BIODEGRADABILITY OF DEGRADABLE PLASTICS EXPOSED TO ANAEROBIC DIGESTED-SLUDGE AND SIMULATED LANDFILL CONDITIONS

The biodegradabilities of various plastics by anaerobic digested sludg e were measured and compared with the biodegradabilities under simulat ed landfill conditions. Bacterial poly(3-hydroxybutyrate-co-3-hydroxyv alerate) (PHB/HV; 92/8, w/w), a natural aliphatic polyester, degraded nearly to completion within 20 days of cultivation by anaerobic digest ed sludge, while synthetic aliphatic polyesters such as poly-lactic ac id, poly(butylene succinate), and poly(butylene succinate-co-ethylene succinate) did not degrade at all in 100 days. Cellophane, which was u sed as a control material, exhibited a similar degradation behavior to PHB/HV. Under simulated landfill conditions, PHB/HV degraded quite we ll within 6 months. Synthetic aliphatic polyesters also showed signifi cant weight losses through 1 year of cultivation. The acidic environme nt inside simulators generated by the degradation of biodegradable foo d wastes which comprised 34% of municipal solid waste seems to cause t he weight loss of synthetic aliphatic polyesters.