Waste-to-energy plant

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A waste-to-energy plant in Saugus, Massachusetts, the first plant in the United States. Wheelabrator Waste-to-Energy Plant, Saugus MA.jpg
A waste-to-energy plant in Saugus, Massachusetts, the first plant in the United States.
Waste-to-energy generating capacity in the United States U.S. installed waste-to-energy electricity generating capacity in 1980 through 2027 (52321033217).png
Waste-to-energy generating capacity in the United States

A waste-to-energy plant is a waste management facility that combusts wastes to produce electricity. This type of power plant is sometimes called a trash-to-energy, municipal waste incineration, energy recovery, or resource recovery plant.

Contents

Modern waste-to-energy plants are very different from the trash incinerators that were commonly used until a few decades ago. Unlike modern ones, those plants usually did not remove hazardous or recyclable materials before burning. These incinerators endangered the health of the plant workers and the nearby residents, and most of them did not generate electricity.

Waste-to-energy generation is being increasingly looked at as a potential energy diversification strategy, especially by Sweden, which has been a leader in waste-to-energy production over the past 20 years. The typical range of net electrical energy that can be produced is about 500 to 600 kWh of electricity per ton of waste incinerated. [1] Thus, the incineration of about 2,200 tons per day of waste will produce about 1,200 MWh of electrical energy.

Operation

Waste-to-energy plants in the United States U.S. waste-to-energy power plant locations as of June 2022 (52322241545).png
Waste-to-energy plants in the United States

Most waste-to-energy plants burn municipal solid waste, but some burn industrial waste or hazardous waste. A modern, properly run waste-to-energy plant sorts material before burning it and can co-exist with recycling. The only items that are burned are not recyclable, by design or economically, and are not hazardous.

Waste-to-energy plants are similar in their design and equipment with other steam-electric power plants, particularly biomass plants. First, the waste is brought to the facility. Then, the waste is sorted to remove recyclable and hazardous materials. The waste is then stored until it is time for burning. A few plants use gasification, but most combust the waste directly because it is a mature, efficient technology. The waste can be added to the boiler continuously or in batches, depending on the design of the plant.

In terms of volume, waste-to-energy plants incinerate 80 to 90 percent of waste. Sometimes, the residue ash is clean enough to be used for some purposes such as raw materials for use in manufacturing cinder blocks or for road construction. In addition, the metals that may be burned are collected from the bottom of the furnace and sold to foundries. Some waste-to-energy plants convert salt water to potable fresh water as a by-product of cooling processes.

Cost

The typical plant with a capacity of 400 GWh energy production annually costs about 440 million dollars to build. Waste-to-energy plants may have a significant cost advantage over traditional power options, as the waste-to-energy operator may receive revenue for receiving waste as an alternative to the cost of disposing of waste in a landfill, typically referred to as a "tipping fee" per ton basis, versus having to pay for the cost of fuel, whereas fuel cost can account for as much as 45 percent of the cost to produce electricity in a coal-powered plant, and 75 percent or more of the cost in a natural gas-powered plant. The National Solid Waste Management Association estimates that the average United States tipping fee for 2002 was $33.70 per ton.

Pollution

Waste-to-energy plants cause less air pollution than coal plants, but more than natural gas plants. [2] At the same time, it is carbon-negative: processing waste into fuel releases considerably less carbon and methane into the air than having waste decay away in landfills or bodies of water. [3]

Waste-to-energy plants are designed to reduce the emission of air pollutants in the flue gases exhausted to the atmosphere, such as nitrogen oxides, sulfur oxides and particulates, and to destroy pollutants already present in the waste, using pollution control measures such as baghouses, scrubbers, and electrostatic precipitators. High temperature, efficient combustion, and effective scrubbing and controls can significantly reduce air pollution outputs.

Burning municipal waste does produce significant amounts of dioxin and furan emissions [4] to the atmosphere as compared to the smaller amounts produced by burning coal or natural gas. Dioxins and furans are considered by many to be serious health hazards. However, advances in emission control designs and very stringent new governmental regulations, as well as public opposition to municipal waste incinerators, have caused large reductions in the amount of dioxins and furans produced by waste-to-energy plants.

