Firstly, we must understand that latrines are not like WCs. They require emptying. When planning to build a latrine, one must also plan on the emptying of the latrine during it's service life. Clearly, the latrines built in the target schools near Gulu had little (or inaccurate) financial outlook. It is like using a garbage can without first knowing who's emptying it.
The second point is then, why does emptying latrines cost so much money? The reason is because specialized equipment is needed to carry out the work. While use of smaller equipment like the Gulper provides cheap alternatives to latrine emptying, the hygienic risks are also higher, meaning more training is needed if such equipment is to be used effectively. Training takes time and money, something that is rather impractical if to be implemented in a large scale (because it involves little incentive structures). Even though larger machines like septic trucks and Vactugs do a cleaner and quicker job than Gulpers, they are expensive. Getting large machines to remote countryside areas is also also difficult and costly.
This above leads me to my last point, which raises the question, why do latrines need big machinery to operate? Can frugality be part of the design of the latrine so that it can be independent of big machinery? I believe so. The equipment needed to empty latrines nowadays are all there to deal with one main problem, gravity. Emptying latrines means transferring sludge from the latrine to a transport to be taken away. Unfortunately, that process is always against gravity. Many types of machinery are designed to combat the gravitation pull of the sludge, often making the process of latrine emptying messy and costly.
So to conclude my thoughts, I would like to ask the next latrine designers to think of how to make gravity work in your favor rather than against you. If sludge can simply flow from the latrine into the transport container, it would solve the largest financial obstacle our group is facing now.