-The South Holland agri-food sector covers half of the province’s surface, produces six million tons of products with a value of € 5.5 billion annually, and entailed around 16,500 businesses and 103,000 jobs in 2016 (Drift and Metabolic, 2018). The sector is an important driver of prosperity and innovation in the region but produces vast negative environmental externalities. Around one million animals consume 1.3 million tons of cattle feed yearly, and produce immense amounts of manure. Inputs such as soy, fertilizer, antibiotics, and pesticides generate a variety of serious ecological disturbance. Greenhouse horticulture, a key agri-food sector in Zuid-Holland, consumes large amounts of water and energy from fossil sources to produce food, flowers and greenery. In alignment with a dedicated national agenda (Ministerie van I&M, 2016), the province of South Holland therefore seeks for the agri-food sector’s transition towards more circularity. Focus is on a reduced use of natural resources, the closure of nutrient cycles, and the recycling of residual flows. The transition is also strongly associated with more deliberate, wider and higher-quality applications of biomass. Because biomass plays an important role in many plausible production and consumption circles, its use implies great potential for an integrated circular economy. Preconditions in this context are the integration of main and green port economies, the diversification of agricultural production across the region, and new respective urban-rural relations. However, while an increased reliance of economic sectors on biomass is desirable, it is also requires scrutiny. Simultaneous use of bio-based materials for e.g. construction, energy production, and packaging may, for instance, threat food security or lead to the depletion of natural habitats. Any strategy for a circular bio-based economy – one that rests on return flows of biomass residues, often classified as organic waste - therefore needs to incorporate principles that organize the multiple claims on the materials efficiently and fairly.