Waste-to-energy plants produce fly ash and bottom ash just as is the case when coal is combusted. The total amount of ash produced by waste-to-energy plants ranges from 15% to 25% by weight of the original quantity of waste, and the fly ash amounts to about 10% to 20% of the total ash. [1] The fly ash, by far, constitutes more of a potential health hazard than does the bottom ash because the fly ash contains toxic metals such as lead, cadmium, copper, and zinc as well as small amounts of dioxins and furans. [5] The bottom ash may or may not contain significant levels of health hazardous materials. In the United States, and perhaps in other countries as well, the law requires that the ash be tested for toxicity before disposal in landfills. If the ash is found to be hazardous, it can only be disposed of in landfills which are carefully designed to prevent pollutants in the ash from leaching into underground aquifers.

Odor pollution can be a problem when the plant location is not isolated. Some plants store the waste in an enclosed area with a negative pressure, which prevents unpleasant odors from escaping, and the air drawn from the storage area is sent through the boiler or a filter. However, not all plants take steps to reduce the odor, resulting in complaints.

An issue that affects community relationships is the increased road traffic of garbage trucks to transport municipal waste to the waste-to-energy facility. Due to this reason, most waste-to-energy plants are located in industrial areas.

Landfill gas, which contains about 50% methane, and 50% carbon dioxide, is contaminated with a small amount of pollutants. Unlike at waste-to-energy plants, there are little or no pollution controls on the burning of landfill gas. The gas is usually flared or used to run a reciprocating engine or microturbine, especially in digester gas power plants. Cleaning up the landfill gas is usually not cost effective because natural gas, which it substitutes for, is relatively cheap.

See also

Related Research Articles

<span class="mw-page-title-main">Hazardous waste</span> Ignitable, reactive, corrosive and/or toxic unwanted or unusable materials

Hazardous waste is waste that has substantial or potential threats to public health or the environment. Hazardous waste is a type of dangerous goods. They usually have one or more of the following hazardous traits: ignitability, reactivity, corrosivity, toxicity. Listed hazardous wastes are materials specifically listed by regulatory authorities as hazardous wastes which are from non-specific sources, specific sources, or discarded chemical products. Hazardous wastes may be found in different physical states such as gaseous, liquids, or solids. A hazardous waste is a special type of waste because it cannot be disposed of by common means like other by-products of our everyday lives. Depending on the physical state of the waste, treatment and solidification processes might be required.

<span class="mw-page-title-main">Waste management</span> Activities and actions required to manage waste from its source to its final disposal

Waste management or waste disposal includes the processes and actions required to manage waste from its inception to its final disposal. This includes the collection, transport, treatment, and disposal of waste, together with monitoring and regulation of the waste management process and waste-related laws, technologies, and economic mechanisms.

<span class="mw-page-title-main">Landfill</span> Site for the disposal of waste materials

A landfill site, also known as a tip, dump, rubbish dump, garbage dump, or dumping ground, is a site for the disposal of waste materials. Landfill is the oldest and most common form of waste disposal, although the systematic burial of the waste with daily, intermediate and final covers only began in the 1940s. In the past, refuse was simply left in piles or thrown into pits; in archeology this is known as a midden.

<span class="mw-page-title-main">Incineration</span> Waste treatment process

Incineration is a waste treatment process that involves the combustion of substances contained in waste materials. Industrial plants for waste incineration are commonly referred to as waste-to-energy facilities. Incineration and other high-temperature waste treatment systems are described as "thermal treatment". Incineration of waste materials converts the waste into ash, flue gas and heat. The ash is mostly formed by the inorganic constituents of the waste and may take the form of solid lumps or particulates carried by the flue gas. The flue gases must be cleaned of gaseous and particulate pollutants before they are dispersed into the atmosphere. In some cases, the heat that is generated by incineration can be used to generate electric power.

<span class="mw-page-title-main">Fossil fuel power station</span> Facility that burns fossil fuels to produce electricity

A fossil fuel power station is a thermal power station which burns a fossil fuel, such as coal or natural gas, to produce electricity. Fossil fuel power stations have machinery to convert the heat energy of combustion into mechanical energy, which then operates an electrical generator. The prime mover may be a steam turbine, a gas turbine or, in small plants, a reciprocating gas engine. All plants use the energy extracted from the expansion of a hot gas, either steam or combustion gases. Although different energy conversion methods exist, all thermal power station conversion methods have their efficiency limited by the Carnot efficiency and therefore produce waste heat.

