Enhanced Nitrate Nitrogen Removal from Constructed Wetland via Fe[sub.3]O[sub.4]/Granular Activated Carbon Anode Microbial Electrolysis Cell under Low C/N Ratio

• Published in: Water (Basel) Vol. 16; no. 10
• Main Authors: Yang, Heng, Tan, Shenyu, Huang, Yu, Tang, Xinhua
• Format: Journal Article
• Language: English
• Published: MDPI AG 01-05-2024
• Subjects: Ecosystems; Ethylenediaminetetraacetic acid; Tetracycline; Tetracyclines; Water, Underground; Wetlands; China
• ISSN: 2073-4441; 2073-4441
• DOI: 10.3390/w16101377

In this study, a constructed wetland–Fe[sub.3]O[sub.4]/granular activated carbon anode microbial electrolysis cell (CW-FMEC) was constructed to enhance denitrification in low COD/N ratio wastewater. The introduction of Fe[sub.3]O[sub.4] boosted the expression of functional genes involved in the denitrification pathway, and the abundance of narG, nirS, and nosZ increased by 99.29%, 70.54%, and 132.18%, respectively, compared to CW. In addition, the content of c-type cytochromes (c-Cyts) and EPS were also enhanced in the CW-FMEC. The microbial communities study displayed that Thauera, Dechloromonas, and Arenimonas became the main genera for denitrification. The denitrification performance at different COD/N ratios was investigated in depth. Under optimal working circumstances, the CW-FMEC had an excellent nitrate removal rate (88.9% ± 1.12%) while accumulating nearly no NO[sub.2] [sup.−]-N or NH[sub.4] [sup.+]-N in the effluent. This study provides a new direction for the development of CW-MEC and accelerates its implementation.