Toilet
.jpg)
A toilet[n 1] is a piece of sanitary hardware (sanitaryware) 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 position popular in Europe and North America with a toilet seat, with additional considerations for those with disabilities, or for a squatting posture more popular in Asia, known as a squat toilet. In urban areas, flush toilets are usually connected to a sewer system; in isolated areas, to a septic tank. The waste is known as blackwater and the combined effluent, including other sources, is sewage. Dry toilets are connected to a pit, removable container, composting chamber, or other storage and treatment device, including urine diversion with a urine-diverting toilet. "Toilet" or "toilets" is also widely used for rooms containing only one or more toilets and hand-basins. Lavatory is an older word for toilet.
The technology used for modern toilets varies. Toilets are commonly made of ceramic (porcelain), concrete, plastic, or wood. Newer toilet technologies include dual flushing, low flushing, toilet seat warming, self-cleaning, female urinals and waterless urinals. Japan is known for its toilet technology. Airplane toilets are specially designed to operate in the air. The need to maintain anal hygiene post-defecation is universally recognized and toilet paper (often held by a toilet roll holder), which may also be used to wipe the vulva after urination, is widely used (as well as bidets).
In private homes, depending on the region and style, the toilet may exist in the same bathroom as the sink, bathtub, and shower. Another option is to have one room for body washing (also called "bathroom") and a separate one for the toilet and handwashing sink (toilet room). Public toilets (restrooms) consist of one or more toilets (and commonly single urinals or trough urinals) which are available for use by the general public. Products like urinal blocks and toilet blocks help maintain the smell and cleanliness of toilets. Toilet seat covers are sometimes used. Portable toilets (frequently chemical "porta johns") may be brought in for large and temporary gatherings.
Historically, sanitation has been a concern from the earliest stages of human settlements. However, many poor households in developing countries use very basic, and often unhygienic, toilets – and 419 million people have no access to a toilet at all; they must openly defecate and urinate.[1] These issues can lead to the spread of diseases transmitted via the fecal-oral route, or the transmission of waterborne diseases such as cholera and dysentery. Therefore, the United Nations Sustainable Development Goal 6 wants to "achieve access to adequate and equitable sanitation and hygiene for all and end open defecation".[2]
Overview
The number of different types of toilets used worldwide is large,[3][4] but can be grouped by:
- Having water (which seals in odor) or not (which usually relates to e.g. flush toilet versus dry toilet)
- Being used in a sitting or squatting position (sitting toilet versus squat toilet)
- Being located in the private household or in public (toilet room versus public toilet)
Toilets can be designed to be used in standing, sitting, or squatting postures. Each type has its benefits. The "sitting toilet", however, is essential for those who are movement impaired. Sitting toilets are often referred to as "western-style toilets".[5] Sitting toilets are more convenient than squat toilets for people with disabilities and the elderly.
People use different toilet types based on the country that they are in. In developing countries, access to toilets is also related to people's socio-economic status. Poor people in low-income countries often have no toilets at all and resort to open defecation instead. This is part of the sanitation crisis which international initiatives (such as World Toilet Day) draw attention to.[6]
With water
Flush toilet
A typical flush toilet is a ceramic bowl (pan) connected on the "up" side to a cistern (tank) that enables rapid filling with water, and on the "down" side to a drain pipe that removes the effluent. When a toilet is flushed, the sewage should flow into a septic tank or into a system connected to a sewage treatment plant. However, in many developing countries, this treatment step does not take place.
The water in the toilet bowl is connected to a pipe shaped like an upside-down U. One side of the U channel is arranged as a siphon tube longer than the water in the bowl is high. The siphon tube connects to the drain. The bottom of the drain pipe limits the height of the water in the bowl before it flows down the drain. The water in the bowl acts as a barrier to sewer gas entering the building. Sewer gas escapes through a vent pipe attached to the sewer line.
The amount of water used by conventional flush toilets usually makes up a significant portion of personal daily water usage.[7] However, modern low flush toilet designs allow the use of much less water per flush. Dual flush toilets allow the user to select between a flush for urine or feces, saving a significant amount of water over conventional units. One type of dual flush system allows the flush handle to be pushed up for one kind of flush and down for the other,[8] whereas another design is to have two buttons, one for urination and the other for defecation. In some places, users are encouraged not to flush after urination. Flushing toilets can be plumbed to use greywater (water that was previously used for washing dishes, laundry, and bathing) rather than potable water (drinking water). Some modern toilets pressurize the water in the tank, which initiates flushing action with less water usage. Flush toilets on boats and ships (called the head) may be flushed with seawater or fresh water.[9][10]
Another variant is the pour-flush toilet.[3] This type of flush toilet has no cistern but is flushed manually with a few liters of a small bucket. The flushing can use as little as 2–3 litres (0.44–0.66 imp gal; 0.53–0.79 US gal).[3] This type of toilet is common in many Asian countries. The
toilet can be connected to one or two pits, in which case it is called a "pour flush pit latrine" or a "twin pit pour flush to pit latrine". It can also be connected to a septic tank.[11]
Twin pit designs
Twin pit latrines use two pits used alternatively, when one pit gets full over a few months or years.[12] The pits are of an adequate size to accommodate a volume of waste generated over one or two years. This allows the contents of the full pit enough time to transform into a partially sanitized, soil-like material that can be manually excavated.[13] There is a risk of groundwater pollution when pits are located in areas with a high or variable water table, and/or fissures or cracks in the bedrock.[13]
Vacuum toilet
A vacuum toilet is a flush toilet that is connected to a vacuum sewer system, and removes waste by suction. They may use very little water (less than a quarter of a liter per flush)[14] or none,[15] (as in waterless urinals). Some flush with coloured disinfectant solution rather than with water.[14] They may be used to separate blackwater and greywater, and process them separately[16] (for instance, the fairly dry blackwater can be used for biogas production, or in a composting toilet).
