Improving environmental sustainability of food waste using a solar dryer: Analyzing drying kinetics and biogas production potential

•This study examines the drying kinetics of food waste and its impact on biogas production.•Temperature and airflow play a crucial role in the drying kinetics of food waste.•Drying reduces biogas production, minimizing methane emissions and environmental impact.•For sustainability reasons, solar drying can be easily integrated into existing food waste management systems. The present work analyzes the drying kinetics of food waste, focusing on the effects of temperature, airflow and drying on biogas production. The work involves the experimental determination of food waste drying kinetics under controlled environmental conditions, including modeling the curves using a mathematical model. Indirect solar drying experiments of food waste have been performed at different air flow rates (300 m3.h-1 and 150 m3.h-1) and temperature values (40, 50, 60, and 70 °C). The temperature in the drying room was adjusted to the desired level using an auxiliary electric heating system. Energetic and environmental performance metrics of different air flow rate and temperature configurations have also been investigated and presented within the scope of this work. Additionally, an experimental investigation to measure the biogas generated by the fermentation of dried food waste was conducted. It was established that a logarithmic model best captures the drying kinetics, and the temperature and airflow are crucial variables. Increasing the drying temperature from 40 °C to 70 °C for the tests that performed in lower and higher flow rates improved the specific moisture extraction rate as 45.02 % and 130.65 %, respectively. It can also be observed that only phase 2 is present in the drying curve, phases 0 and 1 are absent. Furthermore, drying decreases the generation of biogas, which is primarily composed of methane, a potent greenhouse gas, according to experimental studies.