Economic Analysis of an Irrigation System for Liquid Manure Application

Abstract

Irrigation application of effluent from lagoon based systems is an important aspect of animal manure management in swine rearing facilities. This paper describes a procedure for obtaining least-cost components and operational parameters for an irrigation system used to apply liquid manure. The paper employs propositions from hydraulics—affinity laws and Hazen–Williams formula—to derive statistically estimable relationships between pressure, liquid output, power requirement, and impeller speed of an irrigation system. Coefficient estimates are then used in a spreadsheet based decision support system that employs an optimization program to select the least costly irrigation system. A practical application is showcased through simulation of three hypothetical swine farms. Main findings are that the use of this optimization procedure can result in cost savings for swine growers applying manure by irrigation and that the cost savings potentials increase with the farm size.