Enhancement of low C/N wastewater treatment and plant growth in sulfur-based constructed wetlands through arbuscular mycorrhizal fungi inoculation

• Published in: Journal of water process engineering 2025-01, Vol.69, p.106799, Article 106799
• Main Authors: Wang, Hanyue, Zhu, Fengxiang, Liu, Qinxue, You, Lexing, Hu, Shanshan, Hu, Bo, Wang, Qi, Chen, Zhongbing
• Format: Article
• Language: English
• Subjects: Constructed wetlands; Mycorrhizal symbiosis; Nitrogen removal; Sulfur autotrophic denitrification
• ISSN: 2214-7144; 2214-7144
• DOI: 10.1016/j.jwpe.2024.106799

Sulfur (S)-based constructed wetlands (CWs) are effective in removing pollutants from low carbon to nitrogen (C/N) wastewater, though nitrogen removal efficiency is limited. Additionally, by-products of sulfur may adversely affect plant growth. This study investigated the effects of arbuscular mycorrhizal fungi (AMF) inoculation on wastewater treatment across different C/N ratios (1, 5, 10) alongside evaluating the growth of Iris pseudacorus in S-based CWs. Results showed that AMF colonization in I. pseudacorus increased with rising C/N ratios in S-based CWs. AMF and sulfur jointly enhanced pollutant removal efficiencies, particularly at C/N ratios of 1 and 5. The NO3−-N, COD, and TP removal efficiencies were improved by 19.9–34.1 %, 1.8–8.0 %, and 1.3–6.6 %, respectively, in AMF-inoculated S-based CWs (ASCW) compared to controls. Although NH4+-N removal was reduced in S-based CWs, AMF inoculation boosted NH4+-N removal by 3.5–20.7 %. Additionally, AMF inoculation enhanced the antioxidant response and photosynthesis in I. pseudacorus within S-based CWs, increasing SOD, POD, and CAT activities increased by 6.9–16.5 %, 0.7–10.7 %, and 1.1–3.9 %, respectively, while reducing MDA concentrations by 14.5–22.0 %. Mantel test analysis revealed a positive correlation between plant growth and wastewater purification under low C/N conditions. This study highlights AMF's significant role in improving low C/N wastewater treatment and promoting wetland plant growth in S-based CWs. [Display omitted] •Arbuscular mycorrhizal fungi (AMF) enhanced low C/N wastewater purification in sulfur (S)-based constructed wetlands (CWs)•The greatest effect of S and AMF on nitrogen removal determined at the C/N ratios of 1 and 5•AMF and S addition in CWs promoted the antioxidant response and photosynthesis performance of I. pseudacorus•Mantel test correlation analysis revealed a positive correlation between plant growth and low C/N wastewater purification