Examining the perspectives of using manure from livestock farms as fertilizer to crop fields based on a realistic simulation

Intensive livestock production has a negative environmental impact by producing large amounts of animal dejections, which, if not properly managed, can contaminate nearby water bodies with nutrient excess. However, if the animal manure could be transferred efficiently to nearby crops and used as a fertilizer for the plants, pollution/contamination would be mitigated, transforming manure from a waste to a resource. This valorization of manure from waste to a resource falls within the circular economy principles, but the transportation of manure also comes at an environmental and economic cost. It is a single-objective optimization problem regarding finding the best solution for the logistics process of satisfying nutrient crops needs through livestock manure. This paper uses a centralized optimal algorithm (COA) to solve the problem, based on a realistic simulator that considers numerous real-world constraints that related work has not yet addressed. Implementation and evaluation of this method have been carried out based on extensive geolocalized data from Catalonia (Spain), one of the densest European farming regions, as a case study. The findings show that the use of treatment units in pig farms is not profitable, while applying treatment units on selected cow farms for composting manure has its merits, under an intelligent choice of cow farms. Finally, a comparison of our findings with those of two similar studies in Hangzhou, China and Minnesota, USA, are performed.