Microelectrolysis-integrated constructed wetland with sponge iron filler to simultaneously enhance nitrogen and phosphorus removal

• Published in: Bioresource technology 2023-09, Vol.384, p.129270-129270, Article 129270
• Main Authors: Hou, Xiaoxiao, Chu, Linglong, Wang, Yifei, Song, Xinshan, Liu, Yingying, Li, Dongpeng, Zhao, Xiaoxiang
• Format: Article
• Language: English
• Subjects: Constructed wetland; Denitrification; Iron; Microelectrolysis; Nitrogen - analysis; Nitrogen removal; Phosphorus - analysis; Phosphorus removal; Sponge iron; Waste Disposal, Fluid - methods; Wetlands
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2023.129270

[Display omitted] •Integrating microelectrolysis into SICW alleviated dissolution and corrosion of SI.•The e-SICW decreased the accumulation of NH4+-N than SICW.•The e-SICW simultaneously enhanced nitrogen and phosphorus removal.•Hydrogenophaga was highly enriched in the e-SICW. Integrating sponge iron (SI) and microelectrolysis individually into constructed wetlands (CWs) to enhance nitrogen and phosphorus removal are challenged by ammonia (NH4+-N) accumulation and limited total phosphorus (TP) removal efficiency, respectively. In this study, a microelectrolysis-assisted CW using SI as filler surrounding the cathode (e-SICW) was successfully established. Results indicated that e-SICW reduced NH4+-N accumulation and intensified nitrate (NO3–-N), the total nitrogen (TN) and TP removal. The concentration of NH4+-N in the effluent from e-SICW was lower than that from SICW in the whole process with 39.2–53.2 % decrease, and as the influent NO3–-N concentration of 15 mg/L and COD/N ratio of 3, the removal efficiencies of NO3–-N, TN and TP in e-SICW achieved 95.7 ± 1.9 %, 79.8 ± 2.5 % and 98.0 ± 1.3 %, respectively. Microbial community analysis revealed that hydrogen autotrophic denitrifying bacteria of Hydrogenophaga was highly enriched in e-SICW.