Selective O3/SPC oxidation minimizes the carbon footprint of concentrated aromatic remediation via in situ endogenous carbon.

Managing recalcitrant aromatic pollutants with high toxicity and low biodegradability in industrial wastewater has been a persistent global challenge. Conventional pretreatment of aromatic pollutants with hydroxyl radicals (•OH) non-selectively destroys the intrinsic carbon essential for subsequent biological treatment, thus necessitating costly exogenous carbon supplementation accompanied by prominent CO2 emissions. Herein, we introduce an ozone/percarbonate (O3/SPC) system engineered to deliver electrophilic carbonate radicals (CO3•-) that target the electron-rich conjugated π-systems of aromatic pollutants, promoting ring fragmentation and efficiently converting primary aromatic carbon into valuable endogenous feedstocks, primarily biodegradable acetate and formate. When applied to actual pesticide wastewater dominated by xylene (initial COD = 11000 mg L-1), this O3/SPC strategy boosts the BOD5/COD ratio from an initial 0.01 to 0.45, two times higher than that (0.22) achieved in the •OH-dominated O3/H2O2 counterpart system, thereby enabling self-sufficient downstream anaerobic digestion (AD) followed by anaerobic/aerobic (A/O) treatment to reduce the chemical oxygen demand below 50 mg L-1 and total nitrogen (TN) below 15 mg L-1. Further life cycle analyses demonstrate the O3/SPC process reduces carbon emissions by 40.2% relative to the O3/H2O2 counterpart, establishing a low-carbon, resource-efficient approach for remediating bio-refractory industrial effluents.