Urine diversion

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Cleaning a urine-diverting dry toilet (UDDT) in Johannesburg, South Africa Cleaning a urine-diverting dry toilet (UDDT) in Johannesburg (2947142348).jpg
Cleaning a urine-diverting dry toilet (UDDT) in Johannesburg, South Africa
Urine diverting flush toilet at a household in Stockholm, Sweden (company: Dubbletten) Urine diverting flush toilet in Stockholm (Dubbletten).jpg
Urine diverting flush toilet at a household in Stockholm, Sweden (company: Dubbletten)

Urine diversion, also called urine separation or source separation, refers to the separate collection of human urine and feces at the point of their production, i.e. at the toilet or urinal . Separation of urine from feces allows human waste to be treated separately and used as a potential resource. [1] :9 Applications are typically found where connection to a sewer-based sanitation system is not available or areas where water supplies are limited.

Contents

To achieve urine diversion, the following technical components are used: waterless urinals, urine diversion toilets, urine piping to a urine storage tank (or to a sewer) and a reuse or treatment and disposal system for the urine. Urine diversion toilets may, or may not, mix water and feces, or some water and urine. They never mix urine and feces.

A toilet used to facilitate the separation of human waste products is called a urine diversion toilet or UDT. The bowl usually has two separate receptacles which may or may not be flushed with water. If flushed, the toilet is usually referred to as a urine-diversion flush toilet or UDFT. If not flushed, it is a dry toilet with either drying or composting for the feces. If the collected feces are dried, it is called a urine-diverting dry toilet or UDDT (also called urine-diversion dehydration toilet). [2] If the collected feces are composted, it is called a urine-diverting composting toilet.

There are several commercially available urine diversion toilets (UDT) and urine diversion dry toilets (UDDT). Many look like a conventional sit-down or squat toilet and the bowl is divided into two sections, with the front section collecting urine and the rear section feces.

Design considerations

Purpose

There are two main reasons why urine diversion is sensible which are relevant for all types of UD systems: [1] Firstly, less water is used; secondly, the urine can be collected pure. It can then in a later step (after simple treatment, namely by storage) be used as fertilizer.

In addition, reasons for keeping urine and feces separate in a dry toilet compared to a pit latrine can be to: [2] :8

Principle

Squatting pan of urine-diverting dry toilet (UDDT) in Ouagadougou, Burkina Faso Squatting pan of urine diversion dehydration toilet (UDDT) (2957045329).jpg
Squatting pan of urine-diverting dry toilet (UDDT) in Ouagadougou, Burkina Faso

Urine diversion takes advantage of the anatomy of the human body, which excretes urine and feces separately. [2] In a UDDT, the urine is drained via a basin with a small hole near the front of the user interface, while feces fall through a larger drop-hole at the rear. This separate collection – or ‘source separation’ – does not require the user to change positions between urinating and defecating, although some care is needed to ensure the right position over the user interface.

Separate treatment of the two types of waste is justified since urine is nearly sterile and low in pathogens, provided an individual is healthy. [3] This means that urine can be readily utilized as a fertilizer or discharged with less risk to community. [4]

Human feces, on the other hand are high in pathogens, including up to 120 viruses and need to be treated well before it can be safely used in agriculture. The main two treatment methods are composting and drying. [5] When feces are used without composting, it is called night soil, and is very smelly.

Ash and/or sawdust are usually added to the feces chamber of a UDDT to speed the composting process. Of the two, ash decreases microbial activity faster. [6]

Whether the feces are handled on site or hauled to another location, the weight and volume of material is reduced by separating out urine. Additionally, treatment is simplified and faster. [7] Urine diversion can also be used for composting toilets to reduce odor and reduce excessive moisture.

Types of urine diversion devices

Urinals

Urine diversion toilet designs generally require men to sit or squat while urinating in order to avoid unhygienic splashing of urine. In cultures where males prefer to stand for urination, urinals are a good complementary solution. Urinals are commonly used in public toilets for male users. They collect urine separately from feces. So called "waterless urinals" use no water for flushing and therefore collect the urine undiluted. [1] There are many suppliers for waterless urinals. [8] :8

Urine-diversion flush toilets (UDFTs)

Urine diversion flush toilets have been manufactured in two main countries: Germany and Sweden. [9] In Germany, the company Roediger Vacuum sold the "NoMix" toilet [10] between 2003 - 2011. However, this toilet did not become a commercial success, and manufacturing, sales and technical support ceased in about 2010. [11] Likewise, the Swedish company Gustavsberg stopped selling their urine diversion flush model in about 2011.

