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Wang W, Dong L, Zhai T, Wang W, Wu H, Kong F, Cui Y, Wang S. Bio-clogging mitigation in constructed wetland using microbial fuel cells with novel hybrid air-photocathode. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 881:163423. [PMID: 37062319 DOI: 10.1016/j.scitotenv.2023.163423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 04/05/2023] [Accepted: 04/06/2023] [Indexed: 06/01/2023]
Abstract
Excessive accumulation of extracellular polymeric substances (EPS) in constructed wetland (CW) substrate can lead to bio-clogging and affect the long-term stable operation of CW. In this study, a microbial fuel cell (MFC) was coupled with air-photocathode to mitigate CW bio-clogging by enhancing the micro-electric field environment. Because TiO2/biochar could catalyze and accelerate oxygen reduction reaction, further promoting the gain of electric energy, the electricity generation of the tandem CW-photocatalytic fuel cell (CW-PFC) reached 90.78 mW m-3. After bio-clogging was mitigated in situ in tandem CW-PFC, the porosity of CW could be restored to about 62.5 % of the initial porosity, and the zeta potential of EPS showed an obvious increase (-14.98 mV). The removal efficiencies of NH4+-N and chemical oxygen demand (COD) in tandem CW-PFC were respectively 31.8 ± 7.2 % and 86.1 ± 6.8 %, higher than those in control system (21.1 ± 11.0 % and 73.3 ± 5.6 %). Tandem CW-PFC could accelerate the degradation of EPS into small molecules (such as aromatic protein) by enhancing the electron transfer. Furthermore, microbiome structure analysis indicated that the enrichment of characteristic microorganisms (Anaerovorax) for degradation of protein-related pollutants, and electroactive bacteria (Geobacter and Trichococcus) promoted EPS degradation and electron transfer. The degradation of EPS might be attributed to the up-regulation of the abundances of carbohydrate and amino acid metabolism. This study provided a promising new strategy for synergic mitigation and prevention of bio-clogging in CW by coupling with MFC and photocatalysis.
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Affiliation(s)
- Wenyue Wang
- College of Environmental Science and Engineering, Qingdao University, Qingdao 266071, China; Carbon Neutrality and Eco-Environmental Technology Innovation Center of Qingdao, Qingdao 266071, China
| | - Liu Dong
- College of Environmental Science and Engineering, Qingdao University, Qingdao 266071, China; Carbon Neutrality and Eco-Environmental Technology Innovation Center of Qingdao, Qingdao 266071, China
| | - Tianyu Zhai
- College of Environmental Science and Engineering, Qingdao University, Qingdao 266071, China; Carbon Neutrality and Eco-Environmental Technology Innovation Center of Qingdao, Qingdao 266071, China
| | - Wenpeng Wang
- College of Environmental Science and Engineering, Qingdao University, Qingdao 266071, China; Carbon Neutrality and Eco-Environmental Technology Innovation Center of Qingdao, Qingdao 266071, China
| | - Huazhen Wu
- College of Environmental Science and Engineering, Qingdao University, Qingdao 266071, China; Carbon Neutrality and Eco-Environmental Technology Innovation Center of Qingdao, Qingdao 266071, China
| | - Fanlong Kong
- College of Environmental Science and Engineering, Qingdao University, Qingdao 266071, China; Carbon Neutrality and Eco-Environmental Technology Innovation Center of Qingdao, Qingdao 266071, China
| | - Yuqian Cui
- College of Environmental Science and Engineering, Qingdao University, Qingdao 266071, China; Carbon Neutrality and Eco-Environmental Technology Innovation Center of Qingdao, Qingdao 266071, China.
| | - Sen Wang
- College of Environmental Science and Engineering, Qingdao University, Qingdao 266071, China; Carbon Neutrality and Eco-Environmental Technology Innovation Center of Qingdao, Qingdao 266071, China.
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Wu T, Zhong L, Pang JW, Ren NQ, Ding J, Yang SS. Effect of Fe3+ on the nutrient removal performance and microbial community in a biofilm system. Front Microbiol 2023; 14:1140404. [PMID: 37089551 PMCID: PMC10117941 DOI: 10.3389/fmicb.2023.1140404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 03/22/2023] [Indexed: 04/08/2023] Open
Abstract
In this study, the influence of Fe3+ on N removal, microbial assembly, and species interactions in a biofilm system was determined. The results showed that maximum efficiencies of ammonia nitrogen (NH4+-N), total nitrogen (TN), phosphorus (P), and chemical oxygen demand (COD) removal were achieved using 10 mg/L Fe3+, reaching values of 100, 78.85, 100, and 95.8%, respectively, whereas at concentrations of 15 and 30 mg/L Fe3+ suppressed the removal of NH4+-N, TN, and COD. In terms of absolute abundance, the expression of bacterial amoA, narG, nirK, and napA was maximal in the presence of 10 mg/L Fe3+ (9.18 × 105, 8.58 × 108, 1.09 × 108, and 1.07 × 109 copies/g dry weight, respectively). Irrespective of Fe3+ concentrations, the P removal efficiency remained at almost 100%. Candidatus_Competibacter (10.26–23.32%) was identified as the most abundant bacterial genus within the system. Determinism (50%) and stochasticity (50%) contributed equally to microbial community assembly. Co-occurrence network analysis revealed that in the presence of Fe3+, 60.94% of OTUs in the biofilm system exhibited positive interactions, whereas 39.06% exhibited negative interactions. Within the OTU-based co-occurrence network, fourteen species were identified as key microbes. The stability of the system was found to be predominantly shaped by microbial cooperation, complemented by competition for resources or niche incompatibility. The results of this study suggested that during chemical P removal in wastewater treatment plants using biofilm methods, the concentration of supplemental Fe3+ should be maintained at 10 mg/L, which would not only contribute to P elimination, but also enhance N and COD removal.
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Affiliation(s)
- Tong Wu
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, China
| | - Le Zhong
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, China
| | - Ji-Wei Pang
- China Energy Conservation and Environmental Protection Group, CECEP Talroad Technology Co., Ltd., Beijing, China
| | - Nan-Qi Ren
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, China
| | - Jie Ding
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, China
- *Correspondence: Jie Ding,
| | - Shan-Shan Yang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, China
- Shan-Shan Yang,
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