Reed Odourless Earth Closet
Reed odourless earth closet is a variation on the ventilated improved pit (VIP) latrine. With ROEC, the pit is fully off-set from the superstructure and is connecting to the squatting plate by a curve chute. The ROEC is fitted with a vent pipe to control odour and insect nuisance. It is claimed that the chute, in conjunction with the ventilation stack, encourages vigorous air circulation down the latrine, thereby removing odors and discouraging flies. This latrine is common in southern Africa.
Design Consideration for ROEC
Design Life:The design life should be as long as possible; at least 10 years is desirables. The longer the design life , the longer the interval between relocating or emptying the latrine.
Dimensions:Usually the pit cross-sectional area should not be more than 2 m2 in order to avoid cover spans with large spans. In practice,ROEC serving one household commonly have a diameter of 1-1.5 m or in case of square or rectangular pits , a width of 1-1.5 m.
Vent Pipe:Vent pipe of a wide variety of materials are used, for example polyvinyl chloride (PVC), unplasticized PVC, bricks, etc. Whatever material is used, its durability (including corrosion resistance), availability, cost and ease of construction are important factors. The vent pipe should be sufficiently long so that the roof does not interfere with the action of wind across the top of the vent pipe. For flat roofs, top of the vent pipe should be at least 500mm higher than the roof , and in case of sloping roof the vent pipe should be 500mm above the highest point of the roof.
The internal diameter of the vent pipe depends on the required venting velocity necessary to achieve the recommended ventilation rate 20 m3/hr. This in turn depends on factors like internal surface roughness of the pipe, its length(which determines the friction losses), the head loss through the flyscreen and wind direction. Recommendations for minimum internal size of vent pipes are as follows:
| Material used | Dimension |
|---|---|
| PVC | 150 mm diameter |
| Brick | 230 mm square |
| Others | 230 mm diameter |
Flyscreen Specification:The purpose of the flyscreen is to prevent passage of flies and mosquitoes; therefore, the mesh must not be larger than 1.2 mm × 1.5 mm. The flyscreen must be made of corrosion-resistant material that is able to withstand intense rainfall, high temperature and strong sunlight. It is preferable to use stainless steel screens.
Advantages:As the pit is offset from the squatting hole excreta will not seen, thus convenient to the users.
References
- Ahmed,M.F. & Rahman,M.M. (2003). Water Supply & Sanitation: Rural and Low Income Urban Communities (2nd Edition ed.). ITN-Bangladesh. ISBN 984-31-0936-8.
{{cite book}}:|edition=has extra text (help)CS1 maint: multiple names: authors list (link) - Workshop on community management of waste water (treatment and disposal)