Life Cycle Assessment of circular economy strategies for the eco-design of ceramic bricks incorporating olive and wine residues: Advancing sustainability through agro-industrial byproducts

The integration of circular economy principles into industrial processes is increasingly recognized as essential for addressing the dual challenge of environmental degradation and finite resource availability. In particular, the reuse of agri-food byproducts represents a key opportunity to reduce the environmental footprint of production systems, as well as promoting waste valorization. Olive mill wastewater (OMWW) and waste pomace (WP) from wine industry, two abundant waste streams from Mediterranean agriculture, are often difficult to manage due to their high organic load and seasonal variability. This study aims to evaluate the environmental performance of ceramic facing bricks incorporating OMWW and WP through a cradle-to-gate Life Cycle Assessment (LCA), comparing them with conventional bricks. Furthermore, a sensitivity analysis has been implemented, to evaluate the maximum break-even transport distances within which the analyzed circular economy strategies guarantee an environmental benefit and therefore a real applicability. Results show that incorporating 200 l of OMWW and 65 kg of WP per functional unit leads to significant reductions across multiple impact categories. Notably, the Global warming potential (GWP) is reduced by 8 % for OMWW and 37 % for WP, while Acidification (A) decreases by 19 % and 35 %, respectively. The calculated break-even distances are 641 km for OMWW and 9015 km for WP in the worst-case scenario, in terms of maximum truck load. For longer distances, the additional impacts due to transport would cancel out the benefits deriving from waste valorization. These findings support the integration of agricultural residues into ceramic production as a viable strategy for enhancing sustainability.