The general objective of the MEDRAR project is to develop and experimentally demonstrate an innovative and sustainable modular system of wastewater treatment for small populations adapted to the characteristics of the flow of water to be treated and the standards of effluent discharge or the reuse of treated water. It applies to urban waste water or gray and black waters both for small population areas or small urban / industrial agglomerations with separate networks, as well as for areas that do not have these systems.