A new approach of simultaneous adsorption and regeneration of activated carbon to address the bottlenecks of pharmaceutical wastewater treatment

• Published in: Water research (Oxford) 2024-03, Vol.252, p.121180-121180, Article 121180
• Main Authors: Qin, Weichen, Dong, Yuling, Jiang, Huan, Loh, Wei Hao, Imbrogno, Joseph, Swenson, Tim M., Garcia-Rodriguez, Orlando, Lefebvre, Olivier
• Format: Article
• Language: English
• Subjects: Electroadsorption; Electrochemical oxidation; In-situ sintered activated carbon regeneration; Real pharmaceutical wastewater treatment; Sustainable wastewater management; Versatile wastewater treatment
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2024.121180

•A concentrated real pharmaceutical wastewater was treated successfully with TOC removal at 87 %.•The system requires no chemical inputs other than catalytic amount of iron.•The system remained stable through 10 treatment cycles.•The regeneration of activated carbon was confirmed using various characterization methods. This study proposes a sustainable approach for hard-to-treat wastewater using sintered activated carbon (SAC) both as an adsorption filter and as an electrode, allowing its simultaneous electrochemical regeneration. SAC improves the activated carbon (AC) particle contact and thus the conductivity, while maintaining optimal liquid flow. The process removed 87 % of total organic carbon (TOC) from real high-load (initial TOC of 1625 mg/L) pharmaceutical wastewater (PWW), generated during the manufacturing of azithromycin, in 5 h, without external input of chemicals other than catalytic amounts of Fe(II). Kinetic modelling indicated that adsorption was the dominant process, while concomitant electrochemical degradation of complex organics first converted them to short-chain acids, followed by their full mineralization. In-situ electrochemical regeneration of SAC, taking place at the same time as the treatment, is a key feature of our process, enhancing its performance and ensuring its stable operation over time, while eliminating cleaning downtimes altogether. The energy consumption of this innovative process was remarkably low at 8.0×10−3 kWh gTOC−1. This study highlights the potential of SAC for treating hard-to-treat effluents by concurrent adsorption and mineralization of organics. [Display omitted]