Assessment of Petroleum-Based Plastic and Bioplastics Degradation Using Anaerobic Digestion

Abstract

Bioplastics have emerged as a viable alternative to traditional petroleum-based plastic (PET). Three of the most common bioplastic polymers are polyhydroxybutyrate-valerate (PHBV), polylactide (PLA), and cellulose-based bioplastic (CBB). This study assessed biodegradation through anaerobic digestion (AD) of these three bioplastics and PET digested with food waste (FW) at mesophilic (35 °C) and thermophilic (55 °C) temperatures. The four plastic types were digested with FW in triplicate batch reactors. Additionally, two blank treatments (inoculum-only) and two PHBV treatments (with FW + inoculum and inoculum-only) were digested at 35 and 55 °C. The PHBV treatment without FW at 35 °C (PHBV-35) produced the most methane (CH4) normalized by the volatile solids (VS) of the bioplastics over the 104-day experimental period (271 mL CH4/g VS). Most bioplastics had more CH4 production than PET when normalized by digester volume or gram substrate added, with the PLA-FW-55 (5.80 m3 CH4/m3), PHBV-FW-55 (2.29 m3 CH4/m3), and PHBV-55 (4.05 m3 CH4/m3) having 848,275 and 561%, respectively, more CH4 production than the PET treatment. The scanning electron microscopy (SEM) showed full degradation of PHBV pellets after AD. The results show that when PHBV is used as bioplastic, it can be degraded with energy production through AD.

El compostaje de cáscara de Musa paradisiaca L. para la producción de biogás y biometano como estrategia de preservación de la salud ambiental

“…Como se mencionó anteriormente, los dos componentes principales del biogás son el metano CH4 y el dióxido de carbono CO2, que van acompañados de otras impurezas como nitrógeno, oxígeno, hidrógeno, sulfuro de hidrógeno y amoníaco. La composición típica del volumen de biogás es 50-75 % de metano, 25-45 % de CO2, 2-7 % de vapor de agua, menos del 2% de amoníaco y menos del 1% de sulfuro de hidrógeno (Nachod et al, 2021). Esta composición es generalmente adecuada para aplicaciones menos exigentes, como la generación de calor y electricidad (Zupancic et al, 2022).…”

Anaerobic Biodegradability of Commercial Bioplastic Products: Systematic Bibliographic Analysis and Critical Assessment of the Latest Advances

“…ISR = 1 (VS basis). Solids content in the reactor: 7.22% TS 104 271 SEM [ 142 ] PHBV 0.1–0.25 mm 36 Anaerobic aqueous conditions ISO 14853; working V = 1 L; 1 g TS/L inoculum + 150 mg/L test material 77 81.2 Biogas [ 123 ] PHBV 0.1–0.25 mm 36 Anaerobic standard test conditions—ISO 14852; polymer = 1 g VS/L 77 480.1 76.4 Biogas …”

Current Status and Review of Waste-to-Biogas Conversion for Selected European Countries and Worldwide

“…As mentioned previously, the two main components of biogas are methane CH 4 and carbon dioxide CO 2 , which are accompanied by other impurities such as nitrogen N 2 , oxygen O 2 , hydrogen H 2 , hydrogen sulphide H 2 S and ammonia NH 3 . The typical biogas volume composition is 50-75% methane, 25-45% CO 2 , 2-7% water vapor, less than 2% ammonia and less than 1% hydrogen sulphide [101]. This composition is generally suitable for less demanding applications such as generating heat and electricity at the place of production, where only minimal upgrading is required.…”

“…Its positive properties include a short life cycle, high biological productivity and growth rate, survivability in various climatic zones of the globe and low demands regarding the quality of the water environment [100]. Research on anaerobic degradation of bioplastics is ongoing and, so far, the results have shown that the most common bioplastic polymers, poly(3-hydroxybutyrateco-3-hydroxyvalerate) (PHBV), can be degraded with energy production through AD [101].…”