<!{|style="float: left;"|{{Language-- table at top of page with logo, picture, Application level, Management level, and input-output tables -->box|english_link=Single_Pit|french_link=Latrine_traditionnelle|spanish_link=Pozo_Simple|hindi_link=coming soon|malayalam_link=coming soon|tamil_link=coming soon | korean_link=coming soon | chinese_link=Coming soon | indonesian_link=Coming soon | japanese_link=Coming soon}}|}{|width="100%"|style="width:50%;"|{{santablesantable_new|
sys1=[[Single Pit System|1]]|
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Input1=Excreta|Input2=Faeces Blackwater |Input3=Anal cleansing waterFaeces| Input4= Anal Cleansing Water |Input5=Dry Cleansing Materials|Output1=ExcretaSludge | Output2=Faecal sludge | Output3= | Output4= | Output5=|english_link=Single_Pit|french_link=Latrine_traditionnelle|spanish_link=Pozo_Simple
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'''The Single Pit is one of the most widely used sanitation technologies. Excreta, along with anal cleansing materials (water or solids) are deposited into a pit. Lining the pit prevents it from collapsing and provides support to the superstructure.'''
As the single pit fills, two processes limit the rate of accumulation: leaching and degradation. Urine and water percolate into the soil through the bottom of the pit and wall, while microbial action degrades part of the organic fraction.
As the Single Pit fills'''Design Considerations''': On average, two processes limit the solids accumulate at a rate of accumulation: leaching 40 to 60 L per person/year and degradationup to 90 L per person/year if dry cleansing materials such as leaves or paper are used. The volume of the pit should be designed to contain at least 1,000 L. Urine Typically, the pit is at least 3 m deep and anal cleansing water percolate into 1 m in diameter. If the soil through pit diameter exceeds 1.5 m, there is an increased risk of collapse. Depending on how deep they are dug, some pits may last 20 or more years without emptying. To prevent groundwater contamination, the bottom of the pit and wall while microbial action degrades part should be at least 2 m above groundwater level (rule of thumb). If the organic fractionpit is to be reused, it should be lined.
On average, solids accumulate at a rate of 40 to 60L per person/year and up to 90L per person/year if dry cleansing materials such as leaves, newspapers, and toilet paper are used. The volume of the pit should be designed to contain at least 1,000L. Ideally the pit should be designed to be at least 3m deep and 1 m in diameter. If the pit diameter exceeds 1.5m there is an increased risk of collapse. Depending on how deep they are dug, some pits may last up to 20 years without emptying. If the pit is to be reused it should be lined. Pit lining materials can include brick, rot-resistant timber, concrete, stones, or mortar plastered onto the soil. If the soil is stable (i.e. , no presence of sand or gravel deposits or loose organic materials), the whole pit need not be lined. The bottom of the pit should remain unlined to allow for the infiltration of liquids out of the pit. As liquid leaches from the pit and migrates through the unsaturated soil matrix, pathogenic germs are sorbed to the soil surface. In this way, pathogens can be removed prior to contact with groundwater. The degree of removal varies with soil type, distance travelled, moisture and other environmental factors and, thus, it is difficult to estimate the distance necessary between a pit and a water source. A minimum horizontal distance of 30m is normally recommended to limit exposure to microbial contamination.
As the effluent leaches from the Single Pit and migrates through the unsaturated soil matrix, faecal organisms are removed. The degree of faecal organism removal varies with soil type, distance travelled, moisture and other environmental factors and thus, When it is difficult not possible to estimate the necessary distance between dig a deep pit and a water source. A distance of 30m between or the pit and a water source groundwater level is recommended to limit exposure to chemical and biological contamination. When it is impossible or difficult to dig too high, a deep raised pit, the depth of can be a viable alternative: the shallow pit can be extending extended by building the pit upwards with the use of concrete rings or blocks. This adaptation A raised pit can also be constructed in an area where flooding is sometimes referred frequent in order to as a cesspitkeep water from flowing into the pit during heavy rain. It Another variation is a raised shaft on top of a the unlined shallow pit with an open bottom that allows may be appropriate for areas where digging is difficult. When the collection of faecal sludge and the leaching of effluent. This design howevershallow pit is full, is prone to improper emptying since it may can be easier to break or remove the concrete rings covered with leaves and allow the faecal sludge to flow out rather than have it emptied soil, and disposed of properlya small tree can be planted (see Arborloo, D.1).
