Black Water Tank

I have been a member of this forum for a while I have basically been a sideliner trying to learn more from the experience of Trailmanor owners. We like the product very much and feel one may be in our future. We have gotten a lot of valuable information from this forum and most of our questions have been answered. However, I have one question, that through my research of past posts, I have been unable to answer. Why does Trailmanor use a reciuculating toilet instead of the tradition RV toilet with a separate blackwater tank installed beneath the trailer?