– A –
AEROBIC DECOMPOSITION – a type of decomposition that requires oxygen
ANAEROBIC DIGESTION – decomposition of biological wastes by micro-organisms, usually under wet conditions, in the absence of air (oxygen), to produce a gas comprising mostly methane and carbon dioxide
– B –
BALE – a compacted and bound cube of recycled material
BALER – a machine used to compress recyclables into bundles to reduce volume, balers are often used on newspaper, plastics, and corrugated cardboard
BIODEGRADABLE MATERIAL – any organic material that can be broken down by microorganisms into simpler, more stable compounds, most organic wastes (e.g., food, paper) are biodegradable
BIOMASS – any organic matter that is available on a renewable or recurring basis, including agricultural crops and trees, wood and wood residues, plants (including aquatic plants), grasses, animal manure, municipal residues, and other residue materials. Biomass is generally produced in a sustainable manner from water and carbon dioxide by photosynthesis. There are three main categories of biomass – primary, secondary, and tertiary.
BTU (BRITISH THERMAL UNIT) – a unit of measure for the amount of energy a given material contains (e.g., energy released as heat during combustion is measured in Btu’s.) Technically, one Btu is the quantity of heat required to raise the temperature of one pound of water one degree Fahrenheit.
BULKY WASTE – large wastes such as appliances, furniture, trees and branches, that cannot be handled by normal MSW processing methods.
– C –
CLEAN FILL – material that will have no harmful effects on the environment and which consists of rocks or soil arising from the excavation of undisturbed material.
COLLECTION – the process of picking up wastes from residences, businesses, or a collection point, loading them into a vehicle, and transporting them to a processing, transfer, or disposal site.
COMBUSTIBLES – burnable materials in the waste stream, including paper, plastics, wood, and food and garden wastes.
COMMINGLED – mixed recyclables that are collected together after having been separated from mixed MSW.
COMPOSTING – the controlled biological decomposition of organic solid materials under aerobic conditions.
CONSTRUCTION & DEMOLITION DEBRIS (C&D) – waste generated by construction
and demolition of buildings, such as bricks, concrete, drywall, lumber, miscellaneous metal parts and sheets, packaging materials, etc.
CONVEYING LINE – a conveyor belt assembly that is used in a facility such as a MRF to move materials from the tipping floor/pit to other areas of the facility.
COVER MATERIAL – material, either natural soil or geosynthetic material, used in a landfill to impede water infiltration, landfill gas emissions, and bird and rodent congregation. It is also used to control odors and make the site more visually attractive. Landfills have three forms of cover: daily cover, intermediate cover, and final cover.
CURBSIDE COLLECTION – programs in which recyclable materials are collected at the curb, often from special containers, and then taken to various processing facilities
– D –
DENSIFIED REFUSE-DERIVED FUEL (D-RDF) – refuse-derived fuel that has been compressed or compacted through such processes as pelletizing, briquetting, or extruding. Densifying materials makes them easier to handle or improves their burning characteristics.
DISK SCREEN – a device used to separate materials by size and weight. A series of disks are spaced on a series of spaced axles to form a screen bed. As the axles and disks spin they propel oversized material across the bed while undersized materials fall between the disks. Inclining and tilting the bed allows a weight-based separation as heavier materials move down the tilt as lighter materials are propelled up the incline by the disks. Disk and axle spacing, disk shape and size (oval, finger, star), disk material, incline and tilt may all be varied to optimize the sorts desired. Frequently used in MRFs to separate OCC and paper from containers.
DISPOSAL – the final handling of solid waste, following collection, processing, or incineration. Disposal most often means placement of wastes in a dump or a landfill.
DIVERSION RATE – the proportion of waste material diverted for recycling, composting, or reuse and away from landfilling or incineration.
DROP-OFF COLLECTION – a method of collecting recyclable or compostable materials in which the materials are taken by individuals to collection sites, where they deposit the materials into designated containers.
– E –
EDDY CURRENT SEPARATOR – a separation device which uses either powerful spinning, permanent magnets or pulsed electromagnets that produce repelling forces on non-ferrous metals. They are typically used by recyclers to positively-sort aluminum cans or to remove bits of metal contamination from granulated plastics or glass cullet.
EMISSIONS – gases released into the atmosphere.
ENERGY RECOVERY – the process of extracting useful energy from waste, typically from the heat produced by incineration or via methane gas from landfills.
ENVIRONMENTAL IMPACT ASSESSMENT (EIA) – an evaluation designed to identify and predict the impact of an action or a project on the environment and human health and wellbeing. Can include risk assessment as a component, along with economic & land use assessment.
