At the end of each definition in this Glossary there is a number in brackets. This indicates the number of the Study Session where the term is first used in this OpenWASH module.

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abbreviation for reduce, reuse, recycle – a reminder of the best ways of dealing with solid waste (1)


4 Ps

factors that a marketing strategy is based on: product, place, promotion and price (13)



with oxygen; the term usually applies to microbial decomposition processes that take place where air is present (5)


ability to pay for a product or service (13)

agricultural waste

waste that comes from farming (1)


without oxygen; the term usually applies to microbial decomposition that takes place in the absence of air (5)

anaerobic digestion

decomposition of organic material by micro-organisms in the absence of oxygen to produce biogas (5)

anaerobic pond

first stage in a waste stabilisation pond system that consists of a deep pond  where anaerobic decomposition takes place (6)


a type of composting latrine that does not require emptying. When the pit is full, a tree is planted in it and a new pit is dug (5)

ash content

percentage of solid material remaining when all the combustible material in a waste has been burned (7)



simple, single-celled microscopic organisms (2)

baseline data

data collected at the start of an intervention to provide comparison for the data collected later (15)

baseline position

the situation in an area before the start of an intervention (such as the launch of a WASH programme) (3)

biochemical oxygen demand (BOD)

amount of oxygen required by micro-organisms to break down the organic material in an effluent (4)


capable of being broken down by biological processes (7)


breaking down (decomposition) of organic substances by bacteria and other micro-organisms (4)


mixture of methane (about 60%) and carbon dioxide produced by decomposition of organic material by micro-organisms (5)

biogas latrine

type of latrine where the excreta undergoes anaerobic digestion to produce biogas (5)


wastewater that contains urine and faeces (1)


calorific value

amount of heat released when something is burned (7)

chemical oxygen demand (COD)

amount of oxygen required to chemically oxidise the organic material in an effluent (4)

cistern-flush toilet

toilet with a cistern (tank) containing water used to flush wastes away; requires connection to a piped water supply (5)

closed questions

questions with a limited number of possible answers (3)


materials that can be burned (7)

commercial opportunities

ways in which private sector organisations could provide products or services on a commercial basis for profit (13)

commercial waste

solid waste produced by the commercial sector (retail, education, banking, government, etc.) (1)


devices that use blades to shred rags, paper, etc. in wastewater at a treatment works (6)

community-led total sanitation and hygiene (CLTSH)

method for mobilising communities to completely eliminate open defecation by triggering collective behaviour change and installing and using latrines, and encouraging good hygiene practices (13)

compact (solid waste)

to reduce the volume occupied by landfilled waste by drivng a tractor or other heavy vehicle over the waste (10)


soil-like substance made from decayed organic matter that is used to improve soil (5)


aerobic treatment of organic waste to produce a useful soil conditioner (8)

construction and demolition waste

solid waste from the demolition of old buildings, roads, etc., and from the construction of new ones (1)

controlled landfill

landfill site where measures are taken to reduce environmental pollution (10)


strongly acidic or alkaline substances that can dissolve many materials and destroy living tissue (10)



removal of sludge from pit latrines and septic tanks (6)


serious disruption of the functioning of society, causing widespread human, material or environmental losses (14)

disposal (of waste)

getting rid of waste that cannot be treated in any other way, usually by landfill (8)


system of perforated pipes in trenches to allow the liquid effluent from a septic tank to soak into the ground (6)


ecological sanitation (ecosan)

sanitation systems that allow the recovery of resources from the urine and faeces for use as a soil conditioner, liquid fertiliser or biogas (5)


extent to which the purpose of a programme or project has been achieved. In ISWM, it is a principle stating that a waste management system must meet the needs of the waste plan and of the local people (11)


increasing the output for a given input of resources, or minimising the input for a given output. In ISWM, it is a principle stating that the waste management system should make the best use of money, people and other resources (11)


