Boosting circular economy and closing the loop in agriculture: Case study of a small-scale pyrolysis–biochar based system integrated in an olive farm in symbiosis with an olive mill

• Carbon sequestration and soil quality improvement coupled with bioenergy.
• Pyrolysis–biochar system into an olive farm in symbiosis with an olive milling.
• Closed-loop system can be the key to rearrange the farm’s management.
• Exchange the concepts of circular economy.

Carbon sequestration and soil quality improvement coupled with bio-energy generation are important issues to be addressed in agriculture by valorising crop residues and by-products. The aim of this work is to study a pyrolysis–biochar system applied to an olive farm in symbiosis with a 2-phase olive mill. The set-up of a closed-loop productive system is proposed. The results have shown that the valorization of 70.0 t of solid and semi-solid wastes issued from both 10 ha olive grove and milling process can be converted via pyrolysis into 13, 11, 12 t of liquid fuel, biochar and gas fuel, respectively. The liquid and gas fuels can fulfill the olive milling energy needs and produce an electricity surplus of ~13.00 MW hel resulting in an extra income (4000€) if sold to the grid. In the case of solar drying of the raw material, ~30.00 ΜW hel could provide 8900€ per year. A SWOT analysis shows that pyrolysis of agri-residues targeting biochar can fulfill the aim of closing the loop in agriculture and circular economy objectives.