 2 and H 2 O. The RSCR combines the efficient heat recovery, temperature control, reactant mixing, and catalyst into a single unit and provides the maximum NO x reduction and heat recovery practical. The paper will describe the overall predicted performance of a typical WTE boiler plant using this new technology. The paper will also provide actual operating data on the RSCR, which has been retrofitted to four biomass-fired units.

The Algonquin Power Energy-From-Waste (APEFW) facility is located in the suburban Toronto, Ontario city of Brampton. It receives approximately 140,000 metric tonnes (154,000 tons) of MSW per year from the Region of Peel (Region) and approximately 10,000 metric tonnes (11,000 tons) per year of international airport waste from the area’s two international airports. The APEFW facility commenced initial operations in 1992 and included four, 91 tonne (100 ton) per day Consumat two stage incinerators with heat recovery boilers and a dual-train air pollution control (APC) system consisting of evaporative cooling towers, venturi reactors and fabric filter baghouses. The APEFW facility expanded its capacity in 2001 with the addition of a fifth 91 tonne (100 ton) per day modular incinerator and heat recovery boiler. One of the stipulations in the permitting process was that the entire expanded facility meet more stringent emission standards that included a significantly lower nitrogen oxides (NOx) emission rate. After a review of several available NOx control technologies, the APEFW facility chose to install a Selective Catalytic Reduction (SCR) system. While SCR systems are fairly common on EFW facilities in Europe, the APEFW facility is the only EFW facility in North America that currently operates with an SCR system and as such has gained valuable insight into the application and performance of this technology that is very relevant to the North American EFW industry. This paper discusses the operation and maintenance of the SCR system, compares pre- and post-SCR NOx emissions and presents capital and operating costs for the SCR including the cost per tonne of waste processed and the cost per tonne of NOx removed.

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.