Degradability of bioplastics in anaerobic digestion systems and their effects on biogas production: a review.

Organic fraction of the municipal waste (OFMSW) is a valuable resource for biogas production through anaerobic digestion (AD). Bioplastics is widely used in daily activities, especially with food related items and collection bags, and can reach biogas plants through separate collection of OFMSW. PHAs, starch and cellulose based polymers with different compositions can degrade under anaerobic conditions. Cellulose and PHAs can degrade under both mesophilic and thermophilic conditions where, starch blends required thermophilic conditions in general. Other biopolymers, such as the most abundant PLA, are not able to degrade in the time frame of the facilities in most of the cases. Pre-treatment methods through abiotic and bio-augmentation, as well as post treatment methods, such as composting subsequent to AD are encountered as possible solutions for achieving better degradation or safer disposal of these polymers. The post-treatment/pre-disposal of the materials should be further studied as well as the pre-treatment methods. Studies on the effect of additives in biopolymers was not studied widely and requires further investigation. Degradation of biopolymers under AD, biogas production, pre-treatment and post-treatment methods as well as standard methods (or lack thereof) are discussed in detail in this paper, in order to point out to the possible scenarios that can be encountered when bioplastics end up in co-digestion conditions with organic material. [ABSTRACT FROM AUTHOR]