Unit 3: Types of Waste and their Energy Potential
Expert-defined terms from the Professional Certificate in Waste-to-Energy Conversion course at London School of Business and Administration. Free to read, free to share, paired with a globally recognised certification pathway.
Anaerobic Digestion #
a biological process that breaks down organic matter in the absence of oxygen, producing biogas (a mixture of methane and carbon dioxide) and digestate (a nutrient-rich soil amendment). Related terms include biogas, biomethane, and digestate.
Ash #
the non-combustible residue left after the combustion of waste. There are two types of ash: bottom ash, which is collected at the bottom of the combustion chamber, and fly ash, which is carried away by the flue gases and collected in the air pollution control system.
Biomass #
organic matter that can be converted into fuel, such as wood, agricultural waste, and municipal solid waste. Biomass is a renewable energy source that can be used to generate electricity, heat, and transportation fuels.
Biomethane #
a type of biogas that has been upgraded to contain at least 90% methane. Biomethane can be used as a vehicle fuel or injected into the natural gas grid.
Bottom Ash #
the non-combustible residue that is collected at the bottom of the combustion chamber during waste-to-energy conversion. Bottom ash can be used as a construction material or landfilled.
Carbon Capture and Storage (CCS) #
a technology that captures carbon dioxide emissions from industrial processes and stores them underground, preventing them from being released into the atmosphere. CCS is an important tool for reducing greenhouse gas emissions and mitigating climate change.
Circular Economy #
an economic system that is based on the principles of reducing, reusing, and recycling resources, rather than the traditional linear model of "take, make, use, dispose." A circular economy aims to keep resources in use for as long as possible, extracting the maximum value from them while minimizing waste and environmental impact.
Combustion #
the process of burning waste in the presence of oxygen to produce heat and electricity. Combustion is the most common method of waste-to-energy conversion.
Digestate #
the nutrient-rich soil amendment produced during anaerobic digestion. Digestate can be used as a fertilizer or soil conditioner.
Energy Crops #
plants that are grown specifically for use as a fuel or energy source. Energy crops can be used to produce biomass, biogas, or bioethanol.
Energy Recovery #
the process of converting waste into usable heat, electricity, or fuel. Energy recovery is an important aspect of waste management, as it allows valuable resources to be extracted from waste and reduces the need for landfilling.
Flue Gas #
the mixture of gases that is produced when waste is burned in a combustion chamber. Flue gas contains pollutants such as particulate matter, nitrogen oxides, and sulfur dioxide, which must be removed before the gas is released into the atmosphere.
Fly Ash #
the non-combustible residue that is carried away by the flue gases during waste-to-energy conversion. Fly ash is collected in the air pollution control system and can be used as a construction material or landfilled.
Gasification #
a thermal process that converts waste into a synthetic gas, or "syngas," which can be used to generate electricity or produce chemicals. Gasification is an alternative to combustion, as it occurs in a lower-oxygen environment and produces fewer pollutants.
Greenhouse Gases #
gases that trap heat in the atmosphere, leading to global warming and climate change. The main greenhouse gases are carbon dioxide, methane, and nitrous oxide.
Incineration #
the combustion of waste in a controlled manner to reduce its volume and produce heat and electricity. Incineration is a common method of waste-to-energy conversion.
Landfill Gas #
the mixture of gases that is produced when organic waste decomposes in a landfill. Landfill gas is composed mainly of methane and carbon dioxide and can be used to generate electricity or heat.
Mechanical Biological Treatment (MBT) #
a process that combines mechanical and biological methods to treat municipal solid waste. MBT can be used to recover recyclable materials, produce a solid fuel for energy recovery, or stabilize waste before landfilling.
Methane #
a potent greenhouse gas that is produced during the anaerobic digestion of organic matter. Methane can be captured and used as a fuel or converted into biomethane.
Municipal Solid Waste (MSW) #
the solid waste that is generated by households, businesses, and institutions in a given area. MSW is typically composed of a variety of materials, including paper, plastic, metal, glass, and organic waste.
Organic Waste #
waste that is composed of plant or animal material, such as food scraps, yard waste, and sewage sludge. Organic waste can be used to produce biogas or compost.
Plastic Waste #
waste that is composed of plastic materials, such as plastic bags, bottles, and packaging. Plastic waste is a significant environmental problem, as it takes hundreds of years to decompose and can cause harm to wildlife and ecosystems.
Pyrolysis #
a thermal process that decomposes organic materials in the absence of oxygen, producing a synthetic gas, oil, and char. Pyrolysis is an alternative to combustion and gasification, as it occurs in a zero-oxygen environment and produces fewer pollutants.
Refuse #
Derived Fuel (RDF): a solid fuel that is produced by shredding and sorting municipal solid waste. RDF is typically composed of combustible materials such as paper, plastic, and textiles and can be used to generate electricity or heat.
Renewable Energy #
energy that is produced from sources that are replenished naturally, such as wind, solar, and biomass. Renewable energy is an important tool for reducing greenhouse gas emissions and mitigating climate change.
Resource Recovery #
the process of extracting valuable materials or energy from waste. Resource recovery is an important aspect of waste management, as it allows resources to be reused or recycled and reduces the need for landfilling.
Syngas #
a synthetic gas that is produced during gasification or pyrolysis. Syngas is composed mainly of hydrogen, carbon monoxide, and methane and can be used to generate electricity or produce chemicals.
Thermal Treatment #
the use of heat to convert waste into a usable form, such as electricity, heat, or fuel. Thermal treatment includes methods such as combustion, gasification, and pyrolysis.
Waste #
to-Energy (WtE): the conversion of waste into usable heat, electricity, or fuel. Waste-to-energy is an important aspect of waste management, as it allows valuable resources to be extracted from waste and reduces the need for landfilling.
Waste #
to-Fuel: the conversion of waste into a fuel, such as biogas, syngas, or refuse-derived fuel. Waste-to-fuel is an alternative to waste-to-energy, as it focuses on the production of a specific fuel rather than heat or electricity.
Waste #
to-Heat: the conversion of waste into heat. Waste-to-heat is an aspect of waste-to-energy, as it focuses on the production of heat rather than electricity.
Waste #
to-Power: the conversion of waste into electricity. Waste-to-power is an aspect of waste-to-energy, as it focuses on the production of electricity rather than heat.
Waste Management #
the collection, transportation, and disposal of waste. Waste management includes methods such as landfilling, recycling, and waste-to-energy conversion.
Zero Waste #
a philosophy and goal that aims to eliminate waste and maximize resource recovery. Zero waste involves reducing, reusing, and recycling resources, as well as designing products and systems to minimize waste and pollution.