Urban farming could make way for greener cities
The majority of the world’s population now lives in urban areas. What if fruits and vegetables were grown closer to where people actually lived? What if fresh tomatoes could be picked up on the way home from work? The idea is more than plausible if the researchers at the Fraunhofer Institute for Environmental, Safety and Energy Technology (UMSICHT) have their way.
Photo of the education center for InFarming’s partner, American firm BrightFarm, at the Manhattan School for Children (NY, USA).
Many urban buildings have flat-topped roofs where greenhouses could be installed, making use of a building's waste heat and treated wastewater. Such systems do not currently exist in Germany, however. UMSICHTs inFarming project, short for integrated farming, is working to develop solutions for urban agriculture.
“These solutions could be implemented soon,” explains UMSICHT Project Manager Volkmar Keuter. “Our goal is to make use of existing buildings for the growing of vegetables.” Many plant varieties are considered suitable for cultivation in city farms like this. “In addition to fruits and vegetables, we’d also like to investigate the cultivation of medicinal plants,” says Keuter.
Reduced land use, better air quality
The advantages of integrated farming include lessening land consumption for agriculture, nearly no transport costs meaning a reduction in emissions, and fresher products as fruits and vegetables are grown where they’re consumed. The waste heat from the house and supplementary semi-transparent solar cells would be sufficient to supply the greenhouses with energy according inFarming’s models.
Water consumption is also minimal, as dirty water is cleaned and then reused for watering in a closed circuit. Multifunctional micro sieves and self-cleaning photocatalyst coatings would ensure the quality of the water. Even nutrients for the plants could be filtered out of rainwater and sewage.
“In our concept we have hydroponic systems,” says Keuter. A thin film of controlled water is enough for the plant to absorb the nutrients. “The advantage is that the yield is up to ten times higher. Soil would also be too heavy for many roofs. This is why we’re working on a system to supply the plant with nutrient solutions.”
Unused space
In Germany alone non-residential buildings comprise 1,200 million square meters of flat roofs. The researchers estimate that on about a quarter of the area could grow herbs and vegetables, meaning that potentially some 28 million tons of CO2 could be taken out of the atmosphere.
The idea of urban agriculture is not new and has been discussed extensively at the international level. Urban, vertical, sky or rooftop farming refer to the various approaches. Designers and architects are working on futuristic green buildings. inFarming would make use of existing structures, however. Still to be determined are the supply chains for locally produced vegetables and herbs.
There are also other questions: Which products are suitable? How is the acceptance of nutrient solutions instead of soil? We want to have only very high-quality vegetables and not mass produced ones,” emphasizes Krause.
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