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 Mucous membrane, mucosal tissue from the endometrium, inner lining of the uterus through the vagina. The menstrual cycle is characterized ...

, and human

metabolism Metabolism (, from ''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 cellular processes; the co ...

including

urine Urine is a liquid by-product of metabolism in humans and many other animals. In placental mammals, urine flows from the Kidney (vertebrates), kidneys through the ureters to the urinary bladder and exits the urethra through the penile meatus (mal ...

and

feces Feces (also known as faeces American and British English spelling differences#ae and oe, or fæces; : faex) 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 ...

. 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 waste (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 p ...

being used, ability by the users to pay for services and other factors.

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 ...

is used to deal with fecal matter collected in on-site sanitation systems such as pit latrines 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 treatment ...

. 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 less-developed Secondary sector of the economy, industrial base and a lower Human Development Index (HDI) relative to developed countries. However, this definition is not universally agreed upon. ...

having to resort to

open defecation Open defecation is the human practice of defecating outside ("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 is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...

and

hygiene Hygiene is a set 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 de ...

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 development, economic or human development (economics), human development on an international sca ...

and is the focus of

Sustainable Development Goal 6 Sustainable Development Goal 6 (SDG 6 or Global Goal 6) declares the importance of achieving "clean water and sanitation for all". It is one of the 17 Sustainable Development Goals established by the United Nations General Assembly to succeed the ...

. People in

developed countries A developed country, or advanced country, is a sovereign state that has a high quality of life, developed economy, and advanced technological infrastructure relative to other less industrialized nations. Most commonly, the criteria for eval ...

tend to use flush toilets where the human waste is mixed with water and transported to

sewage treatment plants Sewage treatment is a type of wastewater treatment which aims to remove contaminants from sewage to produce an effluent that is suitable to discharge to the surrounding environment or an intended reuse application, thereby preventing water ...

. Children's excreta can be disposed of in

diaper A diaper (, North American English) or a nappy (British English, Australian English, Hiberno-English) is a type of underwear that allows the wearer to urinate or defecate without using a toilet, by absorbing or containing waste products to p ...

s and mixed with

municipal solid waste Municipal solid waste (MSW), commonly known as trash or garbage in the American English, United States and rubbish in British English, Britain, is a List of waste types, waste type consisting of everyday items that are discarded by the public. ...

. 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 sewerage, sewer system. Sewage consists of wastewater discharged fro ...

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 si ...

, blackwater - in fact anything that may contain some

human feces Human feces (American English) or faeces (British English), commonly and in medical literature more often called stool, are the solid or semisolid remains of food that could not be digested or absorbed in the small intestine of humans, but has b ...

. 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 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 * Disease vector, an agent that carries and transmits an infectious pathogen into another living organism Vector may also refer to: Mathematics a ...

for both viral and

bacterial Bacteria (; : 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 the ...

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 list of specialized agencies of the United Nations, specialized agency of the United Nations which coordinates responses to international public health issues and emergencies. It is headquartered in Gen ...

(WHO) reports that nearly 2.2 million people die annually from diseases caused by contaminated water, such as cholera or dysentery. 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 tons of feces and urine annually which cause environmental pollution. Human feces pose a greater threat to the mountain environment than uncontrolled deposit of urine, due to the higher pathogen content of feces.

Methods of processing

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

sewage treatment Sewage treatment is a type of wastewater treatment which aims to remove contaminants from sewage to produce an effluent that is suitable to discharge to the surrounding environment or an intended reuse application, thereby preventing water p ...

* Sewage sludge is treated by sewage sludge treatment * Fecal matter from dry toilets 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 Decomposition, decomposing plant and food waste, recycling organic materials, and man ...

* 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 similar to a toilet, but for urination only. Urinals are often provided in men's public restrooms in Western countries (less so in Muslim countries). They are usually used in a standing position. ...

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 out b ...

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 fro ...

. 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 treatment ...

systems. In remote rural places without sewage or septic systems, small populations allow for the continued use of

honey bucket Honey bucket may refer to: Sanitation systems Different sorts of toilets, for example: * Bucket toilet * Chemical toilet, a toilet which collects human excreta in a container and uses chemicals to minimize odors * Portable toilet, a movable toilet ...

s 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 (CAFO ...

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

Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...

where, due to

permafrost Permafrost () is soil or underwater sediment which continuously remains below for two years or more; the oldest permafrost has been continuously frozen for around 700,000 years. Whilst the shallowest permafrost has a vertical extent of below ...

, 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