Polyethylene terephthalate sheet (PET) with a biodegradation promoting additive, provided by ENSO Plastics, was made and evaluated in an anaerobic environment with three different inoculums: landfill leachate, wastewater treatment residue, and liquid from an anaerobic digester. As bioreactors, 125 mL glass bottles with closures were prepared, and test samples, fresh cow manure, and inoculums were placed into the bioreactors. The bioreactors were kept in a 35 ̊C incubator. Gas production from the samples was measured for 90 days. Cellulose samples, prepared as positive controls, showed higher gas production than the other samples, and its biodegradation extent reached 32.4 %, 51.6 % and 36.5 % in each inoculum, respectively. However, PET with additive samples did not show higher gas production than either blank or neat PET in landfill leachate, wastewater treatment residue and anaerobic digester inoculums. Statistical analysis of the gas production data showed that only cellulose was significantly different than the other samples in landfill leachate, wastewater treatment and anaerobic digester inoculums (α=0.05). In conclusion, no significant difference was observed in PET with biodegradation promoting additive in this test environment. According to ENSO Plastics, the cloudiness of the PET sheets made for this experiment indicated insufficient dispersion of the additive: the company states that excellent dispersion is required to enhance biodegradation.
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