Pollution and eutrophication are big threats to all our water bodies. In almost all developing countries, domestic untreated sewage flows into rivers, lakes, lagoons and generally into the landscape. This issue becomes of large relevance in isolated rural areas where the discharge of wastewater from communities generates not only an enormous environmental problem - stressing the ecological balance of aquatic ecosystems - but also a humanitarian challenge, as local residents suffer the consequences of inadequate sanitary and hygiene conditions. Although being implemented in Colombia, Paraguay, Mexico and Nicaragua, and in five different scenarios, the problems to be tackled with this project share the same ground, the lack of efficient wastewater treatment technologies in households and public facilities is leading to a severe deterioration of the living conditions of the inhabitants, who specially in poor rural communities dependent on the use of surface water. This unsatisfactory waste water situation has also massive negative effects on ecosystem services (for example, water and biodiversity) on site. In rural areas these problems cannot be solved as in industrialized countries by central, technical wastewater treatment plants because of high construction and operating costs.
Against this background, the "natural" way to treat wastewater in constructed wetlands represents a plausible and viable alternative. Following an innovative biomimicry approach, the so called Green Filter is a cost effective solution to sewage treatment based on natural processes of contaminant degradation in wetlands. This technology and its advantages have successfully been proven in four different communities in Colombia. Following the same strategy this technology will be transfer to Nicaragua, Mexico and Paraguay as well as to a new filter in Colombia.