Assessment of aging of anaerobic digester paddle-mixer material: experimental studies and long-term numerical simulation.

In this study, experimental tests and numerical simulations (Abaqus) were performed to examine the durability of four impeller materials [steel, polyethylene, polypropylene and glass fiber reinforced polymer (GFRP)] in an anaerobic digester environment. Specimens of these materials were prepared and immersed in a bath containing anaerobic digester liquor while operated at 40 °C for a period of 8 months. Periodically (2, 4, 6 and 8 months) sample specimens were removed from the bath and the tensile strength and elastic modulus were determined.