Accelerating Food Waste Composting Course with Biodrying and Maturity Process: A Pilot Study
Liqing Xin, Xiangru Li, Feng Bi, Xiangrui Yan, Haoshu Wang, Weixiang Wu
Abstract
Biodrying and maturity (B&M) is a promising method of processing food waste (FW) into reusable products by rapidly removing water and accelerating material maturation. However, the potential mechanism of biodrying-accelerated maturation has not been revealed systematically. Here, a continuous experiment was performed to investigate the effects of auxiliary measures on B&M performance and the relationships among water removal, bioheat generation/utilization, and material maturation during the B&M process. The results showed that rapid maturity could be achieved within 15 days under optimal conditions: ventilation frequency of 10/20 min (on/off), turning frequency of three times per day, and intelligent heating, with a germination index of 94.28% and 2.8 times increase in low calorific value. The proper air flow and high matrix temperature could be maintained by reasonably regulating ventilation and turning frequencies with an intelligent heating mode, thereby synergistically enhancing water evaporation and bioheat generation. Analyses of the ideal energy–water balance suggested that bioheat (ΔH = 66.78%) plays a crucial role in material dehydration and maturation in comparison with external heat. Meanwhile, the main water vapor output (Mvapor-out) accounted for 83.34% of the total water output, indicating that water evaporation assisted by high-efficiency ventilation is a leading way for water removal. Therefore, the B&M process via the linkage effects of auxiliary measures makes a prominent contribution that can greatly accelerate the composting course of FW into reusable organic fertilizer, as well as decrease the consumption of energy.