More circularity through cross-overs between different sectors

Published on
June 13, 2022

A residual flow of one sector can be a resource for another sector. A better-known example of this is connecting aquaculture and horticulture: the waste water from the fish can be reused as a nutrient solution for the plants in the greenhouse. The Business Unit Greenhouse Horticulture and Flower Bulbs of Wageningen University & Research is investigating whether there are more circular cross-overs that have potential, both within and outside the agricultural sector.

In a circular economy, residual flows are reused. This does not always have to be done within the same sector. Connecting sectors could create new cycles that increase overall circularity. To realize these cross-overs, new business cases have to be developed that accommodate, among other things, the needs of both sectors. WUR is investigating with which other sectors greenhouse horticulture can be linked and has already looked into cross-overs with aquaculture, pig farming and mushroom cultivation during a so called Knowledge Base research project. The potential of a cross-over between a vertical farm and urban waste flows was also investigated.

For the cross-over with pig farming, for example, we are looking at how manure can be converted into usable fertilizers and CO2 for the greenhouse. But also how used substrate from the greenhouse could serve as enrichment inside the pig-sheds.

For the cross-over between the mushroom sector and horticulture we look at the use of residual flows from horticulture (plant biomass or substrate) as a substrate for the cultivation of mushrooms and the use of spent mushroom substrate as an additive to growing medium for horticulture in order to increase plant resilience. Another possibility is the use of CO2 from mushroom cultivation in greenhouses. To further develop this crossover, a new PPP project will start this year.

WUR is not only looking at cross/overs within greenhouse horticulture: new connections are also possible with other sectors. A workshop was recently organized at the Circular@WUR conference to gather more ideas and inspiration together with external experts. Companies that would also like to contribute ideas and participate in the topic of cross-overs are very welcome to get in touch via

The Knowledge Base research falls under the KB-Program: Circular and Climate Neutral, which is financed by the Ministry of Agriculture, Nature and Food Quality. The Business Unit Greenhouse Horticulture of Wageningen University & Research is leading the overall research project (KB-34-007-007) that focuses on the transition to a circular greenhouse horticulture sector.