Mejora de la biodisponibilidad de lodos activados de residuos lisados alcalinamente mediante el uso de acetato de...

Alkaline lysis (AL) for waste activated sludge (WAS) resource utilization is often hindered by refractory organic matter formation. This study developed NaAc-coupled AL-WAS (NaAc-AL-WAS) technology to improve bioavailability. Compared to AL-WAS, the five-day biochemical oxygen demand and soluble chemical oxygen demand ratios of 0.5%, 1%, and 5% NaAc-AL-WAS increased by 0.9-, 1.1-, and 1.3-fold. Specifically, 5% NaAc-AL-WAS reduced humic substances (HS) and high-molecular-weight proteins by 10.3% and 61.0%. The denitrification rate and potential increased by 5.1- and 0.4-fold, while methanogenic rate and maximum methane potential increased by 3.4- and 1.2-fold. Mechanistically, NaAc maintained strongly alkaline environment and promoted flocculation for continuous organic release. NaAc-induced iron precipitation (Fe²⁺/Fe³⁺ below the detection line in the lysate) and Fe(Ⅲ) reduction (24.5% decrease in the sludge) weakened iron binding and catalytic activity toward humic precursors, inhibiting HS formation to enhance bioavailability. These findings provided a new approach to optimize carbon resource recovery from sludge.