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<br>[[Image:Icon_single_ventilated_improved_pit.png |right|95px80px]]
'''The Single VIP is a Ventilated, Improved Pit. It is an improvement over the Single Pit because continuous airflow through the ventilation pipe vents odours and acts as a trap for flies as they escape towards the light.'''
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===Adequacy===
Treatment processes in the Single VIP (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. This technology is a significant improvement over Single Pits or open defecation. Single VIPs are appropriate for rural and peri-urban areas; single pits in urban or dense areas are often difficult to empty and/or have insufficient space for infiltration. Depending on the pit depth, depth to the water table, number of users and soil conditions, some pits can be used for 20 years without emptying. VIPs are especially appropriate when water is scarce and where there is a low groundwater table. They should be located in an area with a good breeze. They are not suited for rocky or compacted soils (that are difficult to dig) or for areas that flood frequently.
===Health Aspects/Acceptance===
A Single VIP can be a very clean, comfortable, and well accepted sanitation option. However some health concerns exist:
* Health risks from flies are not completely removed by ventilation.
===Upgrading===
A Single VIP toilet can be upgraded to a [[Double Ventilated Improved Pit|Double VIP]], a [[Urine Diverting Dry Toilet|Urine Diverting Dry Toilet (UDDT)]] if there is a use for urine, or a water-based [[Pour Flush Toilet|Pour Flush Toilet]] if water is available. A Double VIP has the addition of an extra pit so that while one pit is in use, the contents of the full pit are draining, maturing and undergoing degradation. Pathogens are destroyed much more thoroughly in a Double VIP and therefore, the contents are less hazardous to remove from the pit, although because the contents are so solid, the contents cannot be pumped, but rather, must be manually emptied.
===Maintenance===
To keep the Single VIP free of flies and odours, regular cleaning and maintenance is required. Dead flies, spider webs, dust and other debris should be removed from the ventilation screen to ensure a good flow of air.
===Origins===
The VIP latrine was developed in the 1970s at the Blair Research Laboratory in Zimbabwe.
===Field experiences===
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|[[Image:rsr 476.jpg|thumb|none|200px|<font size="2"><center>Project 476</center></font>|link=http://www.akvo.org/rsr/project/476/]]
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===References ===
* Mara, DD. (1996). Low-Cost Urban Sanitation. Wiley, Chichester, UK. (Provides detailed design information.)
* The World Bank (1986). Information and Training for Low-Cost Water Supply and Sanitation (UNDP Project INT/82/002). The World Bank, Washington.
===Acknowledgements===
{{:Acknowledgements Sanitation}}