ENVIRONMENTAL RISK ASSESSMENT (ENRA) – an evaluation of the interactions of agents, humans, and ecological resources. Comprised of human health risk assessment and ecological risk assessment, typically evaluating the probabilities and magnitudes of harm that could come from environmental contaminants.
E-SCRAP (e-waste)– obsolete electronic equipment including computers, monitors, VCRs, televisions, etc. (see: brown goods)
– F –
FEEDSTOCK – a product used as the basis for manufacture of another product.
FERROUS METALS (FE) – metals, which are predominantly composed of iron. Most ferrous metals, with the exception of some stainless steels, are magnetic and can be removed from commingled materials using large magnets at separation facilities.
FLUE GAS – all gasses and products of combustion that leave a furnace by way of a flue or duct.
FLUIDIZED BED COMBUSTOR – a type of RDF combustor (see below) that burns
materials directly on a layer of material having a high melting point, such as sand.
FLY ASH – small, solid particles of ash and soot generated when coal, oil, or waste materials are burned. Fly ash is suspended in the flue gas after combustion and is removed by pollution control equipment.
FOSSIL FUEL – solid, liquid, or gaseous fuels formed in the ground after millions of years by chemical and physical changes in plant and animal residues under high temperature and pressure. Oil, natural gas, and coal are fossil fuels.
– G –
GARBAGE – in everyday usage, refuse in general. Some MSWM manuals use garbage to mean “food wastes,” although this usage is not common.
GATE VOLUME – the amount of waste, measured by volume that enters a landfill.
GAYLORD BOX – a heavy corrugated box (4 feet square) that is used as a dumpster for collecting wastes and other materials.
GENERAL OBLIGATION (G.O.) BONDS – a method of financing in which bonds are backed by the faith and credit of a municipality.
GENERATION RATE – the amount of waste that is produced over a given amount of time. For example, a district may have a generation rate of 100 tons per day.
GREENHOUSE GASES – gases that trap the heat of the sun in the Earth’s atmosphere, producing the greenhouse effect. The two major greenhouse gases are water vapor and carbon dioxide. Other greenhouse gases include methane, ozone, chlorofluorocarbons, and nitrous oxide.
GROUNDWATER – water beneath the earth’s surface that fills underground pockets (known as aquifers), supplying wells and springs.
– H –
HAZARDOUS WASTE – waste material that exhibits a characteristic of hazardous waste as defined in RCRA (ignitability, corrosivity, reactivity, or toxicity), is listed specifically in RCRA 261.3 Subpart D, is a mixture of either, or is designated locally or by the state as hazardous or undesirable for handling as part of the municipal solid waste and would have to be treated as regulated hazardous waste if not from a household.
HEAT VALUE – heat generated per unit weight or volume of combustible material completely burned.
HEAVY METALS – metals of high atomic weight and density, such as mercury, lead, and cadmium, that are toxic to living organisms.
HIGH DENSITY POLYETHYLENE (HDPE) – used to make plastic bottles, milk cartons and other products. It produces toxic fumes when burned, often referred to as No. 2 Plastic.
HOUSEHOLD HAZARDOUS WASTE – products used in residences, such as paints and some cleaning compounds that are toxic to living organisms and/or the environment.
– I –
INCINERATION – the process of burning solid waste under controlled conditions to reduce its weight and volume, and often to produce energy.
INDUSTRIAL WASTE – materials discarded from industrial operations or derived from manufacturing processes.
INORGANIC WASTE – waste composed of material other than plant or animal matter, such as sand, dust, glass, and many synthetics. (i.e., contains no carbon).
INSTITUTIONAL WASTE – waste materials originating in schools, hospitals, prisons, research institutions, and other public buildings.
INTEGRATED SOLID WASTE MANAGEMENT – a practice using several alternative waste management techniques to manage and dispose of specific components of the municipal solid waste stream. Waste management alternatives include source reduction, recycling, composting, energy recovery, and landfilling.
IN-VESSEL COMPOSTING – a method in which compost is continuously and mechanically mixed and aerated in a large, contained area.
– L –
LANDFILL GASES – gases arising from the decomposition of organic wastes; principally methane, carbon dioxide, and hydrogen sulfide, such gases may cause explosions at landfills
LANDFILLING – the final disposal of solid waste by placing it in a controlled fashion in a place intended to be permanent.
LANDFILL MINING – a process of removing reusable resources from old landfills for recycling.
