. . "Waste disposal in the ground." . . . . . "State of the art : swine waste production and pretreatment processes"@en . . . . "State of the art: Swine waste production and pretreatment processes" . . . "State of the art swine waste production and pretreatment processes"@en . . "Swine waste production and pretreatment processes"@en . . . . "State-of-the-art : swine waste production and pretreatment processes" . . . "State-of-the-art : Swine waste production and pretreatment processes"@en . . . . . . . . . . . . . "Sewage Purification." . . "Sewage -- Purification." . "Swine." . . "Animal waste." . . "Animal Waste." . "Robert S. Kerr Environmental Research Laboratory." . . "North Carolina State University. Biological and Agricultural Engineering Department." . .