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De Sotto R, Bae S. Nutrient removal performance and microbiome of an energy-efficient reciprocation MLE-MBR operated under hypoxic conditions. WATER RESEARCH 2020; 182:115991. [PMID: 32739686 DOI: 10.1016/j.watres.2020.115991] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 05/06/2020] [Accepted: 05/27/2020] [Indexed: 06/11/2023]
Abstract
A critical challenge in the application of membrane bioreactors (MBR) for domestic wastewater treatment is its high energy consumption caused by continuous aeration for biofouling control. To reduce energy consumption and mitigate fouling in membranes, alternative configurations using dynamic shear-enhanced filtration by membrane reciprocation, rotation, and vibration to mechanically impose shear on membrane surfaces have been recently introduced. However, although these methods are effective at lowering energy usage, the nutrient removal efficiencies and microbial community compositions of these systems have not been well studied. In this study, a lab-scale no-aeration reciprocation membrane bioreactor was used to characterize the microbial composition, functional profile and nutrient removal of the reciprocation MBR system operated under hypoxic conditions. Microbial community analysis showed Proteobacteria (35%) and Saccharibacteria (27%) to be the most abundant phyla in the sludge and the biofilm samples, respectively. Nitrogen and phosphorus removal efficiencies were observed at 70% and 50% while the chemical oxygen demand concentration had about a 99% decrease in the effluent. Quantitative PCR of nutrient-removing genes revealed the presence of complete ammonia-oxidizing organisms (comammox) with a mean abundance of 1.88 × 104 gene copies/g sludge, which explains the high ammonia removal despite a low abundance of canonical ammonia-oxidizing bacteria (AOB). Fluorescence in-situ hybridization showed a prevalence of nitrite-oxidizing bacteria (NOB) with clusters that are distant from other nutrient-removing communities, suggesting that their metabolism is not dependent on ammonia oxidizers. The reciprocation MBR configuration may be a suitable, more energy-efficient alternative to conventional air-scouring systems because of its biofouling mitigation and promising nutrient removal performed by the diverse microbial communities in its system.
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Affiliation(s)
- Ryan De Sotto
- Civil and Environmental Engineering Department, National University of Singapore, 1 Engineering Drive 2, #07-03 E1A, 117576, Singapore
| | - Sungwoo Bae
- Civil and Environmental Engineering Department, National University of Singapore, 1 Engineering Drive 2, #07-03 E1A, 117576, Singapore.
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Wu Y, Cai Y, Lu YX, Zhang LM, Yang XL, Song HL, Yang YL. Bioelectrochemically-assisted nitrogen removal in osmotic membrane bioreactor. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2020; 82:330-338. [PMID: 32941174 DOI: 10.2166/wst.2020.184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Nitrogen removal in osmosis membrane bioreactor (OMBR) is important to its applications but remains a challenge. In this study, a bioelectrochemically-assisted (BEA) operation was integrated into the feed side of OMBRs to enhance nitrogen removal, and sodium acetate was served as a draw solute and supplementary carbon source for the growth of denitrifying bacteria due to reversed-solute. The effects of operation mode and influent ammonium (NH4 +) concentration were systematically examined. Compared to a conventional OMBR, the integrated BEA-OMBR achieved higher total nitrogen removal efficiency of 98.13%, and chemical oxygen demand removal efficiency of 95.83% with the influent NH4 +-N concentration of 39 mg L-1. The sequencing analyses revealed that ammonia-oxidizing bacteria (0-0.04%), nitrite-oxidizing bacteria (0-0.16%), and denitrifying bacteria (1.98-8.65%) were in abundance of the microbial community in the feed/anode side of integrated BEA-OMBR, and thus BEA operation increased the diversity of the microbial community in OMBR. Future research will focus on improving nitrogen removal from a high ammonium strength wastewater by looping anolyte effluent to the cathode. These findings have demonstrated that BEA operation can be an effective approach to improve nitrogen removal in OMBRs toward sustainable wastewater treatment.
