Synchronous and efficient removal of carbon, nitrogen, and phosphorus from actual rural sewage by composite wetlands enhanced with functional fillers

• Published in: Bioresource technology Vol. 414; p. 131566
• Main Authors: Guo, Bing-Xu, Shi, Wei-Yi, Ai, Jun-Yu, Zhang, Ke-Jia, Wang, Qiu-Gang, Wang, Wen-Huai, Li, Jun-Feng
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.12.2024
• Subjects: Activated sludge; Constructed wetland; Coupling reinforcement; Efficient phosphorus adsorbent; Wastewater treatment; Activated sludge; Coupling reinforcement; Wastewater treatment; Efficient phosphorus adsorbent; Constructed wetland
• ISSN: 0960-8524; 1873-2976; 1873-2976
• DOI: 10.1016/j.biortech.2024.131566

[Display omitted] •Filler composition rich in Al3+and Ca2+ guaranteed its chemisorption of PO43−.•Calcination increased the pore volume of filler thereby promoting its physisorption.•Nutrient and oxygen partitioning in wetland formed different microbial community.•Composite wetland purification coupled physical, chemical, and biological processes.•Actual sewage met the Class 1A standard after being treated by composite wetland. A composite wetland (CECW) was constructed by introducing P-adsorption filler (EPAF) and activated sludge into traditional wetlands for treating actual sewage. The results showed that EPAF improved P removal through physico-chemical adsorption, and it could be stably regenerated after adsorption saturation without potential risks. Meanwhile, zeolite promoted NH4+-N reduction in sewage by cation exchange. In addition, simultaneous biological removal of carbon, nitrogen, and phosphorus was achieved through nitrification, denitrification, anammox, and aerobic P-accumulation processes induced by Nitrobacter, Proteus Hauser, Candidatus Paracaedibacter, and Brevundimonas. Under the coupling of filler interception/adsorption, microbial assimilation/transformation, flocculation, and plant uptake, CECW obtained the removal rates of 93.22 %, 85.75 %, 91.80 %, 95.38 %, 97.07 %, and 78.05 % for turbidity, TN, NH4+-N, TP, PO43−-P, and TCOD, which met the Class 1A standard (GB18918-2002). Therefore, the experiment systematically investigated the effects and mechanism of CECW in treating actual sewage, which could provide reference for rural sewage treatment and sludge utilization.