The Conference follows the tradition of biennial meetings of theoreticians, engineers and practitioners working on treatment wetlands. A special emphasis will be done, linking wetlands systems – pollution control – biodiversity. Spain is the UE-28 country richer in biodiversity with many Natura 2000, several natural wetlands in high risk with more and more water scarcity because the global change. The conference is an opportunity to bring together experiences in treatment wetlands for water reuse in small communities. Spain is not an example of broad use of treatment wetlands so the conference is an opportunity to spread the benefits sharing the knowledge leaned in other countries and promoting the use.