I suspect there are a few units being used for promotional purposes. Set it up, let it run for a few hours, provide water to the locals, take pictures with the local politicians.....then ship it to the next location for another promotion. But, that's just me - a skeptic.
I do not believe that if one of those units were set up in a little village in Cameroon (or any third world nation) that it would last more than a day or two. Tires gone, anything metal gone, tanks repurposed, and so on......Who's going to guard it, maintain it, etc.?