<span class="mw-page-title-main">Municipal solid waste</span> Type of waste consisting of everyday items discarded by the public

Municipal solid waste (MSW), commonly known as trash or garbage in the United States and rubbish in Britain, is a waste type consisting of everyday items that are discarded by the public. "Garbage" can also refer specifically to food waste, as in a garbage disposal; the two are sometimes collected separately. In the European Union, the semantic definition is 'mixed municipal waste,' given waste code 20 03 01 in the European Waste Catalog. Although the waste may originate from a number of sources that has nothing to do with a municipality, the traditional role of municipalities in collecting and managing these kinds of waste have produced the particular etymology 'municipal.'

<span class="mw-page-title-main">Waste-to-energy</span> Process of generating energy from the primary treatment of waste

Waste-to-energy (WtE) or energy-from-waste (EfW) is the process of generating energy in the form of electricity and/or heat from the primary treatment of waste, or the processing of waste into a fuel source. WtE is a form of energy recovery. Most WtE processes generate electricity and/or heat directly through combustion, or produce a combustible fuel commodity, such as methane, methanol, ethanol or synthetic fuels, often derived from the product syngas.

<span class="mw-page-title-main">Bottom ash</span> Solid residue of combustion in the lower part of an industrial oven

Bottom ash is part of the non-combustible residue of combustion in a power plant, boiler, furnace or incinerator. In an industrial context, it has traditionally referred to coal combustion and comprises traces of combustibles embedded in forming clinkers and sticking to hot side walls of a coal-burning furnace during its operation. The portion of the ash that escapes up the chimney or stack is, however, referred to as fly ash. The clinkers fall by themselves into the bottom hopper of a coal-burning furnace and are cooled. The above portion of the ash is also referred to as bottom ash.

There are a number of different waste treatment technologies for the disposal, recycling, storage, or energy recovery from different waste types. Each type has its own associated methods of waste management.

Plasma gasification is an extreme thermal process using plasma which converts organic matter into a syngas which is primarily made up of hydrogen and carbon monoxide. A plasma torch powered by an electric arc is used to ionize gas and catalyze organic matter into syngas, with slag remaining as a byproduct. It is used commercially as a form of waste treatment, and has been tested for the gasification of refuse-derived fuel, biomass, industrial waste, hazardous waste, and solid hydrocarbons, such as coal, oil sands, petcoke and oil shale.

<span class="mw-page-title-main">Sheffield Energy Recovery Facility</span>

The Sheffield Energy Recovery Facility, also known as the Energy from Waste Plant, is a modern incinerator which treats Sheffield's household waste. It is notable as it not only provides electricity from the combustion of waste but also supplies heat to a local district heating scheme, making it one of the most advanced, energy efficient incineration plants in the UK. In 2004, the district heating network prevented 15,108 tonnes of CO2 from being released from buildings across the city, compared to energy derived from fossil fuels. The incinerator is a 'static asset' owned by Sheffield City Council and operated by Veolia Environmental Services under a 35 year integrated waste management contract (IWMC)/PFI contract.

<span class="mw-page-title-main">Health and environmental impact of the coal industry</span>

The health and environmental impact of the coal industry includes issues such as land use, waste management, water and air pollution, caused by the coal mining, processing and the use of its products. In addition to atmospheric pollution, coal burning produces hundreds of millions of tons of solid waste products annually, including fly ash, bottom ash, and flue-gas desulfurization sludge, that contain mercury, uranium, thorium, arsenic, and other heavy metals. Coal is the largest contributor to the human-made increase of carbon dioxide in Earth's atmosphere.

<span class="mw-page-title-main">Tire-derived fuel</span>

Tire-derived fuel (TDF) is composed of shredded scrap tires. Tires may be mixed with coal or other fuels, such as wood or chemical wastes, to be burned in concrete kilns, power plants, or paper mills. An EPA test program concluded that, with the exception of zinc emissions, potential emissions from TDF are not expected to be very much different from other conventional fossil fuels, as long as combustion occurs in a well-designed, well-operated and well-maintained combustion device.

