Circular economy-based integrated closed-loop farming system: A sensitivity analysis for profit optimization

This study proposes and constructs a model for a closed-loop farming system (CLFS) for pig manure waste reuse under circular economy principles (CEPs) to optimize economic benefits. Pig farming produces waste that harms the ecological environment in Taiwan. However, few studies have focused on pig farming waste within the context of CEPs, where the resource utilization of pig manure waste and CLFS are the main concerns. This study introduces a CLFS with a farming production plan that enhances systematic efficiency and builds a framework for resource reuse, supporting a local living circle. The resource utilization of pig manure waste is integrated into the CLFS, ensuring that the entire pig raising production process operates within the system, maximizing waste utilization to increase economic benefits. A sensitivity analysis is also presented. The results confirm that all counties and municipalities in Taiwan achieved self-sufficiency in pork production, reaching a 100% satisfaction rate for pork demand, and feed prices did not impact the overall CLFS.