Green filters as a solution for waste water treatement in off-grid communities in rural areas of Latin America and beyond

Green filters clean sewage water and protect open waters, drinking water and irrigation water and contribute to rural poverty evaliation.

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I confirm that I am fully aware of the eligibility criteria, and based on its description, I am eligible to apply to the CSV Prize 2017.

  • Yes, I'm eligible

Preferred language

  • English

Organization name

Fundación Humedales

Year founded


Initiative stage

  • Scaling (the solution has passed the previous stages and is growing its impact on a regional or global scale)

Annual budget in 2017 (USD)

  • $50k - $100k

Number of beneficiaries impacted so far

  • 5,000 - 10,000

Organization type

  • Nonprofit, NGO, or citizen sector

Secondary Focus Area

  • Rural development

Headquarters location: Country

  • Colombia

Headquarters location: City


Location(s) of impact

Colombia: San Miguel, Quitiva, Susa, Fuquene Nicaragua: to be defined Philippines: Seven Lake Mexico: Corazón de la Tierra Paraguay: Mbarakayu NP


Facebook URL

Twitter URL

Problem: What problem is this initiative trying to address?

Pollution and eutrophication are big threats to all our water bodies. In developing countries, domestic untreated sewage flows into rivers, lakes, lagoons and landscape. This issue becomes large relevance in isolated rural areas where the discharge of wastewater 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.

Solution Summary: What is the proposed solution? What do you see as its most promising aspects for creating shared value?

Green filter is a cost effective solution to sewage treatment based on natural processes of contaminant degradation in wetlands. Green filter consists of a grid of open channels planted with floating aquatic macrophytes receiving wastewater after a basic primary treatment. The roots of the macrophytes function as a substrate for bacteria and form the core part of the filtering process. Like in natural wetlands, the organic material is mineralized into nutrients which are used by plants for a photosynthetic process. The filtering process can remove up to 80% of nutrients and up to 90% of pathogens, preventing the development of odours and diseases. Water is released into a natural water body or used for irrigation. The advantages of those alternative efficient systems are multiple; implementation with low infrastructure, operation and maintenance costs and no use of energy or chemical products. The sludge can also be processed by drying it into bio-solids or fertilizer.

Impact: What is the impact of the work to date? Specify both the social and the environmental impact of your work

Lake Fúquene located in the Andean mountains of Colombia is one of the most important inland water ecosystems in the country. Home of a large endemic diversity of birds, fishes, reptiles, macro invertebrates and mammals, it is a cornerstone in the ecological and sociological dynamic of the area. It is the water supply for 200,000 people and crucial for cattle, agriculture, fishing and extraction activities. San Miguel de Sema is a town located here, dedicated mainly to dairy farming and agriculture. As the rest of municipalities surrounding the lake, San Miguel de Sema discharges its wastewater in to the lake. Its inhabitants showed high interest into management alternatives aiming at restoring and protecting the lake. Since 2014, the first green filter pilot project in Colombia delivers clean water for domestic uses for the inhabitants or return clean water to the natural water bodies as conservation strategy and an excellent alternative for waste water management in the region.

Financial sustainability plan: How is this initiative financially supported? How will you ensure its financial sustainability long-term?

With the objective to protect aquatic and wetland habitats, synergies among different stakeholders led to the development of the green filter projects. Global Nature Fund (GNF), the German Federal Ministry for Economic Cooperation and Development (BMZ), the German and Swiss companies Kärcher and Sika, Foundation Ursula Merz as well as public utility companies like the Colombian CAR came together for the support of the projects. Of particular importance is the support and enthusiasm of every local partner as well as the involvement of the local community. Cost for establishing a green filter vary strongly between communities and were covered by external bodies as named above to various extends. Low maintenance costs are covered by the municipalities with water cents from the households.

Unique value proposition: What makes your initiative innovative? How does your project differ from other organizations working in the same field?

Its the sum of shared values which make green filters innovative. On one hand the environmental and social aspect of dirt water harming nature and people and to provida a solution for that. In the other hand, provide new habitats for several aquatic species, harmless water for irrigation of crops and gardens. Finally, this is a low technique method. No pumps, no electricity, even no sophisticated mechanics are needed to clean the water. this, at teh end is crucial for the long term success.

Founding story: Share a story about the "Aha!" moment that sparked the beginning of this initiative.

Karcher approached Fundación Humedales and partners in 2012 with the will to launch a project under the title "Clean water for the world". In Fuqene, we saw the problem since years and struggled for a sollution, which might possibly not only solve our problem, but also advance with the situation we knew from many other places in the world. The "Aha!" moment was when we spread the idea of this filter green filter with a presentation on the 14th Living Lakes conference in Nanchang/China in November 2014. After our presentation, a large number of delegates from the 50 countries present approched us and asked the whole thing between financial, technical and management aspects of that technique. This was the point when we suddenly understood that indeed, our solution had the potential to create shared values.

Where did you hear about the Nestlé Creating Shared Value Prize?

  • Upon recommendation from others
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Attachments (3)

BMZ Green Filter Colombia_FH Handbook.pdf

Handbook for the implementation of green filters, by Fundación Humedales.


Article in Journal DUH World about green filters.

GNF_Green Filter article_All about water_sep2015.pdf

Article about green filter in EverythingAboutWater Magazine.


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