Passenger train toilets, aircraft lavatories, bus toilets, and ships with plumbing often use vacuum toilets. The lower water usage saves weight, and avoids water slopping out of the toilet bowl in motion.[17] Aboard vehicles, a portable collection chamber is used; if it is filled by positive pressure from an intermediate vacuum chamber, it need not be kept under vacuum.[18]
Floating toilet
A floating toilet is essentially a toilet on a platform built above or floating on the water. Instead of excreta going into the ground they are collected in a tank or barrel. To reduce the amount of excreta that needs to hauled to shore, many use urine diversion. The floating toilet was developed for residents without quick access to land or connection to a sewer systems.[19] It is also used in areas subjected to prolonged flooding.[20] The need for this type of toilet is high in areas like Cambodia.[21]
Without water
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.[22] Dry toilets do not use water to move excreta along or block odors.[23] They do not produce sewage, and are not connected to a sewer system or septic tank. Instead, excreta falls through a drop hole.[22]
Pit latrine
A pit latrine, also known as pit toilet, is a type of toilet that collects human waste in a hole in the ground.[24] 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 comfort.[24] Pit latrines can be built to function without water (dry toilet) or they can have a water seal (pour-flush pit latrine).[25] When properly built and maintained, pit latrines can decrease the spread of disease by reducing the amount of human feces in the environment from open defecation.[26][27] This decreases the transfer of pathogens between feces and food by flies.[26] These pathogens are major causes of infectious diarrhea and intestinal worm infections.[27] Infectious diarrhea resulted in about 700,000 deaths in children under five years old in 2011 and 250 million lost school days.[27][28] Pit latrines are a low-cost method of separating feces from people.[26]
Vault toilet
A vault toilet is a non-flush toilet with a sealed container (or vault) buried in the ground to receive the excreta, all of which is contained underground until it is removed by pumping. A vault toilet is distinguished from a pit latrine because the waste accumulates in the vault instead of seeping into the underlying soil.
Urine-diverting toilet
A urine-diverting dry toilet (UDDT) is a type of dry toilet with urine diversion that can be used to provide safe, affordable sanitation in a variety of contexts worldwide. The separate collection of feces and urine without any flush water has many advantages, such as odor-free operation and pathogen reduction by drying. While dried feces and urine harvested from UDDTs can be and routinely are used in agriculture (respectively, as a soil amendment and nutrient-rich fertilizer—this practice being known as reuse of excreta in agriculture), many UDDT installations do not apply any sort of recovery scheme. The UDDT is an example of a technology that can be used to achieve a sustainable sanitation system. This dry excreta management system (or "dry sanitation" system) is an alternative to pit latrines and flush toilets, especially where water is scarce, a connection to a sewer system and centralized wastewater treatment plant is not feasible or desired, fertilizer and soil conditioner are needed for agriculture, or groundwater pollution should be minimized.
Portable toilet
A portable or mobile toilet (colloquial terms: thunderbox, porta-john, porta-potty or porta-loo) is any type of toilet that can be moved around, some by one person, some by mechanical equipment such as a truck and crane. Most types do not require any pre-existing services or infrastructure, such as sewerage, and are completely self-contained. The portable toilet is used in a variety of situations, for example in urban slums of developing countries, at festivals, for camping, on boats, on construction sites, and at film locations and large outdoor gatherings where there are no other facilities. Most portable toilets are unisex single units with privacy ensured by a simple lock on the door. Some portable toilets are small molded plastic or fiberglass portable rooms with a lockable door and a receptacle to catch the human excreta in a container.
Chemical toilet
A chemical toilet collects human waste in a holding tank and uses chemicals to minimize odors. They do not require a connection to a water supply and are used in a wide variety of situations. These toilets are usually, but not always, self-contained and movable. A chemical toilet is structured around a relatively small tank, which requires frequent emptying. It is not connected to a hole in the ground (like a pit latrine), nor to a septic tank, nor is it plumbed into a municipal system leading to a sewage treatment plant.[29] When the tank is emptied, the contents are usually pumped into a sanitary sewer or directly to a treatment plant.
The enclosed portable toilets used on construction sites and at large gatherings such as music festivals are well-known types of chemical toilets. As they are usually used for short periods and because of their high prices, they are mostly rented rather than bought, often including servicing and cleaning.[30]
Toilet fed to animals
The pig toilet, which consists of a toilet linked to a pigsty by a chute, is still in use to a limited extent.[31] It was common in rural China, and was known in Japan, Korea, and India. The fish pond toilet depends on the same principle, of livestock (often carp) eating human excreta directly.
"Flying toilet"
A flying toilet is a facetious name for a plastic bag that is used as a simple collection device for human faeces when there is a lack of proper toilets and people are forced to practise open defecation. The filled and tied plastic bags are then discarded in ditches or on the roadside. Associated especially with slums, they are called flying toilets "because when you have filled them, you throw them as far away as you can".[32]