Abstract
Biodegradable plastic (BDP) bags could provide convenience to people who transport and discharge their kitchen waste in community composting devices located at community centers, shopping centers and other sites if the BDP bags could be deposited into the devices together with the kitchen waste. Before putting BDP bags into use, their degradability in such devices must be evaluated. One point of arguments is that some biodegradable fraction of waste may remain in the compost and this may suppress BDP degradation. The purpose of this research is to determine the effect of coexisting substrate on the BDP degradation in compost. Sheets that were cut from BDP plastic bags that are being sold commercially and are made of a PBSA and starch mixture were used as experimental materials. Starch was used as the coexisting substrate. The results of batch and intermittent experiments with different coexisting substrate additions showed that some high concentrations of coexisting substrates suppressed BDP degradation in spite of the presence of sufficient amounts of bacteria.