another term for wastewater that flows out from a source (4)

electronic and electrical waste (e-waste)

waste electrical and electronic equipment and goods (1)


sudden and unforeseen event that calls for immediate action to minimise its adverse consequences (14)


allocation of resources, services and opportunity to all segments of the population according to their needs. In ISWM, it is a principle stating that everyone has a right to an effective and safe waste management service (11)


objective assessment part way through or at the end of a project to assess its design, implementation and results, and the extent to which the stated objectives have been achieved (15)


a combination of urine and faeces (1)


facilities (sanitation)

structures that are used to provide sanitation (1)

facultative ponds

waste stabilisation ponds that are aerobic at the top and anaerobic at the bottom (6)

faecal-oral route

transmission of pathogens from human faeces to a person via the mouth (2)

faecal sludge management

set of processes including storage, collection, transport, treatment and safe end-use or disposal of faecal sludge (6)

F diagram

diagram that shows the pathways for human exposure to pathogens through the faecal-oral route (2)

focus group

small group of people who discuss an issue relating to them in an organised session with a facilitator/moderator (3)


grease trap

a small tank within an outlet pipe that slows the flow of effluent so that oils and fat float to the surface and can be removed (4)

greenhouse gases

gases such as carbon dioxide and methane that contribute to human-induced climate change (2)


wastewater from washing, cooking and clothes washing (1)


very small pieces of sand, stone and possibly glass and metal found in wastewater (6)



something with the potential to cause harm, such as toxic chemicals or infectious material (1)

hazardous wastes

wastes that have the potential to cause substantial harm to public health and/or the environment (7)

healthcare waste

solid waste produced in health facilities (1)

heavy metals

group of toxic chemical pollutants that persist in the environment i.e. they do not break down by natural processes e.g. mercury, lead, cadmium, nickel, chromium and others (4)


worms that live as parasites in humans and other animals (2)

household hazardous waste

hazardous materials such as cleaning products, batteries and paint found in household waste (10)

household waste

solid waste produced by people in their homes; also known as ‘residential waste’ (1)


set of practices that help to keep people healthy and prevent the spread of disease (2)


ignitable (waste)

solid and liquid wastes that start to burn easily when exposed to a flame or any other source of ignition (10)

impact evaluation

identifying  the effects on individuals,  households or communities caused by implementing a project or programme (15)


long-term effects and consequences of project or programme outcomes (15)


does not allow fluid to pass through (6)

improved facilities (sanitation)

sanitation facilities that ensure the separation of faeces from people (1)


treatment of waste by burning under controlled conditions (10)

in-depth interview

detailed interview on a particular subject (3)


something that can be seen, measured or counted and provides evidence of progress towards a target (15)

industrial waste

solid waste produced by industrial organisations (1)


not derived from living organisms (4)

Integrated Solid Waste Management (ISWM)

using a combination of techniques and technologies to treat waste in the way that is best for people's health and the environment (11)

internally displaced people (IDP)

people who are forced to leave their homes in the event of an emergency and move to another location within their own country (14)


key performance indicators (KPIs)

measures of inputs, processes, outputs, outcomes and impacts for programmes or strategies that have been identified as the most significant (15)


people who collect recyclable wastes from individual households as part of the informal waste management sector (8)



area of land set aside for the final disposal of solid waste (1)

landfill gas

gas that forms in landfills as the waste decomposes – mainly a mixture of carbon dioxide and methane (10)


polluted water that emerges at the base of landfilled waste (10)

liquid waste

any waste in a liquid or semi-solid form, including human waste and all types of wastewater (1)


management information system (MIS)

computer-based data collection and analysis system (15)

maturation pond

the final stage of a waste stabilisation pond system, where pathogenic viruses and bacteria are removed and eggs of parasitic worms settle out in the sludge (6)

mechanical biological system

system for treating sewage using a sequence of mechanical (such as aeration) and biological processes (6)

menstrual hygiene management (MHM)

provision of facilities to allow girls and women to manage their monthly menstrual periods, including materials to absorb or collect menstrual blood, private places to change and clean/dispose of these materials, and handwashing facilities with soap (12)


a flammable gas produced during anaerobic decomposition processes; a powerful greenhouse gas (7)

moisture content

percentage of water in a solid substance (7)


systematic and continuous assessment of the progress of a project or programme over time, in order to check that activities are going to plan (15)


illness (2)


death (2)

