Anaerobic digestion occurs when bacteria break down (or "digest") organic materials in the absence of oxygen.

Beneficial Use Determination is a MassDEP approval to re-use a material that is separated from waste but contains some contamination in new commercial products, to replace virgin material in a regulated facility (such as a landfill), or in applications where people might be exposed to the contaminated material.

Bottle Bill is the Massachusetts Beverage Container Recovery Law (MGL c. 94, sections 321-327)., which requires bottlers and distributors of carbonated and malted beverages to place a $0.05 deposit on every container sold to retailers (stores) in Massachusetts. Retailers collect the $0.05 deposit from their customers, for each container purchased.  When consumers return empty containers, their deposit for each is returned.

Commercial Waste is waste that is generated by businesses.  It can include discarded materials from offices, stores, warehouses, restaurants, institutions (e.g., colleges) and non-hazardous industrial waste.

Compost is the product of a controlled process of decomposing organic material. Naturally occurring soil organisms recycle nitrogen, potash, phosphorus, and other plant nutrients as they convert the material into humus.

Construction and Demolition (C&D) Waste means the waste building materials and rubble resulting from the construction, remodeling, repair or demolition of buildings, pavements, roads or other structures. Construction and demolition waste includes but is not limited to, concrete, bricks, lumber, masonry, road paving materials, rebar and plaster.

C&D Fines means C&D residuals resulting from the processing of C&D waste that have been screened or otherwise sorted to be less than three inches in size.

C&D Residuals means all materials remaining after processing C&D waste that have not been recycled or recovered and that either need disposal at a solid waste disposal facility (landfill or municipal waste combustor (MWC) or are beneficially reused at a solid waste disposal facility, for example C&D fines used as grading and shaping material or alternative daily cover

Determination of Need is a MassDEP review of a proposal to build a recycling or composting facility that will accept specific types of material that has been pre-sorted before it is sent to the facility.  This review determines whether the facility will need to obtain a Site Assignment from the municipality in which it will be located, before it can be built.

Digestion is the biological decomposition of material in a container

Disposal means the final dumping, landfilling or placement of solid waste into or on any land or water or the incineration of solid waste.

Emission means the discharge of an air contaminant into the ambient air.

Gasification is a chemical process that converts carbon-containing material, such as coal, petroleum coke, or MSW into a synthesis gas that can be used for energy production or as a building block for other chemical manufacturing process. 

Haulers are private businesses that pick up solid waste from residents and businesses, and take it to a recycling facility, transfer station or disposal facility.

Landfill means a facility or part of a facility established in accordance with a valid site assignment for the disposal of solid waste into or on land.

Leachate is water (usually from rain) that percolates through waste material in a landfill.  As the water moves through the waste, it picks up contaminants from the waste material, and it must be collected and properly disposed of, to avoid transferring the contaminants to groundwater.

Material Recovery Facility (MRF) is a facility that sorts and bales paper, glass, plastic and metal containers before selling them to industries which use the recyclables as feedstock in their manufacturing process.

Municipal Solid Waste (MSW) means trash that is discarded by residents, businesses, institutions, and municipalities. It does not include hazardous waste or industrial by-products.

Municipal Waste Combustors (MWCs) are facilities that burn municipal solid waste (commonly known as trash or garbage) at a very high temperature (approximately 2,500 degrees Fahrenheit) to generate electricity or steam power.  These facilities are also known as "waste to energy" plants and as "incinerators" (although traditionally, "incinerators" just burn trash and do not generate electricity or steam.

"Pay As You Throw" (PAYT) is a way of funding municipal solid waste collection by charging residents for each bag or barrel of trash they discard and not charging to collect recyclable material.

Processing means the use of a method, technique or process to reduce the volume or alter the physical characteristics of solid waste or of recyclable or compostable materials by separating, baling, shredding, crushing or reworking.  Processing prepares materials so they can be used in manufacturing new products or otherwise re-used.

Pyrolysis is the thermal decomposition of organic materials into gases, oils, and char. 

Recyclables are discarded materials that can be recycled.

Recycle means to recover materials or by-products which are reused; ued as an ingredient or a feedstock in an industrial or manufacturing process to make a marketable product; or ued in a particular function or application as an effective substitute for a commercial product or commodity.  "Recycle" does not mean to recover energy from the combustion of a material.

Recovery means the use, but not the disposal, of a separated material for energy production or other uses (except use at a solid waste disposal facility) when explicitly approved by MassDEP through policy, Beneficial Use Determination (BUD) or other written approval mechanism.   Also, C&D wood, but not mixed C&D, sent to a MWC is considered recovery not disposal.

Site Assignment is a municipal approval of the use of a specific property for a solid waste management facility.

Sludge is the solid material that is suspended in wastewater, and remains after wastewater has been disposed of.

Transfer Stations are facilities that receive, temporarily store, and ship loads of recyclables and solid wastes for transport to a Material Recovery Facility, recycling processor or final disposal site

Waste Bans are prohibition on the disposal of specific materials, as established in the Solid Waste Facility Regulations (310 CMR 19.017).  The bans cover materials that can be recycled, and preserve capacity at disposal facilities for materials that cannot be recycled.