Can you share us any experience in establishing sustainable management system for a public toilet in slum community?

I am Project Coordinator supporting sanitation project implemented by Hope for Children and funded by Events for Namuwongo. Under this sanitation project,Hope for Children (UK-based charity) has constructed 3 public toilets within community of Namuwongo, one of theslums in Kampala. One of the toilet was operational since 21st January 2014, but two are not yet operational. The first toilet was opened to public free of charge for two week and then a user fee of 100/= per visit was introduced for adults, but children continue accessing the services for free. Most existing private toilets charge 200/= visit, so through opinion survey, we set user fee at 100/=. When toilet access was free to all, the average daily visit was 1326 people and after introduction of payment, the average daily dropped to 416 during February and 350 during March. The fundamental question is around the sustainability. We have so far collected about 916,000/= since payment was introduced, but amount of money used since the toilet was operational exceed 5,800,000/=. Some of the existing private toilets are owned by local leaders and one of the fear is that during project exit handing these toilets to them will automatically lead to them owning them as their private properties. These community are considered as illegal occupantsinto government land (railway land reserve and wetland), so they legally don't own any land. Hope for Children's intervention was necessitated by extremely poor sanitation conditions and public health risk, but land ownership had been one of the critical challenge during the implementation. Therefore, does any one has a sustainable business model of running such a public toilet in an informal settlement (slum) area? Please share your ideas with me at draleketm@gmail.com