LIFE BioTHOP – BioTwine HOP waste transformation into novel product assortments for Packaging and Horticulture Sector
Hop training systems in Europe are based on wire or polypropylene (PP) twine trellises, usually pinched for about 6-7 meters above the ground on a regular arrangement of wooden or concrete poles. Roughly 5 dt/ha of steel cord and 5.5 dt/ha of steel barbed wire are consumed for wire netting, or 45 km of PP twines/ha for twining, each season. Both mentioned practices are far from EU’s environmental policy objectives, since the after-harvest biomass cannot be properly composted, recycled or landfilled. Unfortunately, for hop agro waste, which yields up to 15 tons/ha (fresh matter) per season, the most frequent practice is still uncontrollable burning. In response to the problem described, BioTHOP project thus indorses a new circular economy for improved hop waste management, that combines alternative bioplastic twine materials based on poly(lactic acid) (PLA), with ability to be converted into novel feedstock for 100% biodegradable, compostable and recyclable packaging & horticulture product accessories. This project was finished in 2022 and has a total project budget of 1.9 M€
Within European Union alone, 2,600 farms are engaged in a hop-growing industry, covering the 26,500 hectares, (60% of the total surface area used for a hop-growing worldwide), with an annual hop production capacity of over 50,000 tons. The most firmly anchored practice for hop growing management is still the use of fossil-based polypropylene (PP) twines, which on one hand provides an excellent mechanical performability, but on other hand the periodic entry of non-degradable plastics, pose a serious burden to the environment. Furthermore, hop cones are considered to be the only useful material of the hop plant, while the remaining biomass (bines & leaves) because of the plastic twine residues, is currently discarded as a non-compostable waste, typically sent to landfills or incineration plants. To solve this environmental problem, BioTHOP proposed a paradigm shift in hop-growing industry by establishing a novel circular approach, demonstrated by: 1.) 100% elimination of fossil-based plastics by introducing biocompostable and biodegradable polymer twines based on polylactic acid (PLA), allowing ecologically sustainable hop-growing practice. 2.) The viability performance of modified PLA twines to be utilised in a hop growing sector, with mechanical characteristics equal to traditional PP twines, improved resistibility towards the weathering conditions and facilitated manipulation for farmers. 3.) The compostability allowance of harvested hop biomass with PLA fractions to be returned on agro-fields in the form of organic fertilizers. 4.) The feasibility of turning the harvested hop waste (organic biomass – leaves and bines with PLA leftovers) into new valuable feedstock resources, such as pulp fibre, reinforcing filler additives and biocomposite compounds, through the most extended manufacturing technologies (pulp moulding, injection moulding & extrusion compounding). 5.) The production and validation of economically-competitive bioplastic products made of recovered hop wastes for packaging and horticulture sector. 6.) The replicability and transferability of project results on three-fold level: (1) other transformation processes (extrusion blow moulding), (2) new applications (bio-films), and (3) transregional, and the demonstrative replication will be implemented in at least 5 other EU States: Austria, Czech Republic, Croatia, Spain & Germany).