LEACHATE – liquid that has percolated through solid waste or another medium and has extracted, dissolved, or suspended materials from it. Because leachate may include potentially harmful materials, leachate collection and treatment are crucial at municipal waste landfills.
LOW DENSITY POLYETHYLENE (LDPE) – often referred as No. 4 Plastic.
– M –
MAGNETIC SEPARATION – a system to remove ferrous metals from other materials in a mixed municipal waste stream, magnets are used to collect the ferrous metals
MASS-BURN SYSTEM – a municipal waste combustion technology in which solid waste is burned in a controlled system without prior sorting or processing.
MATERIALS RECOVERY – obtaining materials that can be reused or recycled.
MATERIALS RECOVERY FACILITY (MRF) – a facility for separating commingled recyclables by manual or mechanical means. Some MRFs are designed to separate recyclables from mixed MSW. MRFs then bale and market the recovered materials.
MECHANICAL SEPARATION – the separation of waste into components using mechanical means, such as cyclones, trommels, and screens.
METHANE – an odorless, colorless, flammable, explosive gas produced by municipal solid waste undergoing anaerobic decomposition. Methane is emitted from municipal solid waste landfills.
MOISTURE CONTENT – the fraction or percentage of a substance or soil that is water.
MUNICIPAL (PROJECT) REVENUE BOND – A method of financing in which bonds are given on the basis of the worthiness, technological feasibility, and projected revenue of a project.
MUNICIPAL SOLID WASTE (MSW) – all solid waste generated in an area except industrial and agricultural wastes. Sometimes includes construction and demolition debris and other special wastes that may enter the municipal waste stream. Generally excludes hazardous wastes except to the extent that they enter the municipal waste stream. Sometimes defined to mean all solid wastes that a city authority accepts responsibility for managing in some way.
MUNICIPAL SOLID WASTE MANAGEMENT (MSWM) – planning and implementation of systems to handle MSW.
– N –
NEGATIVE SORT– refers to when a desired recyclable is left on the sorting belt while contaminants and other recyclables are removed. Negative sorts are used to minimize handling when the bulk of the stream to be sorted consists of one material. Often used after mechanical separation for quality control.
NIMBY – acronym for “not in my back yard.” An expression frequently used by residents whose opposition to siting a waste management facility is based on the facility’s proposed location.
NON-FERROUS SCRAP METALS (NF)– metals, which contain no iron, such as aluminum, copper, brass and bronze.
– O –
OPEN DUMP – an unplanned “landfill” that incorporates few if any of the characteristics of a controlled landfill. There is typically no leachate control, no access control, no cover, no management, and many waste pickers.
ORGANIC WASTE – technically, waste containing carbon, including paper, plastics, wood, food wastes, and yard wastes. In practice in MSWM, the term is often used in a more restricted sense to mean material that is more directly derived from plant or animal sources, and which can generally be decomposed by microorganisms.
– P –
PARTICULATE MATTER (PM) – tiny pieces of matter resulting from the combustion process. PM can have harmful health effects when breathed. Pollution control at combustion facilities is designed to limit particulate emissions.
PATHOGENS – disease-causing agents, especially microorganisms such as bacteria, viruses, and fungi.
PERCOLATE – to ooze or trickle through a permeable substance. Groundwater may percolate into the bottom of an unlined landfill.
PILOT PROGRAM – a trial run of the planned program conducted on a small scale to forecast the workability of the planned program. Changes may be made to the program depending on the results of the pilot study.
POLLUTION – the contamination of soil, water, or the atmosphere by the discharge of waste or other offensive materials
POLYETHYLENE TEREPHTHALATE (PET OR PETE)– a type of plastic that is clear or colored transparent with high gloss. It is used for carbonated beverage bottles and some household cleanser containers. Often referred to as No. 1 Plastic.
POLYPROPYLENE (PP) – plastic with a smooth surface that and is difficult to scratch. Typical uses are: battery cases, dairy tubs, jar lids, straws and syrup bottles. More frequently found in consumer goods than disposable packaging. It is hard to collect in marketable quantities for recycling and has limited uses in its recycled form. Often referred to as No. 5 Plastic.
POLYSTYRENE (PS) – a plastic with a smooth surface that cracks easily when bent. Used for disposable packaging and utensils, Styrofoam cups and shipping packing (peanuts). Also widely used in consumer products such as toys. Often referred to as No. 6 Plastic.
