Synergistic removal of various emergent pollutants in biochar-enhanced constructed wetlands: a pilot-scale nature-based solution for municipal wastewater treatment improvements

Article Article scientifique Article Synergistic removal of various emergent pollutants in biochar-enhanced constructed wetlands: a pilot-scale nature-based solution for municipal wastewater treatment improvements eng 2026-03-11 author Maldou Chaimae author EL Janoussi Yasmina 440402 author Al Salah Dhafer Mohammed M. 892817 author Lahrouni Majida author Ouazzani Naaila author Kurnaiwan Tonni Agustiono author El Ghadraoui Ayoub author Elleuch Amine author Ammar Aroua author Pote-Wembonyama John 0000-0003-4091-749X 525637 Forel Communs (FOREL) author Aziz Faissal 1762724 10.3389/fenvc.2026.1762724 2673-4486 https://www.frontiersin.org/articles/10.3389/fenvc.2026.1762724/full The primary drawback of reusing treated wastewater for irrigation is that most wastewater treatment plants (WWTPs) remain unable to remove most emerging pollutants detected in recent decades, necessitating a strategy to improve these WWTPs’ performance. In this regard, the present study aims to evaluate the effectiveness of an enhanced pilot vertical-flow biochar-enriched constructed wetland for treating municipal wastewater pretreated with natural lagoons. Three key harmful micropollutants are addressed: heavy metals (trace elements), pharmaceutical residues, and antibiotic-resistant bacteria (ARB). The system utilizes a biochar layer to enhance treatment efficiency by increasing adsorption capacity and supporting beneficial microorganisms, in conjunction with Phragmites australis plants that facilitate oxygen transfer and nutrient uptake. To evaluate the treatment system’s performance, Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used to measure heavy metal concentrations. A molecular approach using quantitative polymerase chain reaction (qPCR) was used to quantify antibiotic resistance genes (ARGs) in water samples before and after treatment, including β-lactamases TEM, CTX-M, and SHV. The performance obtained is remarkable for the well-known toxic metals, reducing their concentrations from 16.35 ± 0.82 μg L -1 for arsenic, 0.0936 ± 0.0047 μg L -1 for cadmium, and 0.6036 ± 0.030 μg L -1 for lead to 2.75 ± 0.14 μg L -1 , 0.0014 ± 0.000070 μg L -1 , and 0.089 ± 0.0045 μg L -1 , respectively. Furthermore, the results showed a significantly reduced copy number of the 16S rRNA gene and of the resistance-conferring genes. Pharmaceutical residues (doxycycline, ciprofloxacin, enoxacin, enrofloxacin, norfloxacin, ofloxacin, amoxicillin and ampicillin) were also effectively removed after treatment, with removal rates ranging from 63% to over 99% depending on the compound. For example, ibuprofen and ciprofloxacin were reduced by 96%–97% (from 7.310 to 238 ng L -1 and from 2.300 to 83 ng L -1 , respectively). Even recalcitrant molecules such as carbamazepine and diclofenac have been reduced by more than 60%, confirming the high efficiency of the biochar-enriched artificial wetland system. These results highlight the considerable potential of this nature-based solution as a promising approach to addressing the global concern of enhancing WWTP removal of emergent pollutants. It therefore offers a sustainable, environmentally friendly alternative for wastewater treatment reuse in irrigation. Dewey 550 Dewey 333.7-333.9 18 Institut des sciences de l'environnement 0DB 41 Département F.-A. Forel des sciences de l'environnement et de l'eau 153 false 1217 FORE9 Environmental microbiology Frontiers in environmental chemistry 7 ff9683f6-0c7f-409f-8569-dac2e1669e09 Article (Published version) Public Article_scientifique_from_unpaywall.pdf 4693439 application/pdf CC BY d1425a0a3db41fbd99cc590fccba7a148243679f8e161e92702b1f96ae777244 openAccess Centres et instituts / Institut des sciences de l'environnement Faculté des sciences / Section des sciences de la Terre et de l'Environnement / Département F.-A. Forel des sciences de l'environnement et de l'eau

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Synergistic removal of various emergent pollutants in biochar-enhanced constructed wetlands: a pilot-scale nature-based solution for municipal wastewater treatment improvements	Frontiers in environmental chemistry			2026	8	6

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EL Janoussi, Yasmina