Human waste (or human excreta) refers to the waste products of the

human digestive system The human digestive system consists of the gastrointestinal tract plus the accessory organs of digestion (the tongue, salivary glands, pancreas, liver, and gallbladder). Digestion involves the breakdown of food into smaller and smaller compone ...

menses Menstruation (also known as a period, among other colloquial terms) is the regular discharge of blood and mucosal tissue from the inner lining of the uterus through the vagina. The menstrual cycle is characterized by the rise and fall of horm ...

, and human

metabolism Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...

including

urine Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excretion, excreted from the body through the urethra. Cel ...

and

faeces Feces ( or faeces), known colloquially and in slang as poo and poop, are the solid or semi-solid remains of food that was not digested in the small intestine, and has been broken down by bacteria in the large intestine. Feces contain a relati ...

. As part of a

sanitation Sanitation refers to public health conditions related to clean drinking water and treatment and disposal of human excreta and sewage. Preventing human contact with feces is part of sanitation, as is hand washing with soap. Sanitation systems ...

system that is in place, human waste is collected, transported, treated and disposed of or reused by one method or another, depending on the type of

toilet A toilet is a piece of sanitary hardware that collects human urine and feces, and sometimes toilet paper, usually for disposal. Flush toilets use water, while dry or non-flush toilets do not. They can be designed for a sitting position popu ...

being used, ability by the users to pay for services and other factors. Faecal sludge management is used to deal with fecal matter collected in on-site sanitation systems such as

pit latrines A pit latrine, also known as pit toilet, is a type of toilet that collects human feces in a hole in the ground. Urine and feces enter the pit through a drop hole in the floor, which might be connected to a toilet seat or squatting pan for user ...

and

septic tanks A septic tank is an underground chamber made of concrete, fiberglass, or plastic through which domestic wastewater (sewage) flows for basic sewage treatment. Settling and anaerobic digestion processes reduce solids and organics, but the treatme ...

. The sanitation systems in place differ vastly around the world, with many people in

developing countries A developing country is a sovereign state with a lesser developed industrial base and a lower Human Development Index (HDI) relative to other countries. However, this definition is not universally agreed upon. There is also no clear agreem ...

having to resort to

open defecation Open defecation is the human practice of defecating outdoors ("in the open") rather than into a toilet. People may choose fields, bushes, forests, ditches, streets, canals, or other open spaces for defecation. They do so either because they do ...

where human waste is deposited in the environment, for lack of other options. Improvements in "

water Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a ...

and

hygiene Hygiene is a series of practices performed to preserve health. According to the World Health Organization (WHO), "Hygiene refers to conditions and practices that help to maintain health and prevent the spread of diseases." Personal hygiene refer ...

" (WASH) around the world is a key

public health Public health is "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals". Analyzing the det ...

issue within

international development International development or global development is a broad concept denoting the idea that societies and countries have differing levels of economic or human development on an international scale. It is the basis for international classifications ...

and is the focus of Sustainable Development Goal 6. People in

developed countries A developed country (or industrialized country, high-income country, more economically developed country (MEDC), advanced country) is a sovereign state that has a high quality of life, developed economy and advanced technological infrastruct ...

tend to use

flush toilets A flush toilet (also known as a flushing toilet, water closet (WC) – see also toilet names) is a toilet that disposes of human waste (principally urine and feces) by using the force of water to ''flush'' it through a drainpipe to another lo ...

where the human waste is mixed with water and transported to

sewage treatment plants Sewage treatment (or domestic wastewater treatment, municipal wastewater treatment) is a type of wastewater treatment which aims to remove contaminants from sewage to produce an effluent that is suitable for discharge to the surrounding envir ...

. Children's excreta can be disposed of in

diaper A diaper /ˈdaɪpə(r)/ (American and Canadian English) or a nappy ( Australian English, British English, and Hiberno-English) is a type of underwear that allows the wearer to urinate or defecate Defecation (or defaecation) follows dig ...

s and mixed with

municipal solid waste Municipal solid waste (MSW), commonly known as trash or garbage in the United States and rubbish in Britain, is a waste type consisting of everyday items that are discarded by the public. "Garbage" can also refer specifically to food waste, ...

. Diapers are also sometimes dumped directly into the environment, leading to

risks.

Terminology

The term "human waste" is used in the general media to mean several things, such as

sewage Sewage (or domestic sewage, domestic wastewater, municipal wastewater) is a type of wastewater that is produced by a community of people. It is typically transported through a sewer system. Sewage consists of wastewater discharged from residenc ...

sewage sludge Sewage sludge is the residual, semi-solid material that is produced as a by-product during sewage treatment of industrial or municipal wastewater. The term " septage" also refers to sludge from simple wastewater treatment but is connected to s ...