A [[Single Ventilated Improved Pit|Ventilated Improved Pit]] (VIP, S.3) is slightly more expensive than a single pit, but greatly reduces the nuisance of flies and odours, while increasing comfort. If a urine-diverting User Interface is used, only faeces are collected in the pit and leaching can be minimized.
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Another variation is the unlined shallow pit that may be appropriate for areas where digging is difficult. When the shallow pit is full, it can be covered with leaves and soil and a small tree can be planted. This concept is called the Arborloo and is a successful way of avoiding costly emptying, while containing excreta, and reforesting an area. The Arborloo is discussed in more detail on the [[Fill and Cover - Arborloo]] section.
<br>{{procontable | pro=- Can be built and repaired with locally available materials.<br> - Does not require a constant source of water.<br> - Can be used immediately after construction. <br> - Low (but variable) capital costs depending on materialsand pit depth.<br> - Small land area required. <br> | con=- Flies and odours are normally noticeable. <br> - Sludge requires secondary treatment Low reduction in BOD and/or appropriate dischargepathogens with possible contamination of groundwater. <br> - Costs to empty may be significant compared to capital costs. <br> - Low reduction in BOD Sludge requires secondary treatment and pathogens/or appropriate discharge.
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==Adequacy=Appropriateness= == Treatment processes in a single pit (aerobic, anaerobic, dehydration, composting or otherwise) are limited and, therefore, pathogen reduction and organic degradation is not significant. However, since the excreta are contained, pathogen transmission to the user is limited.
Treatment processes in the Single Pit (aerobic, anaerobic, dehydration, composting or otherwise) are limited and therefore, pathogen reduction and organic degradation is not significant. However, since the excreta are contained, pathogen transmission to the user is limited. Single Pits pits are appropriate for rural and peri-urban areas; Single Pits in urban or dense densely populated areas they are often difficult to empty and/or have sufficient insufficient space for infiltration. Single Pits pits are especially appropriate when water is scarce and where there is a low groundwater table. They are not suited for rocky or compacted soils (that are difficult to dig) , or for areas that flood frequently.
===Health Aspects/Acceptance===A simple Single Pit is an improvement to open defecation; however, it still poses health risks:
A simple Single Pit is an improvement to open defecation; however, it still poses health risks:
* Leachate can contaminate groundwater;
* Stagnant water in pits may promote insect breeding;
*Pits are susceptible to failure/overflowing during floods.
Single Pits pits should be constructed at an appropriate distance from homes to minimize fly and odour nuisances and to ensure convenience and safe travelsafety.
===Upgrading== = A [[Single Ventilated Improved Pit|Ventilated Improved Pit (VIP)]] is slightly more expensive but greatly reduces the nuisance of flies and odours, while increasing comfort and usability. For more information on the VIP please refer to the [[Single Ventilated Improved Pit|Single Pit VIP]] page. When two pits are dug side-by-side, one can be used while the contents of the other pit are allowed to mature for safer emptying. For more information on dual pit technologies refer to [[Double Ventilated Improved Pit|Double Pit VIP]] and [[Twin Pits for Pour Flush]] pages.
A [[Single Ventilated Improved Pit|Ventilated Improved Pit (VIP)]] ===Operation & Maintenance=== There is slightly more expensive but greatly reduces no daily maintenance associated with a single pit apart from keeping the nuisance of flies and odoursfacility clean. However, while increasing comfort when the pit is full it can bea) pumped out and usability. For more information on reused or b) the VIP please refer to the [[Single Ventilated Improved Pit|Single Pit VIP]] page. When two pits are dug side-by-side, one superstructure and squatting plate can be used while the contents of moved to a new pit and the other previous pit are allowed to mature for safer emptying. For more information on dual pit technologies refer to [[Double Ventilated Improved Pit|Double Pit VIP]] covered and [[Twin Pits for Pour Flush]] pagesdecommissioned, which is only advisable if plenty of land area is available.
