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New System Uses Natural Processes to Treat Nursery Leachates


The Cleanleach system makes it possible to recover and treat the leachates from nurseries' own irrigation systems for more sustainable container plant production.


The plants used in gardening, landscaping and reforestation are grown in nurseries. In Europe, 127,000 ha are set aside for this activity.

Container plant production facilitates agronomic management, transport and transplanting in the definitive location, but it also generates leachates that cannot be released into the environment because they contain high concentrations of nitrates and sometimes phosphates.

The Cleanleach system makes it possible to return these leachates into the irrigation system and take advantage of the nitrate and phosphate content as fertilizers.

The technology developed by IRTA combines slow horizontal sand filtering of leachates under the container area with constructed wetlands to transform the nitrates into nitrogen gas and render the phosphates less soluble.

The new recirculation and treatment process will lead to the improved use of water and fertilizers. Moreover, better water management at nurseries and the use of natural processes guarantee more sustainable production.

The technology was tested at a pilot plant at the IRTA facilities in Cabrils (El Maresme, Barcelona). Thanks to financing from the European Union’s Eco-Innovation Initiative, two full-scale plants are being built, one in El Maresme (Catalonia) and the other in Croxton Park (United Kingdom). These two plants will be implemented thanks to the participation of two project partners, the bioengineering companies Naturalea and Salix. Another project partner, the company Buresinnova, is developing new applications of the Cleanleach leachate treatment system for use in plant architecture, soilless edible horticulture and gardening.


Photos attached:

-      Poster.pdf: Diagram of how the Cleanleach system works

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-      PlantaPiloto_Cabrils.jpg: Sand filter readings from the Cabrils pilot plant
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Information prepared by the IRTA Communication Department


Cleanleach Project