TANDEM "HETEROGENEOUS CATALYSIS/BIOLOGICAL DEGRADATION" OPTIMIZATION FOR THE TREATMENT OF RECALCITRANT COMPOUNDS IN INDUSTRIAL STREAMS  

COVINICH L.G.; MASSA P.; FERRO OROZCO, A.M.; FELISSIA F.E.; AREA M.C.

Journal of Water Process Engineering

Elsevier

Año: 2025

2214-7144

This study aims to develop a combined Advanced Oxidation Process (AOP)/biological system. The goal is to identify conditions that enable the recalcitrant organic load of a real alkaline sulfite industrial effluent maximum reduction, minimizing the leaching of the active phase from the catalytic support and reusing the catalyst in successive reactions. This study presents a combined heterogeneous catalysis/biological treatment approach for treating real industrial wastewater (black liquor from the alkaline sulfite treatment of forest biomass). A Fenton-type oxidation process using a 2.5% CuO/γ-Al2O3 catalyst was optimized, achieving significant reductions in Total Organic Carbon (TOC), Chemical Oxygen Demand (COD), Aromaticity, and leaching of Cu2+. Inorganic components in the liquor were identified as hindering factors, while the organic fraction proved highly recalcitrant. The catalyst can maintain its effectiveness for up to five consecutive cycles. The optimized Fenton pre-treatment enhanced biodegradability, increasing the Biological Oxygen Demand/COD ratio to 0.23, and exhibited minimal toxicity to the microbial community. Subsequent biological treatment was carried out using activated sludge cultured in an aerobic laboratory-scale reactor with partial biomass recycling. The combined AOP/ biological system achieved a global 86% TOC reduction and 93% COD reduction. With the combination of processes, the current Argentine regulations regarding COD levels in industrial discharges are complied with, adhering to the maximum allowed limit of 250 mg/L in most provinces. Copper leaching from the catalyst was observed. However, the leached copper retained its catalytic activity, probably due to complexation with organic intermediates.