Waste management in Japan today emphasizes not just the efficient and sanitary collection of waste, but also reduction in waste produced and recycling of waste when possible. This has been influenced by its history, particularly periods of significant economic expansion, as well as its geography as a mountainous country with limited space for landfills. Important forms of waste disposal include incineration, recycling and, to a smaller extent, landfills and land reclamation. Although Japan has made progress since the 1990s in reducing waste produced and encouraging recycling, there is still further progress to be made in reducing reliance on incinerators and the garbage sent to landfills. Challenges also exist in the processing of electronic waste and debris left after natural disasters.

<span class="mw-page-title-main">Teesside EfW</span> Power station in Billingham, UK

Teesside Energy from Waste plant is a municipal waste incinerator and waste-to-energy power station, which provides 29.2 megawatts (MW) of electricity for the National Grid by burning 390,000 tonnes of household and commercial waste a year. It is located on the River Tees at Haverton Hill, east of Billingham in North East England. Developed and built by NEM, a subsidiary of Northumbrian Water, the initial plant replaced the Portrack Incinerator and opened in 1998. Subsequently, the facility became part of SITA, now Suez.

<span class="mw-page-title-main">Environmental effects of paper</span> Overview about the environmental effects of the paper production industry

The environmental effects of paper are significant, which has led to changes in industry and behaviour at both business and personal levels. With the use of modern technology such as the printing press and the highly mechanized harvesting of wood, disposable paper became a relatively cheap commodity, which led to a high level of consumption and waste. The rise in global environmental issues such as air and water pollution, climate change, overflowing landfills and clearcutting have all lead to increased government regulations. There is now a trend towards sustainability in the pulp and paper industry as it moves to reduce clear cutting, water use, greenhouse gas emissions, fossil fuel consumption and clean up its influence on local water supplies and air pollution.

Solid waste policy in the United States is aimed at developing and implementing proper mechanisms to effectively manage solid waste. For solid waste policy to be effective, inputs should come from stakeholders, including citizens, businesses, community-based organizations, non-governmental organizations, government agencies, universities, and other research organizations. These inputs form the basis of policy frameworks that influence solid waste management decisions. In the United States, the Environmental Protection Agency (EPA) regulates household, industrial, manufacturing, and commercial solid and hazardous wastes under the 1976 Resource Conservation and Recovery Act (RCRA). Effective solid waste management is a cooperative effort involving federal, state, regional, and local entities. Thus, the RCRA's Solid Waste program section D encourages the environmental departments of each state to develop comprehensive plans to manage nonhazardous industrial and municipal solid waste.

An advanced thermal recycling system is an advancement of existing energy-from-waste (EfW) technology. An ATR system converts municipal solid waste (MSW) into electricity or steam for district heating or industrial customers. The combustion bottom ash and the combustion fly ash, along with the air pollution control system fly ash, are treated to produce products that can be beneficially reused. Specifically, ATR systems consist of the following:

<span class="mw-page-title-main">Wheelabrator Incinerator</span> Waste-to-energy incinerator in Baltimore, Maryland, US

Wheelabrator Baltimore is a waste-to-energy incinerator located in the Westport neighborhood of Baltimore, Maryland and is operated by Wheelabrator Technologies, a subsidiary of Energy Capital Partners. It has an electric generation capacity of 64.5 megawatts. On October 2, 2018, ECP announced the agreement to sell Wheelabrator Technologies to Macquarie Infrastructure Partners, a subsidiary of Macquarie Group.

<span class="mw-page-title-main">Waste in the United Kingdom</span>

It is estimated that 290 million tonnes of waste was produced in the United Kingdom in 2008 but volumes are declining. In 2012 municipal solid waste generation was almost 30 million tonnes, according to Waste Atlas Platform.

References

  1. 1 2 The ABC of Integrated Waste Management
  2. Waste-to-Energy Compared to Fossil Fuels for Equal Amounts of Energy (Delaware Solid Waste Authority)
  3. "Energy from Waste: Greenhouse Gas Winner or Pollution Loser?". www.powermag.com. July 2016. Retrieved 2019-06-02.
  4. Beychok, M.R., A data base of dioxin and furan emissions from municipal refuse incinerators, Atmospheric Environment, Elsevier B.V., January 1987
  5. University of Toronto, PhD Thesis Chan, C.C., Behaviour of metals in MSW fly ash during roasting with chlorinating agents, Chemical Engineering Department, University of Toronto, 1997.