POLYVINYL CHLORIDE (PVC) – an environmentally stable plastic. It is used for food wraps, blister-type packaging and containers for personal care products, plumbing, siding, toys and credit cards. Because of its chlorine content, it should not be burned, often referred to as V-3 or No. 3 plastic
POSITIVE SORT– refers to when a desired recyclable is specifically removed from the stream of materials on the sorting line either by hand picking or by a device designed for that purpose. See: Negative sort.
POST CLOSURE CARE – a procedure of maintaining the environmental controls and appearance of a landfill after it has ceased to accept waste.
POST CONSUMER MATERIAL – any household or commercial product, which has served its original, intended use.
POST CONSUMER RECYCLING – the reuse of materials generated from residential and commercial waste, excluding recycling of material from industrial processes that has not reached the consumer, such as glass broken in the manufacturing process.
POST INDUSTRIAL MATERIAL – industrial manufacturing scrap.
PRIMARY MATERIAL – a commercial material produced from virgin materials used for manufacturing basic products. Examples include wood pulp, iron ore, and silica sand.
PRIVATIZATION – a general term referring to a range of contracts and other agreements that transfer the provision of some services or production from the public sector to private firms or organizations.
PROCESSING – preparing MSW materials for subsequent use or management, using processes such as baling, magnetic separation, crushing, and shredding. The term is also sometimes used to mean separation of recyclables from mixed MSW.
PUTRESCIBLE – subject to decomposition or decay. Usually used in reference to food wastes and other organic wastes that decay quickly.
PYROLYSIS – chemical decomposition of a substance by heat in the absence of oxygen, resulting in various hydrocarbon gases and carbon-like residue.
– R –
RECYCLABLES – items that can be reprocessed into feedstock for new products. Common examples are paper, glass, aluminum, corrugated cardboard and plastic containers.
RECYCLING – the processes by which materials otherwise destined for disposal are collected, reprocessed, or remanufactured, and are reused.
REFUSE – a term often used interchangeably with solid waste.
REFUSE-DERIVED FUEL (RDF) – product of a mixed waste processing system in which certain recyclable and non-combustible materials are removed, with the remaining combustible material converted for use as a fuel to create energy.
RESIDENTIAL WASTE – waste generated in single and multiple-family homes.
RESIDUE – the materials remaining after processing, incineration, composting, or recycling. Residues are usually disposed of in landfills.
RESOURCE RECOVERY – a term describing the extraction and use of materials and energy from the waste stream. The term is sometimes used synonymously with energy recovery.
REUSE – the use of a product more than once in its same form for the same purpose; e.g., a soft drink bottle is reused when it is returned to the bottling company for refilling.
ROLL-OFF CONTAINER – a large waste container that fits onto a tractor trailer that can be dropped off and picked up hydraulically.
RUBBISH – a general term for solid waste, sometimes used to exclude food wastes and ashes
– S –
SANITARY LANDFILL – an engineered method of disposing of solid waste on land, in a manner that meets most of the standard specifications, including sound siting, extensive site preparation, proper leachate and gas management and monitoring, compaction, daily and final cover, complete access control, and record-keeping.
SCRAP – discarded or rejected industrial waste material often suitable for recycling.
SCRUBBER – common anti-pollution device that uses a liquid or slurry spray to remove acid gases and particulates from municipal waste combustion facility flue gases.
SECONDARY LEACHATE – when water percolates through a landfill, the water becomes contaminated and becomes leachate. This leachate is known as secondary leachate.
SECONDARY MATERIAL – a material that is used in place of a primary or raw material in manufacturing a product.
SECURE LANDFILL – a disposal facility designed to permanently isolate wastes from the environment. This entails burial of the wastes in a landfill that includes clay and/ or synthetic liners, leachate collection, gas collection (in cases where gas is generated), and an impermeable cover.
SEDIMENTATION BASIN – An excavated area of land that is used to allow solid particles in water to settle out. The rate of sedimentation is dependent on the depth of the basin and the size and weight of the particles.
SET-OUT CONTAINER – a box or bucket used for residential waste that is placed outside for collection.
SETTLEMENT – As refuse decomposes and/or becomes compacted by the weight of overlaying layers, landfills experience a volume decrease and compaction of individual layers of waste in the landfill. Settlement refers to this volume decrease and compaction of layers.
SEWAGE SLUDGE – a semi-liquid residue that settles to the bottom of canals and pipes carrying sewage or industrial wastewaters, or in the bottom of tanks used in treating wastewaters.
SHREDDER – a mechanical device used to break waste materials into smaller pieces by tearing and impact action. Shredding solid waste is done to minimize its volume or make it more readily combustible.
