Enhancement of methane production from alkaline pretreated poly (lactic acid) waste by the co-digestion process

Abstract

The objectives of this research were to evaluate the biomethane production yield from the anaerobic co-digestion process and biodegradation potential of the post-consumer plastic waste made from Polylactic acid (PLA). The PLA waste was pretreated with sodium hydroxide (NaOH) and further utilized as a co-digestion substrate, along with organic waste. The potential of alkaline pre-treatment and co-digestion of PLA with food waste and market waste for methane production was investigated. The continuous stirred-tank reactor (CSTR) feed batch was carried out on the laboratory scale. The results from the CSTR test revealed that the utilization of pre-treated PLA as a single substrate could produce biomethane for 148 L/kgVSadded. The co-digestion of pre-treated PLA with market waste could enhance biomethane production yield as high as 282.7 L/kgVSadded. Biomethane production obtained from co-digestion of pre-treated PLA with food waste was 211.6 L/kgVSadded, which was 1.6 times higher than utilizing the food waste alone.