Glossary of Landfill Terms

Adverse Effect: Refers to one or more of the following:
• impairment of the quality of the natural environment for any use that can be made of it,
• injury or damage to property or to plant or animal life,
• harm or material discomfort to any person,
• an adverse effect on the health of any person,
• impairment of the safety of any person,
• rendering any property or plant or animal life unfit for human use,
• loss of enjoyment of normal use of property, and
• interference with the normal conduct of business.

Aerobic Treatment: The process by which microbes decompose complex organic compounds in the presence of oxygen 

Air Emission Monitoring: Required testing to ensure air emissions do not exceed provincial standards.

Approved Waste Types: The Certificate of Approval specifies the types of waste the landfill is approved to receive

Aquifer: A geological formation, group of formations, or portion of a formation capable of yielding significant quantities of groundwater to springs or wells.

Asbestos Waste: Solid or liquid waste that results from the removal of asbestos-containing construction or insulation materials or the manufacture of asbestos-containing products.

Backfill: The material used for, or the act of, refilling an excavation.

Bedrock: The contiguous layers of rock lying below the ground surface (i.e., not including individual stones or boulders entrained in soils).

Berm: In a landfilling site/facility, a narrow elevated earthen mound or ridge (e.g., a screening berm surrounding the waste deposit area).

Biological Treatment: A treatment technology that uses bacteria to consume organic fraction of municipal solid waste/wastewater.

BOD (Biochemical Oxygen Demand): Indicator of waterbody contamination that analyses the rate at which oxygen is consumed. The higher the number, the more contamination there is in the water. Expressed in milligrammes per litre.

Borehole: A hole drilled or pounded into the earth that is used to determine soil, rock, and/or groundwater characteristics. A borehole can be used as a potable drinking water well, or as a groundwater observation/monitoring well. Also used as a means of venting or withdrawing gas from landfills.

Brownfield Soils: Brownfields are usually former industrial lands that are now vacant or underused but have the potential to be redeveloped for new uses. Brownfields may be contaminated due to past or present activities. Some examples are:
• closed factories
• gas stations
• waterfront lands formerly used for commercial port operations

Buffer Area: The part of a landfilling site that is not a waste fill area, usually around the perimeter of the waste fill area.

Cell: Landfills are constructed in phases called cells that adjoin one another, separated by a berm to contain leachate within an area. The entire permitted area of the landfill site is divided into separate cells for construction.

Certificate of Approval (CofA): A control document issued by the Ministry of the Environment that contains specific terms and conditions for operating a landfill site to ensure the protection of human health and the environment, as per Section 27 of the Environmental Protection Act

Closure: the construction of a final cover for a landfill including the placement of a compacted soil layer that may or may not include a man-made material over the waste surface, topsoil and other materials as may be required, surface vegetation and means to control emissions of landfill gas to the atmosphere. 

Combustible Gas: In a landfill, gases produced by the decomposition of waste that will burn if ignited; methane gas is generally the major combustible constituent in landfill gas.

Composite Liner: A landfill liner consisting of both an engineered soil layer(s) and a synthetic membrane(s).

Construction & Demolition (C&D) Waste: Solid waste produced in the course of residential, commercial, industrial, or institutional building construction, demolition or renovation (e.g., lumber, concrete, brick, plaster, glass, stone, drywall, wire, paint, etc.).

Contaminant Attenuation Zone (CAZ): As defined in O. Reg. 232, contaminant attenuation zone refers to a three-dimensional area that:
• is located on land adjacent to a landfill site;
• is in the subsurface or extends into the subsurface; and
• is used or is intended to be used to reduce contaminants from the landfill site to levels that will have no adverse impact beyond the boundary of the zone

Contaminant: Any solid, liquid, gas, odour, heat, sound, vibration, radiation or combination of any of these, resulting directly or indirectly from human activities that may cause an adverse effect.

Cover Material: Soil used to cover compacted solid waste in a sanitary landfill

Daily Cover: Soil or other approved materials placed on top of landfilled wastes, on daily basis.

Design and Operation (D&O) Report: A document (plan/report), required for obtaining an Environmental Compliance Approval which describes in detail the function, elements or features of a waste management site/facility, and how it functions including its monitoring, and control/management systems.

Design Capacity: The total volume of waste that has been calculated as having the potential to be disposed of at a landfill site for a particular engineering design, typically measured in cubic metres

Double Composite Liner: A landfill liner system that uses synthetic and natural soil liners to prevent groundwater contamination. Two liners of each type are used, and each liner has several layers.

