evidence: Ringiti Island is basically the same size (500 meters diameter - see map) and has about 5000 inhabitants. All fisherman with families! The basic demand was safe drinking water, so they thought that by producing biogas from sanitation and kitchenwaste they can run a generator to pump the lake water into this gravety sand filter treatment. As a side effect they would also have enough water for flushing the toilets....see pictures attached [...] I was involved in a sanitation concept development for an island in Lake Victoria called Ringiti island on the Kenyan side. They leading NGO was called Globology Ltd, however the project did not take off as proposed. I will try to get in touch with him. Maybe he could give you some interesting feedback.