MSEs (micro and small enterprises)

small businesses with fewer than 50 employees (9)

municipal waste (municipal solid waste)

combination of all the solid wastes produced in urban areas; similar in composition to residential waste (1)



not capable of undergoing biological decomposition (7)


materials that do not burn (7)

non-hazardous wastes

waste that is not classed as hazardous (although note that these wastes can still be harmful) (7)


objective (assessment)

assessment based solely on observations, measurements, etc. and not influenced by the personal feelings and opinions of the assessor (3)


assessment based on what the investigator sees and experiences when visiting the area (3)

open burning

burning waste in a uncontrolled way in the open air (10)

open defecation

the practice of defecating (excreting faeces) in the open and not in a latrine (1)

open dumping

uncontrolled disposal of solid waste in open spaces such as waste ground, roadsides and riverbanks (10)

open questions

questions that allow the respondent to say whatever they wish (3)


derived from living organisms (4)

outcome evaluation

assessment of what a project or programme has achieved in the short to medium term (15)


effects of a project or programme, usually in the short to medium term (15)


things produced or objectives achieved by a project or programme (15)


parasitic worms

group of parasites such as tapeworms or nematodes (also known as roundworms); helminthes (2)


disease-causing agent (1)

peri-urban areas

areas around a town or city between the urban and rural areas and having some characteristics of both (2)


measure of acidity and alkalinity. It has a scale from 0 to 14: pH 7 is neutral, less than 7 is acid and more than 7 is alkaline (6)

placenta pit

pit in a hospital or healthcare centre grounds for disposal of anatomical and pathological waste (placentas, body parts, blood, body fluids) (12)

polluting potential

potential of wastewaters to cause pollution, i.e. to cause damage to the condition, health, safety or welfare of animals, humans, plants or property (4)


introduction into the environment of substances liable to cause harm (1)

pour-flush toilet

toilet where the urine and faeces are flushed away by pouring water from a jug down the toilet after use (5)

primary collection

collection of waste from individual households and businesses or from communal bins serving a number of households (9)

primary treatment

first stage of the sewage treatment process where most solids are removed by sedimentation (6)

private sector participation

involving the private sector (in waste management) (9)

process evaluation

assessment of the ways a project or programme has been undertaken to determine whether it is on track to meet its aims (15)


single-celled microscopic organisms, larger than bacteria (2)

public-private partnership

collaboration between a public sector body or organisation and a private sector company (9)


qualitative data

information collected about views and opinions (15)

quantitative data

measurable, factual data (15)


a set of questions that people are asked to answer as part of an assessment (3)


rapid-onset disaster

disaster resulting from a unique, distinct and unforeseeable event, such as a flood (14)

reactive (waste)

wastes that react rapidly with air or water, or are explosive (10)

recovery (of waste)

finding other uses for wastes that enable some value to be extracted or recovered from them (8)


processing wastes to allow them to be manufactured into new materials and goods (1)

reduction (of waste)

avoiding the production of solid waste (1)

reed bed

artifically constructed wetland with reeds planted in it for wastewater treatment (6)

replacement (of hazardous waste)

replacing a hazardous material with a non-hazardous one during manufacturing, or changing a process so that it does not produce waste products that are hazardous (10)

residential waste

solid waste from households and other residential areas (1)

retention time

length of time that wastewater spends (is retained) in a septic tank, pond, etc. (6)