Effluent: A liquid discharged into a municipal sewer, surface water body or onto the surface of the land.

Environmental Assessment (EA): A systematic process that is conducted in accordance with applicable laws or regulations aimed at assessing the effects of a proposal on the environment. Can include the evaluation of need, alternatives, impacts, and mitigative, remedial, monitoring and/or compensatory measures.

Fill Area: The area in a landfill site where wastes are deposited. 

Fill Rate: Approved rate of waste accepted into the site, expressed on a daily operating basis or annual basis (usually in tonnes)

Fill: Earth, sand, gravel, construction rubble, waste or any other material, originating on-site or off-site, moved and placed in a new location.

Footprint:  The land area covered by a waste management facility; landfill footprint refers to the area. Total Site Area and the Fill Area.

Gas Collection System: Part(s) of the landfill site designed to capture and convey landfill gas; typically consists of drainage stone and/or pipes within, beneath or around the perimeter of the waste.

Groundwater Monitoring: Required testing of groundwater wells to determine whether waste materials have escaped from the landfill.

Groundwater: Water occurring below the ground surface contained in the pore spaces or other openings in soil or rock.

Landfill Gas Management (Energy Generation): Landfill gas is converted to electricity, usually in a specially-designed landfill gas-to-energy facility. Methane gas is used as fuel in generators to produce energy in the form of steam, electricity and heat.

Landfill Gas Management (Flaring): Landfill gas is 'flared' or thermally destroyed, usually in a specially-designed flaring facility.

Landfill Gas Management (Passive): Gas by-products i.e., methane and carbon dioxide are controlled or diverted via barriers and gas conduction systems that vent the gas through natural gas pressure from the landfill into the atmosphere.

Landfill Gas Monitoring: Gases released from landfills are electronically monitored

Landfill: An approved, engineered site/facility used for the long-term or permanent disposal of waste.

Leachate Collection System: Part(s) of a landfill site designed to capture and convey leachate; typically consists of drainage stone and/or pipes beneath or around the perimeter of the waste. 

Leachate Off-Site Treatment: Liquid that drains or 'leaches' from a landfill that is treated outside the landfill’s boundaries.

Leachate On-Site Treatment: Liquid that drains or 'leaches' from a landfill that is treated within the landfill’s boundaries

Leachate: The liquid produced when water passes through wastes and picks up contaminants.

Liner: a continuous layer constructed of natural and man-made materials, beneath or on the sides of a landfill or a cell, which restricts the downward or lateral migration of the leachate.

MSW: Municipal Solid Waste: Waste consisting of everyday items, mainly food wastes, yard wastes, containers and product packaging, and other miscellaneous wastes from residential, commercial, institutional and industrial sources.

Open landfill: A landfill that currently receives waste and operates under the terms and conditions of a Certificate of Approval

Overburden: The surface soils which rest on bedrock.

Service Area: Geographic areas of the province approved to ship wastes to the site as specified in the Certificate of Approval

Surface Water Monitoring: Required testing to ensure leachate has not contaminated the surface water

Surface Water: Water lying on, or flowing across, the land surface; includes lakes, rivers, ditches, wetlands.

Terms of Reference: A document prepared by the proponent and submitted to the Ministry of the Environment for approval. The terms of reference sets out the framework for the planning and decision-making process to be followed by the proponent during the preparation of an environmental assessment. In other words, it is the proponent’s work plan for what is going to be studied. If approved, the environmental assessment must be prepared according to the terms of reference.

Tipping Face: Unloading area for vehicles that are delivering waste to a landfill.

Tipping Fee: The charge for unloading waste at a landfill, transfer station, recycling center, or waste-to energy facility, usually in dollars per tonne.

Total Approved Capacity: Total approved capacity for the site (in cubic metres); includes any amended expansions beyond the original approval

Total Site Area: Total approved area designated as a landfill site including buffers, footprint, access roads and other site infrastructure not including a Contaminant Attenuation Zone (CAZ)

Vectors: Disease-carrying flying organisms such as insects, birds.

Zero Waste: The concept of minimizing the amount of waste that one produces. To consumers, it means maximizing recycling efforts and wasting less. To waste collection and recycling service providers, it means finding and using the most cost effective and environmentally sound methods for collecting, processing, marketing and disposing of society's wastes.


This Glossary of Landfill Terms is adapted from a variety of sources including: Information supplied by Walker Industries, Ontario Ministry of the Environment  Allied Waste Garbage Glossary, Urban Solid Waste Management and others, and is intended for general information purposes. Every attempt was made to present this with as much accuracy as possible. Any discrepancies are non-intentional.