Testing of new pit latrine designs?
This question was posted by Rochelle Holm in the SuSanA forum http://forum.susana.org/forum/categor... but nobody answered it.
"In Malawi, we have been working through participatory design to develop new pit latrine designs, for both rural and peri-urban areas.
See Going Beyond ODF: Combining Sanitation Marketing with Participatory Approaches to Sustain ODF Communities in Malawi ( http://www.unicef.org/esaro/WASH-Fiel... ).
For others that are also working on new latrine designs, what are you doing in terms of testing the safety and durability of the new sanitation technology designs for rural and peri-urban communities before scale-up?"
Before testing you have to decide what standards you are looking for. A temporary solution may not last long but may be sustainable as people can afford to replace it. Consider the sanitation ladder and you will see that each step has different cost/ benefits. The key factors are separation of excreta from people and no smell, no flies.
Structurally, standards are more difficult as the geotechnical (pit) and structural (slab) designs will depend on technical factors such as soil type, soil moisture, rainfall, material quality, pit dimensions. One way to overcome this is to look at the quality of the inputs (e.g. capacity of staff) rather than judge the design. Exacting standards can make latrines unaffordable (e.g. problems insisting on a VIP) and therefore set back sanitation provision but inadequate designs are also not good. One way to move forward incrementally is to identify common failure mechanisms and address those. Erosion due to poor surface water management is a common error.
Hi Brian, Thanks for your very helpful and thoughtful response.
For the structural standards: For example, now we are doing load testing on the new latrine design with a 210 L drum of water sitting on top of a test latrine for several weeks to mimic user weight. We also did testing of local bricks with a compressive strength test showed only 33% passed, not a very good rate. Mostly looking for more ideas similar to these that we should try.
For the human dimensions: We have been running ongoing trainings for the masons and currently are doing a tracer study to see what is working and how we can expand the training program. I agree this is a very important variable but want to ensure the design is safe as a priority.
Thank you again, your response was very helpful and gave our team some good ideas.
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