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Affiliation(s)
- You Wu
- School of Environment, Nanjing Normal University, Jiangsu Engineering Lab of Water and Soil Eco-remediation, Wenyuan Road 1, Nanjing 210023, China E-mail:
| | - Yun Cai
- School of Environment, Nanjing Normal University, Jiangsu Engineering Lab of Water and Soil Eco-remediation, Wenyuan Road 1, Nanjing 210023, China E-mail:
| | - Yu-Xiang Lu
- School of Environment, Nanjing Normal University, Jiangsu Engineering Lab of Water and Soil Eco-remediation, Wenyuan Road 1, Nanjing 210023, China E-mail:
| | - Li-Min Zhang
- School of Environment, Nanjing Normal University, Jiangsu Engineering Lab of Water and Soil Eco-remediation, Wenyuan Road 1, Nanjing 210023, China E-mail: ; Green Economy Development Institute, Nanjing University of Finance and Economics, Nanjing 210023, China
| | - Xiao-Li Yang
- School of Civil Engineering, Southeast University, Nanjing 210096, China
| | - Hai-Liang Song
- School of Environment, Nanjing Normal University, Jiangsu Engineering Lab of Water and Soil Eco-remediation, Wenyuan Road 1, Nanjing 210023, China E-mail:
| | - Yu-Li Yang
- School of Environment, Nanjing Normal University, Jiangsu Engineering Lab of Water and Soil Eco-remediation, Wenyuan Road 1, Nanjing 210023, China E-mail:
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Teng J, Shen L, Xu Y, Chen Y, Wu XL, He Y, Chen J, Lin H. Effects of molecular weight distribution of soluble microbial products (SMPs) on membrane fouling in a membrane bioreactor (MBR): Novel mechanistic insights. CHEMOSPHERE 2020; 248:126013. [PMID: 32004890 DOI: 10.1016/j.chemosphere.2020.126013] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 01/12/2020] [Accepted: 01/22/2020] [Indexed: 06/10/2023]
Abstract
While molecular weight distribution (MWD) is one of the most important properties of soluble microbial products (SMPs), mechanisms underlying effects of MWD of SMPs on membrane fouling have not well unveiled. In this study, it was found that, the supernatant of sludge suspension in a membrane bioreactor (MBR) for wastewater treatment can be fractionated into a series of SMPs samples with different molecular weight (MW) fraction. The real gel sample mainly formed by the rejected SMPs on membrane surface had a high specific filtration resistance (SFR) of 1.21 × 1016 m-1 kg-1. The SFR of SMPs samples and the model foulants of polyethylene glycol (PEG) increased with their MW. The change trend of SFR with MW cannot be sufficiently explained by three-dimensional excitation-emission matrix (EMM) and chemical compositions. Tyndall effect analysis indicated that gelating ability of SMPs and PEG in the solution increased with their MW. Scanning electron microscope (SEM) confirmed gel structure changes with the PEG MW. Accordingly, mechanisms based on Carman-Kozeny equation and Flory-Huggins lattice theory were proposed to interpret SFR of SMPs with low and high MW, respectively. Simulating these two mechanistic models on PEG samples resulted in the comparable SFR data to the experimental ones, indicating the correctness and feasibility of the proposed mechanisms. The proposed mechanisms provided in-depth understanding of membrane fouling regarding MW, facilitating to develop effective membrane fouling mitigation strategies.
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Affiliation(s)
- Jiaheng Teng
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, China
| | - Liguo Shen
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, China
| | - Yanchao Xu
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, China
| | - Yifeng Chen
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, China
| | - Xi-Lin Wu
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, China
| | - Yiming He
- Department of Materials Science and Engineering, Zhejiang Normal University, Jinhua, 321004, China
| | - Jianrong Chen
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, China.
| | - Hongjun Lin
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, China.
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