==Maintenance=Field experiences= =={|style="border: 2px solid #e0e0e0; width: 40%; text-align: justify; background-color: #e9f5fd;" cellpadding="2"<!--rsr logo here-->|- style="vertical-align: top"|[[Image:akvorsr logo_lite.png|center|60px|link=http://akvo.org/products/rsr/]]<!--project blocks here-->|- style="vertical-align: bottom"|[[Image: rsr 476.jpg|thumb|center|140px|<font size="2"><center>[http://rsr.akvo.org/project/476/ RSR Project 476]<br>Ensure access to safe water and sanitation</center></font>|link=http://rsr.akvo.org/project/476/ ]] |[[Image: rsr 819.jpg|thumb|center|140px|<font size="2"><center>[http://rsr.akvo.org/project/819/ RSR Project 819]<br>Water, Food & Sanitation for School + Community</center></font>|link=http://rsr.akvo.org/project/819/ ]] |}
There is no daily maintenance associated with a simple Single Pit===References ===* ARGOSS (2001). [http://nora.nerc. However, when the pit is full it can be a) pumped out and reused or b) ac.uk/id/eprint/20757/1/ARGOSS%20Manual.PDF Guidelines for Assessing the superstructure and squatting plate can be moved Risk to a new pit and the previous pit covered and decommissionedGroundwater from on-Site Sanitation]. British Geological Survey Commissioned Report, CR/01/142, Keyworth, UK.
==Acknowledgements=={{:Acknowledgements Sanitation}}* Brandberg, B. (1997). Latrine Building. A Handbook for Implementation of the Sanplat System. Intermediate Technology Publications, London, UK. (Book; a good summary of common construction problems and how to avoid mistakes)
==References * Franceys, R., Pickford, J. and external links==Reed, R. (1992). [https://www.susana.org/_resources/documents/default/2-1651-who-a-guide-to-the-development-of-on-site-sanitation.pdf A Guide to the Development of on-Site Sanitation]. WHO, Geneva, CH. (For information on accumulation rates, infiltration rates, general construction and example design calculations)
* BrandbergGraham, BJ. P. and Polizzotto, M. L. (19972013). Latrine Building[https://pubmed. ncbi.nlm.nih.gov/23518813/ Pit Latrines and Their Impacts on Groundwater Quality: A Handbook for Implementation of the Sanplat SystemSystematic Review]. Intermediate Technology PublicationsEnvironmental Health Perspectives, London. (A good summary National Institute of common construction problems and how to avoid mistakesEnvironmental Health Sciences, Research Triangle Park, US.)
* Franceys, R., Pickford, J. and Reed, R. (19921995). Low Cost Sanitation. A guide to the development Survey of on-site sanitationPractical Experience. WHOIntermediate Technology Publications, London, GenevaUK. (For information Book; Information on accumulation rates, infiltration rates, general construction how to calculate pit size and example design calculations.technology life)
* Lewis, JWRobens Institute (1996). [http://helid.digicollection., et alorg/en/d/Js13461e/3. (1982)4. The Risk of Groundwater Pollution by html Fact Sheets on-site Environmental Sanitation in Developing Countries. International Reference Centre for Waste Disposal, Dübendorf, SwitzerlandFact Sheet 3.4: Simple Pit Latrines]. (Detailed study regarding the transport and die-off University of microorganisms Surrey, UK and implications for locating technologiesWHO, Geneva, CH.)
* Morgan, P[http://www. (2007)who. Toilets That Make Compostint/water_sanitation_health/publications/guidelines-on-sanitation-and-health/en/ WHO: LowGuidelines on sanitation and health -cost, sanitary toilets that produce valuable compost for crops in an African context. Stockholm Environment Institute, Sweden. (Describes how to build a support ring/foundation.)2018]
* Pickford, J. (1995). Low Cost ===Acknowledgements==={{:Acknowledgements Sanitation. A Survey of Practical Experience. Intermediate Technology Publications, London. (Information on how to calculate pit size and technology life.)}}