In Sweden, urine diversion flush toilets are still supplied by two manufacturers, Dubbletten and Wostman, which continue to sell their urine diversion systems today primarily for installation in summer houses in rural and semi-rural areas. These two types of urine diversion flush toilets have been installed in both research projects and community scale installations in Australia. [12] [13]

The design difference between the various models is the shape and size of the two compartments and in the way the flush water is introduced for the two compartments. In addition, the Roederig NoMix toilet was the only toilet that was able to collect the urine pure - without any flush water - due to a valve on the urine compartment that was opened when the user sat down and closed when the user stood up and flushed the toilet. It was also this valve that caused a lot of maintenance issues due to struvite precipitation in this valve. [10] In the other urine diversion flush toilet models, the urine is diluted with a small amount of flush water, usually about one litre per flush.

Urine-diverting dry toilets (UDDTs)

Disadvantages

It is unclear whether urine diversion (source separation) and on-site urine treatment can be made cost effective; nor whether required behavioral changes would be regarded as socially acceptable. There are some successful trials performed in Sweden. [14]

Disadvantages and challenges with urine diversion systems include:

History

Historically, urine was collected (for example in chamber pots) and used for industrial processes, particularly fulling, an important step in textile manufacture.[ citation needed ]

See also

Related Research Articles

<span class="mw-page-title-main">Flush toilet</span> Toilet that uses water to convey human waste down a pipe

A flush toilet is a toilet that disposes of human waste by using the force of water to flush it through a drainpipe to another location for treatment, either nearby or at a communal facility, thus maintaining a separation between humans and their waste. Flush toilets can be designed for sitting or squatting, in the case of squat toilets. Most modern sewage treatment systems are also designed to process specially designed toilet paper. The opposite of a flush toilet is a dry toilet, which uses no water for flushing.

<span class="mw-page-title-main">Urinal</span> Sanitary fixture for urination

A urinal is a sanitary plumbing fixture for urination only. Urinals are often provided in public toilets for male users in Western countries. They are usually used in a standing position. Urinals can be with manual flushing, automatic flushing, or without flushing, as is the case for waterless urinals. They can be arranged as single sanitary fixtures or in a trough design without privacy walls. Urinals designed for females also exist but are rare. It is possible for females to use stand-up urinals using a female urination device.

<span class="mw-page-title-main">Composting toilet</span> Type of toilet that treats human excreta by a biological process called composting

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 by microorganisms under controlled aerobic conditions. Most composting toilets use no water for flushing and are therefore called "dry toilets".

Human waste refers to the waste products of the human digestive system, menses, and human metabolism including urine and feces. As part of a sanitation 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 being used, ability by the users to pay for services and other factors. Fecal sludge management is used to deal with fecal matter collected in on-site sanitation systems such as pit latrines and septic tanks.

<span class="mw-page-title-main">Pit latrine</span> Toilet that collects human waste in a hole in the ground

A pit latrine, also known as pit toilet, is a type of toilet that collects human waste 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 comfort. Pit latrines can be built to function without water or they can have a water seal. 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. This decreases the transfer of pathogens between feces and food by flies. These pathogens are major causes of infectious diarrhea and intestinal worm infections. Infectious diarrhea resulted in about 700,000 deaths in children under five years old in 2011 and 250 million lost school days. Pit latrines are a low-cost method of separating feces from people.

<span class="mw-page-title-main">Chemical toilet</span> A toilet that collects human excreta in a holding tank and uses chemicals to minimize odors

A chemical toilet collects human excreta 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 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 needs to be emptied frequently. It is not connected to a hole in the ground, nor to a septic tank, nor is it plumbed into a municipal system leading to a sewage treatment plant. When the tank is emptied, the contents are usually pumped into a sanitary sewer or directly to a treatment plant.

<span class="mw-page-title-main">Bucket toilet</span> Basic form of a dry toilet with a bucket

A bucket toilet is a basic form of a dry toilet whereby a bucket (pail) is used to collect excreta. Usually, feces and urine are collected together in the same bucket, leading to odor issues. The bucket may be situated inside a dwelling, or in a nearby small structure.

