Abstract: A loose fill lightweight plastic aggregate for a preassembled drainage line unit. The bead comprises a central portion, at least three legs extending from each of the top and bottom of said central portion, a plurality of channels each defined by adjacent ones of said legs, the width of said legs being greater than the width of said channels. A rib protrides laterally from each of the sides of the central portion. In the drainage unit, the beads maintain a substantial void space for flow of waste water and also provide maximum surface area for bacterial breakdown of sewage wastes.

Abstract: A poultry rearing barn having its floor covered by bedding including a plurality of lightweight expanded polystyrene chips. After use, the dirty chips may be cleaned to remove waste manure and the cleaned chips may be reused again as bedding. Alternatively, the dirty chips and waste manure may be burned to generate electricity.