Towards quantifying the environmental & economic impacts of integrated organic waste management in a tropical urbanizing ecotourism region.

Given the finite lifespan of traditional landfills, alternative waste management systems are needed to reduce environmental impacts, promote resource recovery, and support a circular economy. This study evaluated the environmental and economic sustainability of four organic waste treatment scenarios in an ecotourism region of Costa Rica: 1) landfill, 2) municipal centralized composting, 3) municipal centralized anaerobic co-digestion (ACD), and 4) ACD in a private cheese factory. The methodology integrated geoprocessing, Life Cycle Assessment (LCA), and Life Cycle Cost Analysis (LCCA). Collection and transportation (C&T) accounted for over 90% of Global Warming Potential (GWP) and Eutrophication Potential across scenarios, representing the main source of inventory uncertainty. Combined C&T and operations revealed that Scenario 1 had the highest Marine Eutrophication Potential (MEP) (1.72E-4 t Neq per ton of waste), while Scenario 2 caused the highest GWP due to co-substrate transport (12.23 t CO2eq per ton of waste), but the lowest Freshwater Eutrophication Potential (FEP) and MEP (1.06E-4 t Peq and -1.02E-4 t Neq per ton of waste, respectively). Scenario 3 minimized GWP (10.44 t CO2eq per ton of waste) but had the highest cost (US$ 131/t), where operating costs were the most sensitive economic factor, requiring the highest financial incentives (US$1,112,955). Conversely, Scenario 4 had the lowest cost (US$ 49/t) and the lowest incentive requirements (US$616,453), with CapEx being the most sensitive factor. Consequently, selecting the most sustainable waste management system in tropical ecotourism regions requires a multi-criteria approach to navigate these trade-offs.