An economically and ecologically sound manure treatment and application system

Abstract

F uture operation of concentrated animal feeding operations will require improved waste management strategies following more stringent regulations currently proposed by the US Environmental Protection Agency, especially regarding odor and nutrient management. The Livestock and Urban Waste Research Team at Illinois State University has developed a systems approach for treating liquid swine manure and land applying the separated effluent that meets these criteria. The solid/liquid separation system removes 98+% of the settleable solids, 98+% of the total suspended solids, 50+% of the nitrogen (N), and 90+% of the phosphorous (P) from raw slurry, and changes the N:P ratio from 4:1 to 20:1. The cost for separation plus irrigation of the separated effluent is less than 1.0¢ per raw gallon of slurry, comparable to current costs for direct land injection of unprocessed slurry. The separated solids portion can be economically composted or hauled off-farm for land application. Center pivot or surface irrigation is low cost (0.1¢/gallon) but may or may not contribute to nonpoint source pollution. A revitalized concept, controlled tile drainage, has been modified by the Livestock and Urban Waste Research Team to function as a subsurface irrigation system for separated effluent. Subsurface irrigation may or may not contribute to nonpoint …