Conference Agenda

The research financed by the Cariverona Foundation aims to develop a hydrothermal carbonization reactor for the treatment of olive residues to be used as a bioactive compound. Two different biomasses were used: olive pomace and olive tree pruning foliage. After a complete characterization, the biomasses were subjected to thermal treatment at four temperature levels: 150, 180, 210, and 230°C, with a water-to-biomass ratio of 30:1. Each test time was one hour after reaching the setpoint temperature. The resulting liquid fractions were characterized through pH measurement and antioxidant activity assessments. Subsequently, they were used for germination tests on watercress and basil and for phytotoxicity tests on olive leaves. The results show that the phytotoxic effect is most evident starting from the products treated at 210°C. The liquid of the 150°C tests, on the other hand, show a very low phytotoxic, while the pyroligneous acid produced by the 180°C test shows the best compromise between biocidal and bio-stimulant effect. In conclusion, the experiment highlighted the strong potential of the pyroligneous acids as seed-dressing agents, which could be exploited in nursery or open field conditions for the control of certain plant diseases. This effect, however, needs to be validated by long-term field experimentation.

Yanmar R&D Europe developed a small-scale gasifier designed to convert pruning residues into energy, biochar, and wood vinegar (WV), thereby generating valuable on-farm resources within a circular management framework. The present study aimed to evaluate, under field conditions, the agronomic effects of integrating biochar and WV in open-field cultivation of tomato. A strip-plot experimental design was implemented with four treatments: (i) soil amended with biochar at 15 t ha⁻¹; (ii) biochar combined with WV (15 t ha⁻¹ + 400 mL hL⁻¹); (iii) WV alone (400 mL hL⁻¹); (iv) untreated (control). Commercial biochar was applied once, while WV from gasification of pruning residues was applied weekly from June to September. Measurements were conducted from June to September 2024. The assessed parameters included NDVI, chlorophyll index, number of flowers, number and weight of fruits. For each treatment, 30 plants were randomly distributed in the field and monitored throughout the trial. The combined application of biochar and WV resulted in the highest agronomic performance. Biochar alone also enhanced yield in comparison with control and WV alone, whereas WV alone showed good effects in the number of flowers. Overall, the integrated application of products demonstrated greater benefits than individual treatments in open-field tomato production.

Seaweeds’ CO₂ sequestration capacity and roles in blue carbon strategies are attracting global attention. In 2024, Japan formally reported seaweed-based CO₂ fixation to the United Nations, accelerating efforts toward large-scale offshore cultivation. However, the substantial energy demands associated with seaweed production raise concerns regarding the net sustainability of this approach.

Here, we present an energy-efficient and high-performance methane fermentation system designed to valorize a portion of the cultivated seaweed for renewable energy recovery. Unlike in conventional processes, undried seaweed biomass was directly subjected to mesophilic anaerobic digestion, eliminating energy-intensive drying. To enhance biodegradability and methane yield, we applied microbial pretreatment using enrichment cultures capable of degrading alginate, mannitol, and cellulose, the major structural and storage polysaccharides in brown seaweeds.

This integrated strategy achieved high gas conversion efficiency while maintaining process stability. Furthermore, the influence of salinity during pretreatment was systematically evaluated to ensure practical applicability under realistic cultivation conditions.

Our findings demonstrate a viable pathway to couple blue carbon cultivation with renewable bioenergy production, improving the overall energy balance of large-scale seaweed utilization systems.

Rewetting of drained peatlands to reduce GHG emissions is an issue worldwide and affects more than 50 million hectares in the EU alone. This poses enormous challenges for agriculture until year 2045. However, it also offers great potential for biomass production as this land can no longer be used for common crop production. Therefore, ATB develops new process lines for the production of grass-like biomass grown on rewetted peatland to combine climate goals with agricultural income. Using a twin-screw extruder, peatland biomass can be processed e.g. to fibers for insulation and paper, it can be used for horticultural growing substrates or as a biogas feedstock. Combining alkaline treatment with extrusion enables a controlled partial transformation of peatland biomass into artificial humic substances while preserving carbon and fibers. This process is currently further developed for the production of artificial peat. Some of these process chains are already tested on practice scale with partners from industry. For example, on basis of a novel continuous thermo-mechanical pulping technology developed at ATB, mixtures of fibers from peatland biomass and virgin pulp have been produced and successfully tested in a ratio of 1:2 for paper and 2:1 for molded pulp production.

Bioethanol is a renewable fuel derived from agricultural residues that could employ agricultural wastes to produce biofuels as a viable energy alternative while reducing environmental pollution. The aim of this study is to characterize ethanol production using corncobs and cassava peels, aiming to optimize fermentation parameters and evaluate the fuel's physicochemical properties. The experimental procedure included acid pre-treatment of lignocellulosic biomass at varying concentrations, followed by hydrolysis and fermentation. Sixteen experimental runs were performed, with cassava peel proportions ranging from 0–100%, acid concentrations between 1.0–2.0 mol, yeast loading from 20–50 g, and fermentation times adjusted between 48–72 hours. Ethanol yield was measured, and fuel properties such as density, viscosity, cloud point, pour point, and flash point were analyzed for energy suitability. Results indicated that yeast concentration, cassava peel ratio, acid hydrolysis, and fermentation duration significantly affected ethanol yield and quality. The optimal conditions for production were identified as 45 g of yeast, 100% cassava peel, 1.0 mol. of acid, and 72 hours of fermentation, yielding 12-26 mL of ethanol. Obtained bioethanol exhibited desirable characteristics, confirming that corncobs and cassava peels are promising low-cost feedstock for sustainable energy applications, presenting a viable alternative to fossil fuels.

Pre-treatment of feedstocks prior to anaerobic digestion is a well-established strategy to enhance biogas yields and improve digestate quality. Mechanical separation redistributes nutrients, leading to phosphorus (P) accumulation in the solid fraction and nitrogen (N) in the liquid fraction, increasing the risk of soil and water pollution when land applied. Struvite (NH₄PO₄·6H₂O) precipitation offers a promising route to simultaneously recover P and N as a slow-release fertilizer.

In light of the recent EU Directive 288/2026, which authorizes the use of RENURE products beyond the 170 kg N ha⁻¹ yr⁻¹ limit set by the Nitrates Directive 91/676/EEC, optimizing nutrient recovery from livestock waste has become increasingly strategic. This study investigates the effects of physical and enzymatic pretreatments on biogas production and organic P solubilization, enhancing its transfer to the liquid fraction and subsequent struvite precipitation.

Hydrodynamic cavitation and enzymatic treatments, including phosphatase and phytase, were evaluated through laboratory batch tests following UNI/TS 11703:2018 guidelines. The recovered minerals were characterized for purity and carbon content. Results identify the most effective pretreatment strategies to maximize nutrient recovery and support the development of RENURE-compliant fertilizers.

This work was funded by the European Union’s Horizon Europe programme under the ECONUTRI project (Grant Agreement No. 101081858).