Characterization of Fruits and Vegetables Waste Generated at a Central Horticultural Wholesaler: A Case Study for Energy Production Via Biogas

Abstract

CEASAs (wholesaler food supply centers) are strategically located throughout the Brazilian territory. However, food circulation leads to a high generation of fruit and vegetable waste. CEASA-Maracanaú (Ceará state, Brazil) is an example of this, sending around 17 tons of organic waste to the landfill each day without categorization. An environmentally friendly option to reuse fruit and vegetable wasted (FVW) at CEASA-Maracanaú is using it as a substrate in methane production through anaerobic digestion, which requires a detailed quality and quantity characterization. This study aimed to characterize the FVW generated at CEASA-Maracanaú to evaluate its biomethane potential and estimate energy recovery. To characterize the residue, questionnaires were sent to 1,200 permit holders. The results pointed to a residue composed of orange (42.0%), onion (7.7%), corn (5.5%), papaya (5.4%), avocado (4.8%), watermelon (3.4%), banana (3.0%), melon (3.1%), potato (3.0%), pineapple (3.1%), cabbage (2.4%), guava (1.2%), and tomato (1.0%), among others. This composition was crushed and characterized in terms of chemical oxygen demand (138.13 ± 12.4 gCOD/kgFVW). Biomethane potential tests of crushed residue was 275 NmLCH4/gCOD or 313 NmLCH4/gVS, resulting in 79.3% biodegradability. From this potential, it is estimated that FVW from CEASA-Maracanaú yields a methane-based energy recovery of up to 373 KW of thermic power. As a result, it is possible to meet 86% energy demand of CEASA-Maracanaú during the rush-hour (5:30 pm to 8:30 pm) rate by employing the energy recovered from the daily accumulated biogas.