Valorization of fruit and vegetable waste for biofertilizer and biogas

Abstract

AbstractThe ubiquity of irrational disposal practices for fruit and vegetable waste (FVW) poses prohibitive environmental and economic liability. Anaerobic digestion of fruit and vegetable residues into biofertilizer is a potential solution to reduce environmental pollution and improve soil nutrition. High carbon and low nitrogen content is the main challenge in the bioprocessing of FVWs. In such cases, FVWs is co‐digested with another eco‐waste, the slaughterhouse wastewater (SWW). The issues of abattoir waste disposal are a serious threat to the societal health and hygiene. Interestingly, SWW is a house of mixed microorganisms which release enzymes for anaerobic digestion. In our present study, a two‐stage digestion process, that is, anaerobic digestion followed aerobic digestion using Trichoderma reesei is carried out under optimized conditions for enhanced biofertilizer formation. Each stage was completed in 15 days, total digestion time being 1 month. Biogas generated during the anaerobic process is 16 L/kg for fruit wastes (FWs) and 13.2 L/kg for vegetable wastes (VWs). Significant decrease in lignin up to 64% in case of FWs and 70% in case of VWs helped in cellulose degradation. The FVWs are finally reduced to a potential value‐added biofertilizer with 10–11 C: N ratio.Practical ApplicationsStringent wastes like fruit and vegetable waste (FVW) as well as the slaughterhouse waste were considered for bioremediation and value‐added application. A simple, rapid, unique, and easy to scale‐up technique was envisaged for conversion of FVWs into potential biofertilizer through two‐stage co‐digestion. The studies conducted will be useful for FVW management at household as well as industrial level.