Development of an approach in spatial planning through site selection for symbiotic and circular low-carbon upcycling of industrial wastes

Abstract This study aimed to present spatial planning for the selection of alternative sites in terms of carbon footprint based on waste transport in the installation of facilities that will produce low-carbon solutions for industrial waste. Designed to point out the importance of symbiotic solutions that encourage circular economy practices, the approach offers a novel solution for both reducing global carbon emissions and determining optimal facility locations. A three-stage GIS-based FAHP (Fuzzy Analytic Hierarchy Process) workflow was developed for selecting proper site for a particular industrial symbiosis facility in Türkiye, using Marble Processing Wastewater sludge (MPW) and plastic wastes (PP/PET) as representative materials. In Stage 1, provinces were screened according to their waste potential. Stage 2 involved the development of a 10-factor suitability (spatial index) map, identifying six candidate sites which were compared in Stage 3 based on transport-related CO 2 emissions using Tier-1 factors and ArcGIS Network Analyst routing. The implementation of the proposed method in Stage 3 resulted in ranking the candidate sites, and 56.4% less carbon footprint was determined between the candidate site with highest and the lowest calculated carbon footprint (0.106: GgCO 2 ). Therefore, in site selection works appending the third stage to the GIS-FAHP methodology was suggested as useful approach that enables logistical optimization, thereby reducing not only environmental impacts but also transportation costs. The proposed methodology supports effective waste management, minimizes the environmental–financial burdens of transportation, and promotes sustainable spatial planning in both urban and rural areas. Graphical abstract