Development of a decision support methodology for the design of animal waste management strategies to achieve regional environmental objectives

Management of waste from confined animal feeding operations is important. While anaerobic lagoons and sprayfields are currently used for treatment, recent administrative initiatives call for their replacement. This decision necessitated the cost and treatment-effectiveness characterization of alternative technologies. However, due to variations in farm characteristics (e.g., size, location), identification of the most cost-effective combination of treatment technologies to achieve collective environmental goals requires an integrated approach. The objective of this research was to develop a regional management decision-support framework to assist policy-makers, planners, and farmers in making cost effective lagoon replacement decisions to achieve desired treatment and public protection goals. A major component of the framework is a cost and treatment efficiency assessment tool to evaluate alternative animal waste treatment technologies for individual farms. Outputs from the assessment tool, together with geospatial data, feed into the regional management component of the framework, which consists of several formal optimization techniques that assist in the search for good decisions. Among these techniques are an optimization engine that can be used to find management strategies that meet cost and environmental targets, and a method for efficiently generating alternatives (MGA). Management alternatives have similar cost and environmental performance but may behave differently for unmodeled objectives. Finally, the regional management framework includes an uncertainty analysis component that allows the evaluation of alternatives while considering the uncertainty in model inputs. The decision-support framework was demonstrated through an illustrative example; the waste management of swine farms in the Lower Neuse River watershed in eastern North Carolina to achieve a 30% reduction in nitrogen loading. Results show that (1) a regional management approach is essential for achieving cost savings, (2) there is significant flexibility in meeting the nitrogen reduction and cost targets, (3) consideration of uncertainty may lead to the selection of a different solution, (4) the decision support framework can be used successfully to address a range of concerns, including but not limited to cost, risk, equity, and uncertainty.