The effect of anaerobic co-fermentation on acidification performance of food waste and cardboard waste

Abstract

The fermentation system with high solid materials for food waste (FW) is uneven in nutrition and easy to produce volatile acid accumulation, which causes the reaction system to acidify and affects the normal operation of fermentation. This study evaluated the effect of the co-substrate percentages (FW:CB = 9:1, FW:CB = 8:2, FW:CB = 7:3) and the initial total solid contents (12%, 15%, 18%) on the co-fermentation acidification performance of FW and cardboard waste (CB). The maximum methane production was obtained when mono-fermenting FW had high solids contents (1.4 L/kg). The methane production increased and then decreased with the increasing percentages of CB. Under the conditions of FW:CB = 8:2, the maximum methane production could reach 3.4 L/kg. The lower methane production (1.8 – 2.5 L/kg) with high percentages of CB (FW:CB = 7:3) was translated into higher yields of caproic acid (up to 26%), which indicated that lower percentages of CB had a stabilization effect due to the higher buffering capacities in co-fermentation. As a result, this study demonstrated new possibilities for using CB percentages to control the production of high added-value biogas in dry co-fermentation of FW. HIGHLIGHTS High-solid anaerobic co-fermentation of food waste and waste cardboard was studied.; Co-fermentation results in rapid degradation and stabilization of amylase.; Anaerobic co-fermentation of waste can adjust the nutritional balance of the system.; Addition of cardboard increases buffer capacity, and methane production is 3.4 L/kg.; Food and cardboard waste co-fermentation are classified as butyric acid fermentation.;

Keywords

• anaerobic co-fermentation
• enzyme
• food waste
• high solid
• volatile acid
• waste cardboard