Faecal sludge pump lifespan in urban settings
I think this question should be opened to people beyond WaterAid to help! I don't think there is an established lifespan for the current alternative pumps like the Gulper and so on, mostly because they are so recent. Such simple mechanisms can go on for ages but then you replace the parts that fail as you go along, until all parts have been replaced at least once... for example with the Gulper you would expect frequent repairs of the bottom valve and, depending on the quality of local welding, of connections between welded parts.
For budget planning purposes, with large items like trucks you factor in depreciation costs, but for small pumps like the Gulper it is easier and more realistic to put in annual maintenance costs (frequently 20% of the purchase value per year).
For more complex systems, well the Vacutug has been going on for more than 10 years in some places so 10 years could be put in, although with high maintenance costs (as spare parts often come from far). The MAPET hasn't worked for long enough to my knowledge to assess the lifespan (happy to be contradicted on that!). And large vacuum tankers, if well maintained, can last well over 30 years, and Africa is full of tankers well over that age!
Well like Remi said above, the gulper is a simple mechanism that is doing great in urban settings. It can do what trucks can do save for the manual usage establishment. I am a proud gulprenuer that has only been in business since late September but the only time of service has been on the valve which was done free. Haven't had issues worth disposing it. I hope to see how much longer it will work.
P.S. I am using the Gulper 1.
Are you looking for a practical answer or a theoretical answer. From an asset management point of view, the economic life span of mechanical components should be 15 years - with probably 10% maintenance cost per year.
In a developing country context, I would say that if your equipment is not local, then this should still apply (albeit with a higher maintenance cost - potentially), and if it is locally made, then perhaps 5-10 years, depending on the quality of the local workmanship and materials. But on the other hand, people can be very good at making things last a lot longer than the theoretic economic life.
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