, blackwater - in fact anything that may contain some

human faeces Human feces (or faeces in British English) is the solid or semisolid remains of food that could not be digested or absorbed in the small intestine of humans, but has been further broken down by bacteria in the large intestine. It also contains ba ...

. In the stricter sense of the term, human waste is in fact human excreta, i.e.

and

, with or without water being mixed in. For example,

dry toilets A dry toilet (or non-flush toilet, no flush toilet or toilet without a flush) is a toilet which, unlike a flush toilet, does not use flush water. Dry toilets do not use water to move excreta along or block odors. They do not produce sewage, and a ...

collect human waste without the addition of water.

Health aspects

Human waste is considered a biowaste, as it is a

vector Vector most often refers to: *Euclidean vector, a quantity with a magnitude and a direction *Vector (epidemiology), an agent that carries and transmits an infectious pathogen into another living organism Vector may also refer to: Mathematic ...

for both viral and

bacterial Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...

diseases. It can be a serious health hazard if it gets into sources of drinking water. The

World Health Organization The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level of h ...

(WHO) reports that nearly 2.2 million people die annually from diseases caused by contaminated water, such as cholera or diarrhea. A major accomplishment of human civilization has been the reduction of

disease transmission In medicine, public health, and biology, transmission is the passing of a pathogen causing communicable disease from an infected host individual or group to a particular individual or group, regardless of whether the other individual was previo ...

via human waste through the practice of

and

, which can employ a variety of different technologies.

Environmental aspects

Even high-mountains are not free from human waste. Each year, millions of mountaineers visit high-mountain areas. They generate tonnes of faeces and urine annually which cause environmental pollution. Human faeces pose a greater threat to the mountain environment than uncontrolled deposit of urine, due to the higher pathogen content of faeces.

Methods of processing

Methods of processing depend on the type of human waste: * Sewage is treated via

sewage treatment Sewage treatment (or domestic wastewater treatment, municipal wastewater treatment) is a type of wastewater treatment which aims to remove contaminants from sewage to produce an effluent that is suitable for discharge to the surrounding e ...

* Sewage sludge is treated by

sewage sludge treatment Sewage sludge treatment describes the processes used to manage and dispose of sewage sludge produced during sewage treatment. Sludge treatment is focused on reducing sludge weight and volume to reduce transportation and disposal costs, and on red ...

* Fecal matter from

may undergo

composting Compost is a mixture of ingredients used as plant fertilizer and to improve soil's physical, chemical and biological properties. It is commonly prepared by decomposing plant, food waste, recycling organic materials and manure. The resulting m ...

* Fecal sludge from pit latrines is treated and managed with an approach called

fecal sludge management Fecal sludge management (FSM) (or faecal sludge management in British English) is the storage, collection, transport, treatment and safe end use or disposal of fecal sludge. Together, the collection, transport, treatment and end use of fecal slud ...

The amount of water mixed with human waste can be reduced by the use of waterless

urinal A urinal (, ) is a sanitary plumbing fixture for urination only. Urinals are often provided in public toilets for male users in Western countries (less so in Muslim countries). They are usually used in a standing position. Urinals can be ...

s and

composting toilet A composting toilet is a type of dry toilet that treats human waste by a biological process called composting. This process leads to the decomposition of organic matter and turns human waste into compost-like material. Composting is carried ou ...

s and by recycling

greywater Greywater (or grey water, sullage, also spelled gray water in the United States) refers to domestic wastewater generated in households or office buildings from streams without fecal contamination, i.e., all streams except for the wastewater from ...

. The most common method of human waste treatment in rural areas where municipal sewage systems are unavailable is the use of

septic tank A septic tank is an underground chamber made of concrete, fiberglass, or plastic through which domestic wastewater ( sewage) flows for basic sewage treatment. Settling and anaerobic digestion processes reduce solids and organics, but the treatm ...

systems. In remote rural places without sewage or septic systems, small populations allow for the continued use of honey buckets and sewage lagoons (see

anaerobic lagoon An anaerobic lagoon or manure lagoon is a man-made outdoor earthen basin filled with animal waste that undergoes anaerobic respiration as part of a system designed to manage and treat refuse created by concentrated animal feeding operations (CAFOs). ...

) without the threat of disease presented by places with denser populations. Bucket toilets are used by rural villages in

Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...

where, due to

permafrost Permafrost is ground that continuously remains below 0 °C (32 °F) for two or more years, located on land or under the ocean. Most common in the Northern Hemisphere, around 15% of the Northern Hemisphere or 11% of the global surface ...

, conventional waste treatment systems cannot be utilized.

Uses

Human waste in the form of wastewater (sewage) is used to irrigate and fertilize fields in many parts of the developing world where fresh water is unavailable. There is great potential for wastewater agriculture to produce more food for consumers in urban areas, as long as there is sufficient education about the dangers of eating such food uncooked.
Human Waste Used by 200 Million Farmers, Study Says
', National Geographic News, August 21, 2008

References