GNF - Green Filter in Paraguay

Water purification by plant-based purification systems



Plant based purification systems, also known as green filters, are water channels whose water surface is covered by aquatic plants, which have swimming roots. Through metabolism of the plants, organic substances which are in the waste water are degrading. By these plant based purification systems domestic waste water can be cleaned relatively well.


The green filter has been implemented in Paraguay, in a community with about 4,000 inhabitants. The project was run by the south American partner organisation Fundación Moisés Bertoni. The Global Nature Fund (GNF) as well as the Fundación Global Nature (FGN) from Spain shared their knowledge and experiences in the field of green filter systems.


Project implementation

The municipality already used a waste water system, to which 841 households were attached. But there was no intact waste water purification system to treat the domestic waste water, before running into river Salado, giving rise to eutrophication. This again led to hygienic and health problems of the residents, since they use the water from the river for drinking and for washing.

By implementing the green filter project in this region a first step was taken towards spreading this relative simple technology to other towns and to introduce it to local authorities and administrations. Besides just purifying waste water this eco-system does  have some more advantages for the population. In special workshops the local inhabitants were taught how they can use the fibres of the aquatic plants to generate organic fertilizers or even create handicrafts out of them.


Future prospects

In the long run the project aims to improve the water quality of the river Salado and its ecosystem. This is also improving the quality of life of the local population.The successful pilot project shall inspire further communities to implement such an ecological and cheap sewage purification system, easy to handle.

This project is supported by the Deutsche Umwelthilfe and Rapunzel Naturkost from resources of the Hand in Hand-Fund.

Further information about Lagunita Complex, the Living Lakes member in Paraguay, is available at our website.

 Situation before implementation of the greenfilter: Waste water flow uncleaned into the river.
 Construction of the canal for the greenfilter
 Water hyacinths as plants in the greenfilter
 Workshop for students

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March 2009 – June 2010




Deutsche Umwelthilfe and Rapunzel Naturkost from resources of the Hand in Hand-Fund


Fundación Moisés Bertoni