Dear Dr Umar,
Thank you for informing about this exciting project. Perhaps India's experience in rapidly increasing coverage of toilets and reducing open defecation could be relevant for this programme. While it was not a fool-proof programme, and questions about its sustainability, issue of safety of workers, appropriateness of on-site systems, among others have been asked and continue to be asked. In my opinion, it was very successful because of political sponsorship and incentive subsidies for households to construct toilets. Check out related discussions on the forum  Indian Government initiatives: Swachh Bharat Abhiyan (SBA or SBM) and others

You could check out the Wikipedia article on Swachh Bharat Mission  (FYI: SuSanA moderators contributed to its writing and editing). 

Feel free to reach out if you have questions about the Indian experience. I'd also encourage you to keep us updated about the project's progress so that we can contribute in whatever ways we can, and be a part of it.

Regards
paresh

PS: The image you attached is not visible. Could you please edit the post to include it. 

Gombe state government is one among the Seven state that are currently benefitting on sustainable urban and Rural Water Supply sanitation and hygiene (SURWASH) World Bank assisted program. the program aimed at achieving open defecation free state by the year 2027  through provision, construction, upgradement and rehabilitation of poor and vulnerable house hold latrine as well as institutional latrine of educational  and health institution. The Gombe State Environmental Sanitation and Protection Agency (GOSEPA) is saddle with the responsibility of providing, upgradement, construction and rehabilitation of poor and vulnerable house hold latrine as well as health and educational institution for Urban and Small Town. Currently the agency in 2023 conducted need assessment and baseline data of sanitation and hygiene in 32 communities that captured over 20,000 poor and vulnerable house hold latrine. The agency under Gombe State Government Improved over 2,000 poor and vulnerable house hold in 7 communities which include Kwami, Gadam, Bojude, Shamaki, Jekadafari, Pantami and Kumo. The agency used Sato pan, Sato Stools for the latrine improvement (Sanitation) and Sato tap for Hygiene.

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The agency also train over 100 toilets Business Owners, Public Convenience Association and Environmental Service Providers apart from community mobilization, sensitization and advocacy on behavioral  change communication and other methodology to facilitate ending open defecation in the state.