using a waste item for its original purpose more than once (1)


sanitary landfill

an advanced landfill with engineering measures to prevent the escape of leachate and collect the landfill gas (10)


prevention of human contact with wastes; the provision of facilities and services for the safe disposal of human excreta (1)

sanitation ladder

measure of progress towards the provision of adequate sanitation facilities for every household (1)

sanitation marketing

an approach to household sanitation promotion that aims to improve sanitation standards by encouraging people’s demand for sanitation products and services (13)

sanitation platform

cast concrete or plastic latrine slab that is safe for children and convenient for adults, and has footrests (5)

secondary collection

collection of solid waste from transfer stations for transport to the final disposal site (9)

secondary treatment

stage in sewage treatment where aerobic micro-organisms break down organic material (6)

semi-structured interview

an interview with a set of topics and questions for discussion that develops according to responses given (3)

septic tank

underground, watertight tank in which sewage is collected and partially treated before discharge (5)

services (sanitation)

the entire scheme for providing sanitation (facilities, maintenance, waste treatment, finance) (1)

settleable solids

solid particles in wastewaters that settle out when the flow rate is reduced (4)


combined wastewater from all sources; includes blackwater, greywater and stormwater (1)


underground pipes that carry sewage; ditches containing sewage may be described as open sewers (4)


network or system of sewers (4)

shared sanitation facilities

latrine used by more than one family/household (1)

slow-onset disaster

disaster that unfolds over time as a result of events, such as drought and famine (14)

Sludge Gulper

type of hand-operated pump for desludging pit latrines (6)


pit where liquid effluent, typically from a septic tank, is allowed to soak into the ground

soil improver

product such as compost that makes soil more productive and resistant to drought (8)

solid waste

all the discarded solid wastes arising from human activities (1)


an individual, organisation or group that has an interest in something, e.g. a situation, project, process or activity (11)


rainwater that collects on the ground and runs off into channels, ditches and rivers and may carry pollutants with it (1)

structured interview

interview based only on a set of questions drawn up before the start (3)

subjective (assessment)

assessment based on the investigator’s personal experience and views, which will vary between individuals (3)


another term for greywater (1)

suspended solids

solid particles in wastewaters that do not settle out when the liquid is left to stand; in flowing water, this includes solids that are carried in the flow (4)


concept describing effective and long-lasting projects and other interventions that have given consideration to economic, social and environmental factors. In ISWM, it is a principle stating that the waste management system must be capable of operating in the long term, mimimising the use of non-renewable resources and not causing pollution problems that will need to be dealt with by future generations (11)

sustainable drainage systems (SuDS)

range of techniques to reduce the speed of flow of surface run-off, encourage its infiltration into the ground, and reduce the risk of flooding (6)


transfer station

place where waste from primary collections is combined and transferred to a vehicle for transport to the final disposal site (9)


unimproved facilities (sanitation)

sanitation facilities that do not ensure the separation of faeces from people (1)


increase in the number of people living in towns and cities relative to rural areas (1)

urine diverting latrine

type of latrine that separates urine and faeces, allowing the recovery of two products (5)



type of small, mobile device for removing and transporting sludge from pit latrines (6)


animals that can be responsible for spread of diseases e.g. mosquitoes, flies, rats(2)

ventilated improved pit (VIP) latrine

type of latrine fitted with a vent pipe to provide a natural ventilation system that reduces odours and fly nuisance (5)


infectious agents that are not living organisms but are able to invade cells and cause them to manufacture more virus material (2)



substances or objects that no longer have a use and are disposed of (1)

waste hierarchy

a guide to the best ways of treating solid waste that ranks them in order of preference (1)

waste management

collection, treatment and disposal of solid waste (1)

waste stabilisation ponds

series of ponds where natural biological and physical processes remove pollutants from wastewater (6)

willingness to pay

extent to which people are motivated to pay for improved sanitation and waste management (13)

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