SITE REMEDIATION – treatment of a contaminated site by removing contaminated solids or liquids or treating them on-site.
SOIL BORING – a sample of earth representing underground conditions for the surrounding area. They are used to gather information about and model subsurface characteristics, which are important when designing landfills.
SOLID WASTE – any garbage, or refuse, sludge from a wastewater treatment plant, water supply treatment plant, or air pollution control facility and other discarded material, including solid, liquid, semi-solid, or contained gaseous material resulting from industrial, commercial, mining, and agricultural operations, and from community activities, but does not include solid or dissolved materials in domestic sewage, or solid or dissolved materials in irrigation return flows or industrial discharges that are point sources subject to permit under 33 U.S.C. 1342, or source, special nuclear, or by-product materials as defined by the Atomic Energy Act of 1954, as amended (68 Stat. 923). (Definition from 40CFR 258.2.)
SOURCE REDUCTION – the design, manufacture, acquisition, and reuse of materials so as to minimize the quantity and/or toxicity of waste produced. Source reduction prevents waste either by redesigning products or by otherwise changing societal patterns of consumption, use, and waste generation. (See also, “waste reduction.”)
SOURCE SEPARATION – the segregation of specific materials at the point of generation for separate collection. Residential generators source separate recyclables as part of curbside recycling programs.
SPECIAL WASTE – Refers to items that require special or separate handling, such as household hazardous wastes, bulky wastes, tires, and used oil.
SUBSIDY – direct or indirect payment from government to businesses, citizens, or institutions to encourage a desired activity.
SUBTITLE C – The hazardous waste section of the Resource Conservation and Recovery Act (RCRA) of 1976.
SUBTITLE D – The solid, nonhazardous waste section of the Resource Conservation and Recovery Act (RCRA) of 1976.
SUBTITLE F – Section of the Resource Conservation and Recovery Act (RCRA) of 1976 requiring the federal government to actively participate in procurement programs fostering the recovery and use of recycled materials and energy.
SUPERFUND – common name for the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) to clean up abandoned or inactive hazardous waste dump sites.
– T –
TIPPING FEE – a fee charged for the unloading or dumping of material at a landfill, transfer station, recycling center, or waste-to-energy facility, usually stated in dollars per ton (Sometimes called a disposal or service fee.)
TIPPING FLOOR/PIT – unloading area for vehicles that are delivering municipal solid waste to a transfer station or municipal waste combustion facility.
TRANSFER – the act of moving waste from a collection vehicle to a larger transport vehicle
TRANSFER STATION – a permanent facility where waste materials are taken from smaller collection vehicles and placed in larger vehicles for transport, including truck trailers, railroad cars, or barges. Recycling and some processing may also take place at transfer stations.
TROMMEL – a perforated, rotating, horizontal cylinder that may be used in resource recovery facilities to break open trash bags, remove glass in large enough pieces for easy recovery, and remove small abrasive items such as stones and dirt. Trommels have also been used to remove steel cans from incinerator residue.
– V –
VECTORS – organisms that carry disease causing pathogens. At landfills rodents, flies, and birds are the main vectors that spread pathogens beyond the landfill site.
VIRGIN MATERIALS – any basic material for industrial processes that has not previously been used, for example, wood-pulp trees, iron ore, crude oil, and bauxite.
– W –
WASTE CHARACTERIZATION STUDY – an analysis of samples from a waste stream to determine its composition.
WASTE COLLECTOR – a person employed by a local authority or a private firm to collect waste from residences, businesses, and community bins.
WASTE DEALER – a middleman who buys recyclable materials from waste generators and itinerant buyers and sells them, after sorting and some processing, to wholesale brokers or recycling industries.
WASTE MANAGEMENT HIERARCHY – a ranking of waste management operations according to their environmental or energy benefits. The purpose of the waste management hierarchy is to make waste management practices as environmentally sound as possible
WASTE REDUCTION – all means of reducing the amount of waste that is produced initially and that must be collected by solid waste authorities. This ranges from legislation and product design to local programs designed to keep recyclables and compostables out of the final waste stream
WASTE STREAM – the total flow of waste from a community, region, or facility.
WASTE-TO-ENERGY (WTE) PLANT – a facility that uses solid waste materials (processed or raw) to produce energy. WTE plants include incinerators that produce steam for district heating or industrial use, or that generate electricity; they also include facilities that convert landfill gas to electricity.
– Y –
YARD WASTE – leaves, grass clippings, prunings and other natural organic matter discarded from yards and gardens.
