Radical-Induced Abiotic Humification of Food Waste and Wood Ash into Fulvic-Like Fertilizer within 1 Hour

The enhancement of humification in food waste (FW) is critical for ecological conservation and resource recycling. However, as a common humification method, traditional composting had the disadvantages of a long cycle (at least 20 days) and cumbersome condition control (ventilation/temperature control to accelerate the reaction process), which highlighted the urgency of developing efficient utilization technologies. This work developed a novel hour-scale technology using KOH-activated persulfate (KOH/PS) with wood ash (WA) for moisture adjustment to rapidly convert FW to FLA-enriched fertilizer. Results showed that reactive oxidative species, including 1O2, HO•, SO4•–, and O2•–, were generated in the system, playing key roles in degradation and polymerization of FW/WA. The humification was completed within 45 min, producing fertilizer with 16 wt % FLA content. At the same time, the added PS and KOH were transformed into K2SO4 fertilizer, realizing full recycling. Pot experiments demonstrated significant yield increases of 288%, 119%, 163%, 131%, and 68% compared to Blank, FW, WA, FW/WA, and K2SO4 control groups, respectively, with good biosafety. This study provided a rapid and low cost artificial humification approach for FW, showing a huge application prospect.