Scalable Pretreatment Methods And Biomethane Production Of Select Single-use Biodegradable Food Containers - PLA And Fiber Based

Abstract

Due to plastics persistence in the natural environment and its dependence on nonrenewable resources there has been push by consumers for the development of biodegradable and compostable single use plastics. Although there has been an increase in the presence of these materials in the market, there has been a lag in the development of commercial composting facilities that have the ability to process? Treat and process? this new wastestream. There is a strong need for these facilities or alternative treatment methods, as certain certified compostable materials such as poly(lactic) acid (PLA) based containers, are not designed to break down in the natural environment (M. Nazareth et al. 2019), and thus may have negative implications on its ecology, especially marine life. Concurrently, there is a global industrial movement towards the revalorization of wastewater treatment and for the generation of electricity at Wastewater Treatment Plants (WWTPs) through anaerobic digestion, either for exporting electricity to the grid or for developing Net Zero Energy (NZE) out here i think (i dunno what is is ha)]NZE infrastructure. In addition to energy and resource production-potential from wastewater, it has also been shown in the literature (N. Benn et al. 28), and in running WWTPs, that co-digestion of substrates such as food waste; fats, oils, and greases (FOG); and potentially even bioplastics (at variable concentrations and loading rates), may significantly lead to increased biogas production. However, scalable and realistic pretreatment of biodegradable single use containers (PLA, PHA (Polyhydroxyalkanoates), and bagasse fiber) followed by anaerobic co-digestion of these materials with sewage has not yet been identified. Studying this could lead to novel discoveries that open up low-cost and clean energy and waste streams for communities globally. To this date there are also no studies published on the potential negative implications of this alternative degradation pathway, such as the potential for toxicity and any negative biodegradation products that may be produced. This must also be studied before implementation of these novel processing pathways. In this study, the effects of thermochemical hydrolysis at elevated pressures and temperatures (110C - 170C) were investigated on the biochemical methane potential of the material. It was found that external chemical treatment was unnecessary and that using DI water at 120C for 48 in a sealed vessel with a concentration of 100g/L of PLA single-use containers itself made a strong acid at a pH of 1.3 that could be utilized for chemical treatment of fiber based biodegradables, as opposed to adding any external chemicals such as HCL or NaOH for pretreatment.