Keywords: animal waste management, environmental systems analysis, swine waste, pigs, environmental objectives, regional objectives, anaerobic lagoons, lagoon replacement, mixed–integer linear programming, MILP, modelling, cost, nutrient release, risk, nitrogen reduction
Design of animal waste management strategies to achieve regional environmental objectives
Anaerobic lagoons are currently used for swine waste management in many countries, worldwide. Recent initiatives, for example in North Carolina, USA, calling for their replacement have increased the need for characterisation of the cost and treatment effectiveness of each alternative. Identification of the most effective solution to achieve collective environmental targets needs an integrated approach that examines and searches among technology alternatives at all farms simultaneously. In this research, management strategies were developed that will aid policy makers, planners, and farmers in making cost effective lagoon replacement decisions to achieve desired treatment and public protection goals. A mixed–integer linear programming model that allows the examination of management scenarios for a region was developed and used to search for good solutions with respect to various goals (cost, nutrient release and risk). With a target of 30% reduction in nitrogen for a case study watershed, large difference in cost (a more than three–fold reduction in cost was achieved) and risk resulted for the management scenarios.