Microwave-alkali co-activated persulfate enables minute-scale fertilization of food waste with high fulvic-like acid yield

<title>Abstract</title> This study demonstrated rapid humification of waste potato (WP), as a model food waste, into fulvic-like acid (FLA) fertilizer (15wt% FLA and 7.6wt% K ⁺ ) using microwave-triggered KOH/persulfate (MW/KOH/PS) process. Under synergistic MW irradiation (180 W) and KOH (2wt%), PS (2wt%) was activated to generate •OH and •SO ₄ ^- . This process simultaneously dissolved organic matter and elevated system temperature, inducing humification of organic components within 10 minutes. Compositional analyses revealed Maillard reactions and amidation during humification. Compared to KOH/PS, microwave intensification reduced chemical consumption by 75%, while achieving comparable FLA yields and significantly lowering cost by 62.4%. Pot experiments validated the plant-growth promotion and soil-amendment capabilities of the humified product. Scale-up trials confirmed the efficacy for practical vegetable residues and cooked food waste. Unlike composting (20-60 d), this process completed in 10 min without requiring optimal C/N ratio or moisture content, exhibited only 20.1% carbon loss (WP system), and operated in scalable reactor, thus enabling same-day waste valorization into fertilizer.