Landfilling is the final placement of waste into or onto the land in a controlled way. The definition covers both landfilling at internal sites (i.e., where a generator of waste is carrying out its own waste disposal at the place of generation) and at external sites (United Nations, 2016).

Tailings are a common by-product of the mineral recovery process. They usually take the form of a liquid slurry made of fine mineral particles (created when mined ore is crushed, ground and processed) and water (ICMM, 2019).

Waste [treatment] lagoons can be defined as impoundments made by excavation or earth fill for biological treatment of animal and other agricultural waste (Spellman and Bieber, 2012).

Disaster waste is the waste generated by the impact of a disaster, both as a direct effect of the disaster as well as in the post-disaster phase as a result of poor waste management (UNEP/OCHA, 2011).

Solid waste covers discarded materials that are no longer required by the owner or user. Solid waste includes materials that are in a solid or liquid state but excludes wastewater and small particulate matter released into the atmosphere (United Nations, 2014).

Wastewater is regarded as a combination of one or more of the following materials: domestic effluent consisting of ‘blackwater’ (excreta, urine and faecal sludge, contaminants from pharmaceutical and personal care products) and ‘greywater’ (used water from washing and bathing); water from commercial establishments and institutions, including hospitals; industrial effluent, stormwater and other urban runoff; and agricultural, horticultural and aquaculture runoff (UN Water, 2017).

Hazardous waste is waste that has physical, chemical, or biological characteristics such that it requires special handling and disposal procedures to avoid negative health effects, adverse environmental effects or both (Joint UNEP/OCHA Environment Unit, 2011).

Plastic is a generic term used in the case of polymeric material that may contain other substances to improve performance and/or reduce costs, with plastic waste almost exclusively comprising one non-halogenated polymer and waste substances or objects which are disposed of or are intended to be disposed of or are required to be disposed of by the provisions of national law (adapted from Basel Convention, 1989; and Basel Convention Secretariat, 2019).

Electrical and electronic waste, or E-waste, refers to electrical or electronic equipment that is waste, including all components, subassemblies and consumables that are part of the equipment at the time the equipment becomes waste (UNEP, 2019).

Healthcare waste includes waste generated within healthcare facilities, research centres and laboratories related to medical procedures and medical equipment. It also includes waste originating from minor and scattered healthcare sources, including waste produced in the course of emergency medical treatment or health care undertaken in the home (e.g., home dialysis, self-administration of insulin, recuperative care) (WHO, 2014).