Energy-from-Waste plants using grate-based systems have gained world-wide acceptance as the preferred method for the sustainable treatment of waste. Key factors are not only the reduction of waste volume and mass and the destruction or separation of pollutants but also the efficient production and use of energy (electricity, district heating/cooling, process steam), compliant disposal and the recovery of resources from combustion residues (e.g. metals, rare earths). International requirements relating to energy efficiency and materials recovery by means of thermo-recycling in Energy-from-Waste plants call for the continuing development and optimization of existing technologies and concepts. The technologies and processes for the recovery of reusable materials from dry-discharged bottom ash and from filter ash point to the key role that Energy-from-Waste plants are able to play in the efficient conservation of resources. It is primarily thermal treatment with dry discharge and subsequent processing of the bottom ash fractions that enables Energy-from-Waste plants to justify their status as universal recyclers. In addition to recovery of the energy inherent in the waste, the treatment of dry-discharged bottom ash is an important contribution to compliance with raw material and climate policies and to the promotion of closing the material cycle in general. Furthermore, dry bottom ash discharge represents a further step towards waste-free operation and “after-care-free” landfills. This paper documents the potential of Energy-from-Waste plants for the recovery of resources and provides examples of recent developments and large-scale implementations of innovative recovery technologies in Europe.

The past few years have produced significant variations in the U.S. economic climate. In turn, the revenues from the extraction and sale of both ferrous and non-ferrous metals from WTE plants have experienced wildly positive/negative swings in value. The revenue from sales of these metals and the capital costs for the process installation directly impacts financial payback, and answers the simple question: “should we do this project?” Some key criteria will be discussed: source reduction and curbside recycling and their impact on metals yield (projected vs. actual), plant size and “economy of scale”, and operating and maintenance costs. This paper will review six recent and planned metals recovery projects in the U.S. Technologies and scopes of work include simple addition of metals recovery equipment, complete systems and buildings at existing facilities, and planned systems and buildings at new facilities. The paper will summarize the criteria for metals revenue and project costs, which determine whether the project is a “Go” or a “No Go”.

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.

The Mojave Desert and Mountain Recycling Authority is a California Joint Powers Authority (the JPA), consisting of nine communities in California’s San Bernardino County high desert and mountain region. In August 2008 the JPA contracted with Gershman, Brickner & Bratton, Inc. (GBB) to prepare the Victor Valley Resource Management Strategy (Resource Management Strategy). Working with RRT Design and Construction, Inc. (RRT), GBB prepared a coordinated forward-looking strategy to guide the JPA’s future program and facilities decisions. The Resource Management Strategy focused on the Town of Apple Valley, population 70,092, and the City of Victorville, population 107,408, the two largest JPA member communities, which have a combined total of more than 130,000 tons per year of material entering the JPA’s recycling system and the Victorville Landfill. The Resource Management Strategy is underpinned by a characterization of waste loads delivered to the Victorville Landfill. A visual characterization was carried out by RRT in September/October 2008. RRT engineers identified proportions of materials recoverable for recycling and composting among all loads collected from residential and non-residential generators for a full week, nearly 300 loads total. The JPA financed and manages the operations contract for the highly automated Victor Valley Material Recovery Facility (MRF). The MRF today receives and processes an average of 130 tons per day (tpd), five days per week, of single stream paper and containers and recyclable-rich commercial waste loads. The waste characterization indicated that as much as 80 percent of loads of residential and commercial waste currently landfilled could be processed for recycling and composting in a combination manual and automated sorting facility. Residue from the MRF, which is predominated by paper, would provide potential feedstock for an energy recovery project; however, the JPA has two strategies regarding process residue. The first strategy is to reduce residue rates from existing deliveries, to optimize MRF operations. An assessment of the MRF conducted by RRT indicated that residue rates could be reduced, although this material would continue to be rich in combustible materials. The second strategy is to increase recovery for recycling by expanding the recyclable-rich and organics-dense waste load deliveries to the MRF and/or a composting facility. The Resource Management Strategy provided a conceptual design and cost that identified projected capital and operations costs that would be incurred to expand the MRF processing system for the program expansion. Based on the waste composition analysis, residue from a proposed system was estimated. This residue also would be rich in combustible materials. The December 2008 California Scoping Plan is the roadmap for statewide greenhouse gas emission reduction efforts. The Scoping Plan specifically calls out mandatory commercial recycling, expanded organics composting (particularly food residue), and inclusion of anaerobic digestion as renewable energy. The Resource Management Strategy sets the stage for JPA programs to address Scoping Plan mandates and priorities. California Public Resources Code Section 40051(b) requires that communities: Maximize the use of all feasible source reduction, recycling, and composting options in order to reduce the amount of solid waste that must be disposed of by transformation and land disposal. For wastes that cannot feasibly be reduced at their source, recycled, or composted, the local agency may use environmentally safe transformation or environmentally safe land disposal, or both of those practices. Moreover, Section 41783(b) only allows transformation diversion credit (10 percent of the 50 percent required) if: The transformation project uses front-end methods or programs to remove all recyclable materials from the waste stream prior to transformation to the maximum extent feasible. Finally, prior to permitting a new transformation facility the California Integrated Waste Management Board is governed by Section 41783(d), which requires that CIWMB: “Hold a public hearing in the city, county, or regional agency jurisdiction within which the transformation project is proposed, and, after the public hearing, the board makes both of the following findings, based upon substantial evidence on the record: (1) The city, county, or regional agency is, and will continue to be, effectively implementing all feasible source reduction, recycling, and composting measures. (2) The transformation project will not adversely affect public health and safety or the environment.” The Resource Management Strategy assessed two cement manufacturers located in the high desert region for their potential to replace coal fuel with residue from the MRF and potentially from other waste quantities generated in the region. Cement kilns are large consumers of fossil fuels, operate on a continuous basis, and collectively are California’s largest source of greenhouse gas emissions. The Resource Management Strategy also identified further processing requirements for size reduction and screening to remove non-combustible materials and produce a feasible refuse derived fuel (RDF). A conceptual design system to process residue and supply RDF to a cement kiln was developed, as were estimated capital and operating costs to implement the RDF production system. The Resource Management Strategy addressed the PRC requirement that “all feasible source reduction, recycling and composting measures” are implemented prior to approving any new “transformation” facility. This planning effort also provided a basis for greenhouse gas reduction analysis, consistent with statewide initiatives to reduce landfill disposal. This paper will report on the results of this planning and the decisions made by the JPA, brought current to the time of the conference.

