Friday, April 1, 2011

Why Double Pit Latrines? Continual Improvement

Sneak preview of an article from our next newsletter:

Our philosophy has always been one of continual improvement. If we can do it better, then that's what we try to do. Since I started at El Porvenir, there has been a problem with our sanitation program, but we didn’t have a clear solution until now. The official latrine choice for the government and most groups working in Nicaragua has been the single pit VIP (ventilated improved pit) latrine.

Single pit latrines work well. They eliminate open defecation, contamination of water sources, smells and fly proliferation; they improve the community’s health. However, the problem is that they have a finite capacity. The usual depth of our latrines and the government latrines was about 3 meters or 10 feet deep. These usually filled up in 5-7 years with a typical family. After that, if the family didn’t take the initiative to build another, then they often returned to open defecation. Or, another organization came along and built another latrine, contributing to what we call “latrine cemeteries”. Resources were being wasted and trash created.  

Latrine cemetery: This photo shows 3 different sets of
new and abandoned latrines at a school in Terrabona.

So, we did some research and discovered another option from Africa, the double pit VIP latrine. We have been piloting double pit latrines in a few communities since 2007, building 200 to date. A double pit latrine is the same as the single, but has two pits. The beneficiary can use one pit until it fills, then can move the superstructure to the second pit. Once the second pit fills, then the first pit can be emptied as the bacteria will be dead by that time (likely 2-3 years for the pit to fill, although at least a year is needed for it to be safe). Then the superstructure can be moved back and forth between the pits, with luck endlessly.

Note the second pit on the left. Latrine from El Sauce.

So far, the results from the pilots are promising: 2 families have switched to their second pit. Seeing that the families are accepting the technology so far, we decided to eliminate single pit VIP latrines from our project portfolio in 2011. We’ll keep you up to date on how it is working with the double pits and other technologies but we are excited about this new, more sustainable initiative.   

p.s. Here is the technical design of this latrine, if you are interested, although it is a little faint (if you are having trouble seeing it, email us at and we can email this to you): 

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