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Innovative approaches to turn agricultural waste into ecological and economic assets

Periodic Reporting for period 3 - NoAW (Innovative approaches to turn agricultural waste into ecological and economic assets)

Reporting period: 2019-10-01 to 2021-01-31

Agricultural residues represent a huge pool of untapped biomass (50% of fresh harvested crops) that may even represent economic and environmental burdens.
Driven by a near zero-waste goal and supported by 32 transdisciplinary academic and private partners from Europe and China, NoAW aimed to generate innovative eco-efficient approaches to convert this growing amount of human-produced agricultural waste into eco-efficient bioenergy and biobased products with direct benefits for the environment, economy and consumers (NoAW’s ID in Fig.1 and 2).
To support the environmental benefits of the developed scientific and technical innovations on agro-waste conversion at different TRLs, a holistic life cycle thinking was developed in the light of regional and seasonal specificities, not forgetting risks emerging from a potential circular biological and chemical contaminant accumulation, and opportunities generated by organic agriculture.
Via extensive exchanges, all agriculture chain stakeholders were involved in a territorial perspective, to develop innovative eco-design and hybrid assessment tools of circular agro-waste management strategies.
In parallel, breakthrough knowledge on agro-waste molecular complexity and heterogeneity was devoted to upgrade the most widespread mature waste conversion technology, anaerobic digestion, and to create synergistic cascading processes, to fully convert agricultural residues into high added-value bioenergy, biofertilizers and biochemicals (Fig.3) able to substitute oil-based equivalents.
To fast-track NoAW strategies, the complexity of potentially new, cross-sector business clusters was clarified to develop new business concepts and stakeholder platforms for cross-chain valorization on a territorial and seasonal basis (Fig. 4).
NoAW’s solution is a cascading biorefinery of agricultural residues from livestock farming, fruits, vegetables, cereal and wine sectors. To enhance anaerobic digestion, a wet explosion process (AD booster pre-treatment) was developed to degrade the recalcitrant lignin of ligno-cellulosic residues into accessible substrate in subsequent processes. Then, a 2-step anaerobic digestion process has been developed (Fig.5) to produce biogas (H2, CH4, CO2) as well as volatile fatty acids (VFAs) and nutrient rich digestate. The biogas has been upgraded by microbial electrosynthesis into biomethane and biohythane for use as an automotive biofuel or to be injected into the natural gas grid. The safe use of the digestate and nutrient load was optimized in a Bavarian farm with a Near Infra-Red Technology (Fig.6). The volatile fatty acids were used to produce polyhydroxyalkanoates (PHA) able to partially substitute oil-based plastics (Fig.7) and the final packaging materials were formulated with lignocellulosic fillers and antioxidants from winery waste. Other cascading options were explored, most of them successfully, to valorise winery, fruit & vegetable wastes, digestate and VFAs (Fig.8 and 9). Based on NoAW’s findings, a whole technology chain was elaborated with quantified positive environmental benefits and fitting business models for upscaled industrial practice.
Supported by a large international stakeholders platform, agro-waste management strategies were both driven and evaluated by life cycle analysis coupled to territorial metabolism and multi-criteria decision analysis. The developed decision-support tool was successfully used to support NoAW’s concept (Fig.10) and its applicability at regional level. A Geographic Information System tool was developed for mapping waste management, and new practices for handling vine shoots have been adopted by winegrowers in Serbia.
Outcomes have been presented in stakeholder events successfully organized in Brussels, Italy, China and France. Overall, more than 50 scientific papers as well as many dissemination actions have reached worldwide over 40000 stakeholders, who have been actively mobilised all along the project.
The resulting NoAW solution is a robust toolbox of imbricated technologies able to convert a wide range of agricultural residues into high added-value biogas, biochemicals and biodegradable plastic, while overcoming residues’ complexity, seasonality and regionality. NoAW experimental platforms increase biogas production and decrease PHA cost offering a larger PHA market, with significant economic gain compared to biogas.
The developed cascading approach (residues biorefineries) enables to fully valorize the residues into new bio-based products using waste and side streams instead of virgin oil or crop materials and favoring decentralized production facilities, for new income and employment opportunities in rural areas.
Using anaerobic digestion to treat manure, nitrogen availability is increased by 5-20%, which can reduce mineral fertilizer use by 10%, a decrease of 3-5 million tons of CO2-eq./year. A local and full-scale case study of AD nutrient delivery optimization replaces the use of mineral fertilizers and closes the loop for net energy production (biogas), while providing technical data to extend nutrient and energy balance at territorial scale.
By providing a sustainable alternative to conventional plastic through innovative processes (microbial mixed cultures, photofermentation) and improved functionalities (ex. fibres/PHA composites) NoAW helps solving persistent plastic pollution by offering materials with zero risk of microparticle dispersion into nature.
NoAW’s solution contributes to the 20% target of renewable energy, to reduce global warming as well as plastic particles pollution and offers additional incomes to farmers, eco-efficient substitutes to users of oil-based plastic and gas, as well as safe eco-friendly product alternatives to citizens.
NoAW concluded that such circular and less polluting alternatives to fossil-derived plastics can hardly compete on cost-price if externalities like pollution are not counted as high volume production or financial support are not provided. Since the European Renewable Plastics directive prioritizes fossils plastics recycling over biodegradability as final end-of-life options, NoAW recommends applications where biodegradation is a key environmental and economic advantage such as fertilizer coating or agricultural plastics, or when the recycling priorities are not applicable such as for horticulture pots.
A Multiple Criteria Evaluation has contributed to the development of agricultural waste management strategies including product, farm and region levels to reach a broader group of stakeholders. NoAW has revealed that many agro-waste initiatives are vulnerable to market situation and cooperation. Recommendations to stimulate eco-sustainable industrial ecology solutions were shared with a large range of stakeholders, including policy makers. NoAW is continuing to actively foster stakeholder cooperation and exchange through the stakeholders platform.
Fig. 07 - Pilot plant for H2, CH4 and PHA prod. from manure-straw-grass-silage (INNOVEN, Verona, IT)
Fig. 10 - Decision support used when choosing options between technologies
Fig. 05 - Pilot plant dedicated to H2 and CH4 production from winery waste (INRAE, Narbonne, FR)
Fig. 03 - Development of an agricultural residue refinery centred on anaerobic digestion (WP3 & WP4)
Fig. 06 - Nitrogen load distribution on fields, assessed by online Near Infra-Red Tech.
Fig. 09 - Cascading activities based on extraction of bio-active molecules from winery waste
Fig. 02 - The Sino-European NoAW project’s consortium
Fig. 01- ID card of the project
Fig. 04 - NoAW’s WPs structure
Fig. 08 - Summary of WP4 activities