The EPA has developed the Waste Reduction Model (WARM) to help solid waste managers estimate greenhouse gas (GHG) emission reductions from several different waste management practices. This model is useful for high level analysis but breaks down when applied to specific local systems. This paper will discuss new work currently being done by HDR to provide more reliable analysis of local conditions. This capability is of growing importance given the emergence of national carbon regulations which will require solid waste managers to develop greenhouse gas reduction strategies for their local systems.

In December 2007 the United Nations Framework Convention on Climate Change (UNFCCC) took place in Bali. It was based on the IPCC report no. 4 presented in Barcelona on November 2007. The messages are briefly: • Warming of the climate system is unequivocal; • Global greenhouse gas (GHG) emissions due to human activities have grown since pre-industrial times; • Continued GHG emissions at or above current rates would cause further warming and induce many changes in the global climate system during the 21 st century that would very likely be larger than those observed during the 20 th century; • Key mitigation technologies in the waste sector: Landfill Gas (LFG) methane recovery; waste incineration with energy recovery; composting of organic waste; controlled waste water treatment; recycling and waste minimisation; biocovers and biofilters to optimise methane oxidation. The above by the IPCC proposed mitigation technologies for the waste sector can be categorized regarding specific waste treatment scenarios and their efficiency expressed in kg CO 2 equivalent emitted per ton of waste. • Landfill w/o LFG recovery 1850 kg CO 2 -eq; • Landfill with LFG recovery 250–775 kg CO 2 -eq; • Energy-from-Waste plant −1000..−100 kg CO 2 -eq. With a population of little over 300 million people and a per capita municipal waste generation rate of 760 kg/person.year, the total waste generated in the USA is about 230 million Mg/year (OECD). With the treatment scenarios discussed above, the following can be stated: • If all wastes were landfilled waste disposal would correspond to 425 million tons of CO 2 equivalents. • If all wastes were incinerated in Energy-from-Waste (EfW) plants, the emissions could be reduced by about 500 million tons of CO 2 equivalents (about 9% of today’s US CO 2 output) and make the waste management sector a GHG emissions sink. • The total electricity generated from EfW plants could be as high as 15,000 MW replacing about 50 standard 300 MW power plant units. To an average US 4 person household about 3 t/year of municipal solid wastes can be allocated, corresponding to an annual difference between landfilling without LFG recovery and EfW treatment of about 6.9 Mg CO 2 -eq /year. If this household wanted to achieve the same reduction of CO 2 equivalent emissions by other means than having these wastes burnt in a modern EfW plant, they have the following options: • Remove one automobile from use (EPA: 6.0 Mg CO 2 -eq /year); • Cut household electricity consumption by 80% (EIA: 7.8 Mg CO 2 -eq /year). The European parliament commission has proposed to reduce CO 2 emissions in Europe to 20–30% below 1990 levels. In comparison with Europe, annual GHG emissions (CO 2 -eq/person year) in the U.S. today are on a level about double that of the Europe. In order to achieve a similar reduction in the U.S., significant efforts have to be done on all energy fronts. Energy-from-Waste (EfW) is one of them, which at the same time solves a space and pollution problem and does not leave these issues to future generations.

