Thermally activated persulfate-driven rapid abiotic carbon source production of food waste: Performance, organic...

The efficient management of food waste (FW) has emerged as a pivotal bottleneck impeding the sustainable development of the urban circular economy. This work employs a thermally activated persulfate (PDS) system to investigate abiotic carbon source production pathways of FW, aiming to achieve efficient resource utilization through biorefinery. The physicochemical properties, structure-activity relationship, and carbon source products analysis of FW during the conversion process revealed that the introduction of PDS significantly enhanced the hydrolysis and the dissolution of organic matter. Under the optimal conditions of PDS dosage of 0.2 mmol/g VS, 70 °C, and 1 h, the system achieved the highest carbon source production efficiency, with SCOD and TOC reaching 13726.0 ± 325.6 mg/L and 3862.0 ± 95.2 mg/L, respectively, representing increases of 35.2% and 26.6% relative to the control. The resulting FW-derived carbon source exhibited significantly elevated concentrations of volatile fatty acids, reducing sugars, and soluble sugars, indicating that complex particulate organic matter was effectively transformed into highly bioavailable low-molecular-weight compounds. EPR analysis elucidated that the ∙OH and ∙SO₄^- were the key reactive species driving the cleavage, depolymerization, and solubilization of macromolecular organic matter. Simultaneously, dissolved organic matter evolved from protein-like and microbially derived components toward humic-like substances, revealing the synergistic parallel characteristic of carbon source production and humification. In the batch nitrate utilization tests, the FW-derived carbon source achieved a denitrification rate of 70.56 mg/(g MLVSS·d), indicating its feasibility as an alternative external carbon source. As a technology for rapid carbon source production of FW, this approach is anticipated to enhance the utilization efficiency of low-grade resources, while facilitating waste resource utilization and offering feasible and important support for circular economy and sustainable urban development.