J* E* C* N* U* N* S* ›› 2026, Vol. 2026 ›› Issue (1): 66-77.doi: 10.3969/j.issn.1000-5641.2026.01.006

• Innovation in Watershed Ecological Restoration Technologies • Previous Articles     Next Articles

Research progress on the application of constructed wetlands with iron-rich substrates for low C/N ratio wastewater treatment

Jing WANG1,2,3,4, Yan HE1,2,3,4,*()   

  1. 1. School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
    2. Institute of Eco-Chongming, Shanghai 202151, China
    3. Shanxi Key Laboratory of Water Pollution Prevention and Utilization, Taiyuan 030009, China
    4. Technology Innovation Center for Land Spatial Eco-Restoration in Metropolitan Area (Ministry of Natural Resources), Shanghai 200062, China
  • Received:2025-09-08 Accepted:2025-12-15 Online:2026-01-25 Published:2026-01-29
  • Contact: Yan HE E-mail:yhe@des.ecnu.edu.cn

Abstract:

Constructed wetlands (CWs) are commonly used as the final treatment stage before discharging effluents from wastewater treatment plants (WWTPs) into natural waters. However, effectively treating carbon-limited but nutrient-enriched effluents remains challenging. Iron-rich substrates offer a promising solution because of their high adsorption capacities, redox activity, and biological affinity. In this study, we review the research directions and hotspots related to the application of iron-rich substrates in CWs, with an emphasis on their performance under low C/N ratio wastewater conditions. We also elucidate the synergistic mechanisms by which iron-rich substrates (i) stimulate microbial coupling of iron and nitrogen cycles for nitrogen removal and (ii) integrate surface adsorption, precipitation, ligand exchange, and co-precipitation for phosphorus removal. Considering the potential issues that may arise during the long-term operation of iron-rich CWs, such as iron passivation, clogging, microbial iron toxicity, and accumulation of denitrification byproducts, this study proposes recommendations for future research in terms of material development, system optimization, and mechanism exploration. These suggestions aim to provide strong support for improving purification efficiency and ensuring the long-term stable operation of CWs treating effluents from WWTPs.

Key words: iron-rich substrate, constructed wetland for effluent treatment, iron cycle, iron plaque

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