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Traditional pit latrine:
The simple pit latrine is the cheapest and most basic form of improved sanitation available. It consists of a square rectangular or circular pit dug into the ground, covered by a hygienic cover slap or floor with a hole through which excreta fall into the pit. Depending on user preference a seat or squat hole with footrests can be installed, and a lit supplied to cover the hole. The latrine is covered with a shelter and fitted with a door, and is situated well away from water sources and some distance from the house. The simple pit latrine is most appropriate when water is not used for anal cleansing. (Source: MajiData).Traditional pit latrines usually consist of a single pit covered by a slab with a drop hole and a superstructure. The slab may be made of wood (sometimes covered with mud) or reinforced concrete. The superstructure provides shelter and privacy for the user. Basic improvements include a hygienic self-draining floor made of smooth, durable material and with raised foot rests; a tight-fitting lid that covers the drop hole, to reduce smells and keep insects out of the pit; a floor raised above ground level to prevent flooding; an adequately lined pit, to prevent the pit collapsing (e.g. when the soil is unstable); and an adequate foundation, to prevent damage of the slab and superstructure (WHO 2003). If a latrine is a dry pit it will not penetrate the water table. If the pit is wet, then the water table is at risk (Source: World Plumbing Council Working Group 2008). It is recognised that although not ideal, a pit latrine allows for safer and more hygienic disposal of human waste than open defecation (World Plumbing Council Working Group 2008). A pit latrine is not suitable where there are high population densities (Source: World Plumbing Council Working Group 2008; www.waterwiki.net).
Improved Pit Latrine (IP) (air-vent, proper superstructure): A top-structure over a pit. The pit may be lined (recommended where emptying is required), or unlined where soil conditions allow. The improved pit latrine is seen as the basic sanitation facility people in Kenya should have access to. (Source: MajiData).
Pit latrine with slab: is a dry pit latrine that uses a hole in the ground to collect the excreta and a squatting slab or platform that is firmly supported on all sides, easy to clean and raised above the surrounding ground level to prevent surface water from entering the pit. The platform has a squatting hole, or is fitted with a seat. (Source: JMP; http://www.wssinfo.org/definitions-methods/watsan-categories/).
Ventilated Improved Pit latrine (VIP) (vent pipe, fly screen):
A top-structure over a pit. The pit is vented by a pipe over which a fly-screen is fixed. The pit may be lined (recommended where emptying is required), or unlined where soil conditions allow. It also can be constructed as a double pit system.
A dry pit latrine ventilated by a pipe that extends above the latrine roof. The open end of the vent pipe is covered with gauze mesh or fly-proof netting and the inside of the superstructure is kept dark. (Source: JMP; http://www.wssinfo.org/definitions-methods/watsan-categories/).
Composting toilet: A dry toilet into which carbon-rich material (vegetable wastes, straw, grass, sawdust, ash) are added to the excreta and special conditions maintained to produce inoffensive compost. A composting latrine may or may not have a urine separation device. (Source: JMP; http://www.wssinfo.org/definitions-methods/watsan-categories/).
Urine Diversion (UD) Toilet: A single top-structure over a sealed container, which could be one of two chambers side by side (as for the VIDP), with access for the removal of decomposed waste. A vent pipe may be installed to encourage drying of the waste.
Urine diversion: Is the process of separating urine from faeces composting toilet system very easily manageable. (Source: Wikipedia). at the time of using toilet (at the source). Mixing of urine with faeces is the main cause of bad odours and flies. Separated faeces dry quickly, especially if regular soil, ash, leaves or other bulking agents such as, saw-dust is used. Drying out process further reduces odour, flies and also avoids contamination. Urine is generally pathogen-free and by mixing with water it can be readily used as a fertilizer for both edible and non-edible plants. Separated faeces along with other covering material such as soil, leaves, etc. can be placed in a compost pile to have it decomposed and completely pathogen free. Once it is composted, it can be used as household fertilizer as well. Another major advantage of urine diversion is that it dramatically reduces size of materials in toilet and makes the whole
Flying toilets are particularly associated with Slums surrounding Nairobi, Kenya, especially Kibera. According to a report from the United Nations Development Programme launched in Cape Town on November 9, 2006, "two in three people [in Kibera] identify the flying toilet as the primary mode of excreta disposal available to them." (Source: Wikipedia; UN-Habitat).
Toilet with raised platform and open discharge: A hanging toilet or hanging latrine is a toilet built over the sea, a river, or other body of water, into which excreta drops directly. (Source: JMP; http://www.wssinfo.org/definitions-methods/watsan-categories/).
Open defecation: No facilities or bush or field includes defecation in the bush or field or ditch; excreta deposited on the ground and covered with a layer of earth (cat method); excreta wrapped and thrown into garbage; and defecation into surface water (drainage channel, beach, river, stream or sea). (Source: JMP; http://www.wssinfo.org/definitions-methods/watsan-categories/).
Biogas latrine (bio-digester):
In a biogas plant the waste undergoes anaerobic fermentation which kills practically all bacteria and worms and allows the slurry to be used as a fertilizer for vegetable cultivation. After a retention time of 20-30 days the slurry is odourless and therefore does not attract flies. The methane gas produced in the fermentation process can be used for cooking or lighting. These advantages make the biogas latrine a favourable option for waste treatment in educational institutions and hospitals.
Digestion is accomplished in two general stages. First, acidogenic bacteria turn biomass into volatile fatty acids and acetic acid. Then methanogenic bacteria metabolize these compounds into a combination of methane-rich gas and an odourless phosphorus- and nitrogen-laden slurry, which makes excellent fertilizer. Depending on temperature and moisture content, it takes about 6-25 days to fully process a batch, according to a fact sheet from WASTE, a development NGO based in the Netherlands. Simpler digesters take longer. The end product is about 60-70% methane and 20-30% C[C.sub.2], with small amounts of hydrogen sulphide and other impurities. The gas can be connected to a household stove for cooking, to a light fixture with a gauze mantle for lighting, or to other appliances with simple natural gas plumbing; it burns like liquefied petroleum gas.
It takes 1-2 cows, 5-8 pigs, or 4 adult humans to supply adequate daily feedstock for a single-household bio-digester, according to a UNDP--Global Environment Facility fact sheet. The daily input of dung and urine from a single cow produces 1-2 kilowatt-hours of electricity or 8-9 kilowatt-hours of heat. Over a year, this is just about enough to run a refrigerator. In most African applications, a household biogas installation provides sufficient energy for cooking and some lighting.