Blackwater in a sanitation context denotes wastewater from toilets which likely contains pathogens that may spread by the fecal–oral route. Blackwater can contain feces, urine, water and toilet paper from flush toilets. Blackwater is distinguished from greywater, which comes from sinks, baths, washing machines, and other household appliances apart from toilets. Greywater results from washing food, clothing, dishes, as well as from showering or bathing.

<span class="mw-page-title-main">Ecological sanitation</span> Approach to sanitation provision which aims to safely reuse excreta in agriculture

Ecological sanitation, commonly abbreviated as ecosan, is an approach to sanitation provision which aims to safely reuse excreta in agriculture. It is an approach, rather than a technology or a device which is characterized by a desire to "close the loop", mainly for the nutrients and organic matter between sanitation and agriculture in a safe manner. One of the aims is to minimise the use of non-renewable resources. When properly designed and operated, ecosan systems provide a hygienically safe system to convert human excreta into nutrients to be returned to the soil, and water to be returned to the land. Ecosan is also called resource-oriented sanitation.

<span class="mw-page-title-main">Urine</span> Liquid by-product of metabolism in the bodies of many animals, including humans

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 excreted from the body through the urethra.

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<span class="mw-page-title-main">Sustainable sanitation</span> Sanitation system designed to meet certain criteria and to work well over the long-term

Sustainable sanitation is a sanitation system designed to meet certain criteria and to work well over the long-term. Sustainable sanitation systems consider the entire "sanitation value chain", from the experience of the user, excreta and wastewater collection methods, transportation or conveyance of waste, treatment, and reuse or disposal. The Sustainable Sanitation Alliance (SuSanA) includes five features in its definition of "sustainable sanitation": Systems need to be economically and socially acceptable, technically and institutionally appropriate and protect the environment and natural resources.

<span class="mw-page-title-main">Toilet</span> Piece of hardware for the collection or disposal of human excreta

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 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.

<span class="mw-page-title-main">Arborloo</span> Composting toilet

An arborloo is a simple type of composting toilet in which feces are collected in a shallow pit and a fruit tree is later planted in the fertile soil of the full pit. Arborloos have: a pit like a pit latrine but less deep; a concrete, ferrocement or other strong floor; a superstructure to provide privacy; and possibly a ring beam to protect the pit from collapsing. The pit should remain well above the water table in the soil, so as to not contaminate groundwater.

<span class="mw-page-title-main">Dry toilet</span> Toilet that operates without flush water

A dry toilet 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 are not connected to a sewer system or septic tank. Instead, excreta falls through a drop hole.

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<span class="mw-page-title-main">Urine-diverting dry toilet</span> Dry toilet with separate collection of feces and urine without any flush water

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, 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 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.

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<span class="mw-page-title-main">Reuse of human excreta</span> Safe, beneficial use of human excreta mainly in agriculture (after treatment)

Reuse of human excreta is the safe, beneficial use of treated human excreta after applying suitable treatment steps and risk management approaches that are customized for the intended reuse application. Beneficial uses of the treated excreta may focus on using the plant-available nutrients that are contained in the treated excreta. They may also make use of the organic matter and energy contained in the excreta. To a lesser extent, reuse of the excreta's water content might also take place, although this is better known as water reclamation from municipal wastewater. The intended reuse applications for the nutrient content may include: soil conditioner or fertilizer in agriculture or horticultural activities. Other reuse applications, which focus more on the organic matter content of the excreta, include use as a fuel source or as an energy source in the form of biogas.

<span class="mw-page-title-main">Container-based sanitation</span> Sanitation system which uses removable containers

Container-based sanitation refers to a sanitation system where toilets collect human excreta in sealable, removable containers that are transported to treatment facilities. This type of sanitation involves a commercial service which provides certain types of portable toilets, and delivers empty containers when picking up full ones. The service transports and safely disposes of or reuses collected excreta. The cost of collection of excreta is usually borne by the users. With suitable development, support and functioning partnerships, CBS can be used to provide low-income urban populations with safe collection, transport and treatment of excrement at a lower cost than installing and maintaining sewers. In most cases, CBS is based on the use of urine-diverting dry toilets.

References

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