Department of Environmental and Life Sciences, Toyohashi University of Technology, Toyohashi, Aichi, 441-8580, Japan.
Department of Environmental and Life Sciences, Toyohashi University of Technology, Toyohashi, Aichi, 441-8580, Japan.
J Environ Manage. 2018 Nov 15;226:476-483. doi: 10.1016/j.jenvman.2018.08.034. Epub 2018 Aug 13.
Because packing bags and disposable items of poly (l-lactic acid) (PLLA) waste are discharged together with other organic waste including garbage, anaerobic co-digestion of PLLA and other organic waste is required. However, because of low hydrolyzability of PLLA products, the chemical hydrolyzability must be improved for PLLA treatment during anaerobic digestion. This study aimed to assess weight-average molecular weight (M) and crystallinity (X), to determine the chemical hydrolyzability of PLLA, for PLLA treatment during anaerobic digestion. Moreover, the possibility of anaerobic co-digestion of the PLLA after improvement of chemical hydrolyzability and other organic waste was also discussed. Detectable methanogenic activity of the mesophilic and thermophilic anaerobic sludges of PLLA occurred in the M range of 6,800 to 16,500, and 6,800 and 38,000, respectively. The methanogenic activity of mesophilic and thermophilic anaerobic sludge was higher with PLLA with a high crystallinity (X = 39.9-46.1%) than with nearly amorphous PLLA (X = 0.3-3.5%). The maximum methanogenic activity of anaerobic sludge using PLLA with an X of approximately 40-45% and with a M of 10,300 and 16,500 for mesophilic and thermophilic anaerobic sludge were 0.013 gCOD·gVS·d and 0.13 gCOD·gVS·d, respectively. A survey on the possibility of anaerobic co-digestion of PLLA after improvement in chemical hydrolyzability based on M and X and organic wastes revealed that thermophilic conditions at 55 °C are more advantageous than mesophilic conditions at 37 °C.
由于聚（L-乳酸）（PLLA）包装袋和一次性物品与包括垃圾在内的其他有机废物一起排放，因此需要对 PLLA 和其他有机废物进行厌氧共消化。然而，由于 PLLA 产品的水解性低，因此必须提高 PLLA 在厌氧消化过程中的化学水解性。本研究旨在评估重均分子量（M）和结晶度（X），以确定 PLLA 在厌氧消化过程中的化学水解性。此外，还讨论了在提高化学水解性和其他有机废物后进行 PLLA 与其他有机废物的厌氧共消化的可能性。可检测到中温和高温厌氧污泥的产甲烷活性分别出现在 PLLA 的 M 值为 6800 到 16500 和 6800 到 38000 的范围内。中温和高温厌氧污泥的产甲烷活性均较高，结晶度较高（X=39.9-46.1%）的 PLLA 比几乎无定形 PLLA（X=0.3-3.5%）高。X 值约为 40-45%、M 值为 10300 和 16500 的中温和高温厌氧污泥中使用 PLLA 的最大产甲烷活性分别为 0.013 gCOD·gVS·d 和 0.13 gCOD·gVS·d。基于 M 和 X 以及有机废物对改善化学水解性后 PLLA 进行厌氧共消化的可能性进行了调查，结果表明 55°C 的高温条件比 37°C 的中温条件更有利。