Mercury emissions from waste-to-energy facilities have been a source of public concern for more than ten years following release in the early 1990s of the EPA’s inventory of anthropogenic sources of mercury that listed MWCs as a significant source of mercury air emissions. Since 1990, source reduction, product reformulation, and increasingly effective battery recycling programs reduced mercury in trash by about 90%, according to the EPA. Pollution control equipment on waste-to-energy plants thereafter remove greater than 90% of the remaining mercury in the waste stream that is used as a fuel to generate power. The use of mercury by U.S. manufacturers will decline even further due to the virtual elimination of mercury from alkaline batteries and aggressive recycling and product substitution at hospitals, homes, and businesses. The Clean Air Act regulations promulgated in 1995 under the Maximum Available Control Technology standards have ensured that mercury emissions from waste-to-energy plants nationwide represent less than 3% of the U.S. inventory of man-made mercury sources, according to EPA, (or less than 1% of mercury emissions from all sources). Furthermore, health risk assessments completed over the past several years for new and existing waste-to-energy plants consistently reveal that the levels of mercury emissions result in exposures which are 100 times less than the threshold health effects standard established by federal and state regulatory agencies. Nonetheless, certain environmentalists and critics claim that the significant reduction in mercury air emissions has resulted in a transformation of the metal into the ash. In other words, the questions posed is whether what is not now going up the stack is instead finding its way into the ash. This paper answers that question with a resounding “no.” Based on an analysis of test data, mercury in MWC ash has not increased despite a greater than 90% reduction in mercury emissions.

This panel session reviews a topic of long-standing interest and importance to the municipal waste combustion industry; how can some or all of the ten percent (10%) by volume of incoming material that remains after municipal solid waste is combusted be productively reused? This panel will address various reuse related topics, including but not limited to the following: • Pinellas County, Florida hosts a regional program where recovered ferrous metals from municipal waste combustors are shredded and recycled; an overview of experiences, economics, and logistics will be presented. • The Pennsylvania Department of Environmental Protection (PADEP) will discuss the technical and regulatory background behind a September 2003 Consent Decree entered with American Ash Recycling for removal of residual materials in York County, Pennsylvania. • The City of Tampa has short-listed two (2) companies for what promises to be a precedent-setting ash reuse program; a status report will be given. • SUNY Stony Brook’s Waste Reduction and Management Institute’s work on two demonstration programs using processed MWC ash (using processed MSW combustor ash in both cold mix asphalt and construction quality cement blocks as well as a concrete block demonstration program) will be discussed. • Florida Department of Environmental Protection’s (FDEP’s) multifaceted program to address municipal combustion ash residue beneficial use determinations, ash regulation changes, and its analysis of statewide total metals data will be reviewed.

In the 1980’s, California faced landfill siting problems and a projected shortage of landfill capacity that could impact the health and safety in California. To address this issue, the California Integrated Waste Management Act was passed in 1990 and established a framework to limit reliance on landfills. This framework gives greater emphasis to recycling, waste prevention, source reduction, and composting. The Integrated Waste Management Act required each city and county to implement plans to divert 25% of solid waste by 1995 and 50% by 2000 from landfills. Although we have achieved a 47% diversion rate and have 170 composting facilities, we still have approximately 30 millions tons of material being landfilled. This may be an untapped resource for energy and alternative fuels production.