Experience with compact mobile wastewater treatment unit in camps?

We are exploring the option of installing a compact mobile wastewater treatment unit in an IDP camp. Existing excreta disposal facilities are pit and pour-flush latrines; there are also laundry points and bucket-showers connected to the existing sewer network. No treatment is taking place at this time. The maximum camp population is around 28,000 but can fluctuate considerably. Temperatures in the cold season typically do not go below 0 C, however can reach into the 40s C during the hot season. Does anyone have experience with compact mobile systems in a similar situation - what are the major considerations, pitfalls, challenges? Thank you.