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Homyok P, Rongsayamanont C, Wongkiew S, Limpiyakorn T. Sludge floc characteristics and microbial community in high-rate activated sludge and high-rate membrane bioreactor for organic recovery. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167387. [PMID: 37777134 DOI: 10.1016/j.scitotenv.2023.167387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 09/24/2023] [Accepted: 09/24/2023] [Indexed: 10/02/2023]
Abstract
High-rate activated sludge (HRAS) and high-rate membrane bioreactor (HRMBR) are considered as potential processes for organic recovery through bioflocculation and biosorption of particulate COD and colloidal COD with sludge flocs. In this study, bioflocculation and biosorption, in terms of sludge floc characteristics and microbial community, in HRAS and HRMBR was investigated in relation to organic recovery performance for low strength wastewater treatment. HRAS and HRMBR were operated at two different solids retention times (SRTs) of 2 and 0.8 days. Reducing the SRT of HRAS from 2.0 to 0.8 days resulted in failure in total COD (tCOD) removal efficiency (from 79 ± 2 to 34 ± 13 %) and lowering organic recovery (from 40.8 to 15.7 %). This contrasted with HRMBR, which showed high tCOD removal efficiency (84 ± 2 and 84 ± 1 %) and organic recovery (43.4 and 46.3 %) at both SRTs of 2.0 and 0.8 days. Analysis of sludge floc characteristics showed that the lower organic recovery of the HRAS operated at an SRT of 0.8 days could be associated with poor bioflocculation and biosorption, as evidenced by relatively larger floc size, higher extracellular polymeric substance, higher protein/polysaccharide ratio, and higher zeta potential value of the sludge. These characteristics were in contrast to the HRMBR operated at an SRT of 0.8 days, that exhibited the highest organic recovery among the reactors studied. The microbial taxa Bdellovibrio, Clostridium sensu stricto 9, Hyphomicrobium, and Ideonella could play a role in the poor bioflocculation and biosorption in HRAS. Rhodanobacter, Enterobacter, Terrimonas, Nakamurella, and Mizugakiibacter may be associated with bioflocculation and biosorption and organic recovery in HRMBR. The results of this study enhanced our understanding on the relationships between the microbial community, sludge floc characteristics, and organic recovery performance of HRAS and HRMBR for future optimization of the systems.
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Affiliation(s)
- Pratamaporn Homyok
- Department of Environmental Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand
| | - Chaiwat Rongsayamanont
- Faculty of Environmental Management, Prince of Songkla University, Songkhla 90110, Thailand
| | - Sumeth Wongkiew
- Department of Environmental Science, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand; Waste Utilization and Ecological Risk Assessment Research Unit, Chulalongkorn University, Bangkok 10330, Thailand
| | - Tawan Limpiyakorn
- Department of Environmental Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand; Biotechnology for Wastewater Engineering Research Unit, Chulalongkorn University, Bangkok 10330, Thailand.
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2
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Wu SL, Wei W, Ngo HH, Guo W, Wang C, Wang Y, Ni BJ. In-situ production of lactate driving the biotransformation of waste activated sludge to medium-chain fatty acid. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 345:118524. [PMID: 37423191 DOI: 10.1016/j.jenvman.2023.118524] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 06/14/2023] [Accepted: 06/25/2023] [Indexed: 07/11/2023]
Abstract
Medium-chain fatty acids (MCFAs) have drawn great attention due to their high energy density and superior hydrophobicity. Waste activated sludge (WAS) has been documented as a renewable feedstock for MCFAs production via anaerobic fermentation. However, MCFAs production from WAS depends on exogenous addition of electron donor (ED, e.g., lactate) for chain elongation (CE) bioprocess, which results in increased economic cost and limited practical application. In this study, a novel biotechnology was proposed to produce MCFAs from WAS with in-situ self-formed lactate by inoculating Yoghurt starter powder containing with Lactobacillales cultures. The batch experimental results revealed that the lactate was in-situ generated from WAS and the maximum production of MCFAs increased from 1.17 to 3.99 g COD/L with the increased addition of Lactobacillales cultures from 6✕107 to 2.3✕108 CFU/mL WAS. In continuous long-term test over 97 days, average MCFA production reached up to 3.94 g COD/L with a caproate yield of 82.74% at sludge retention time (SRT) 12 days, and the average MCFA production increased to 5.87 g COD/L with 69.28% caproate and 25.18% caprylate at SRT 15 days. A comprehensive analysis of the metagenome and metatranscriptome demonstrated that the genus of Lactobacillus and Streptococcus were capable of producing lactate from WAS and upgrading to MCFAs. Moreover, another genus, i.e., Candidatus Promineofilum, was firstly revealed that it might be responsible for lactate and MCFAs production. Further investigation of related microbial pathways and enzyme expression suggested that D-lactate dehydrogenase and pyruvate ferredoxin oxidoreductase contributed to lactate and acetyl-CoA production, which were the crucial steps for MCFAs generation and were most actively expressed. This study provides a conceptual framework of MCFAs from WAS with endogenous ED, potentially enhancing the energy recovery from WAS treatment.
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Affiliation(s)
- Shu-Lin Wu
- Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Zhejiang Engineering Research Center of Non-ferrous Metal Waste Recycling, Zhejiang Gongshang University, PR China
| | - Wei Wei
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW, 2007, Australia.
| | - Huu Hao Ngo
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Wenshan Guo
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Chen Wang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, PR China
| | - Yun Wang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, PR China
| | - Bing-Jie Ni
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW, 2007, Australia.
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Zhou S, Yang Z, Zhang S, Gao Y, Tang Z, Duan Y, Zhang Y, Wang Y. Metagenomic insights into the distribution, mobility, and hosts of extracellular antibiotic resistance genes in activated sludge under starvation stress. WATER RESEARCH 2023; 236:119953. [PMID: 37060877 DOI: 10.1016/j.watres.2023.119953] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 04/06/2023] [Accepted: 04/07/2023] [Indexed: 06/19/2023]
Abstract
Extracellular antibiotic resistance genes (eARGs) are important emerging environmental pollutants in wastewater treatment plants (WWTPs). Nutritional substrate deficiency (i.e., starvation) frequently occurs in WWTPs owing to annual maintenance, water quality fluctuation, and sludge storage; and it can greatly alter the antibiotic resistance and extracellular DNA content of bacteria. However, the fate and corresponding transmission risk of eARGs in activated sludge under starvation stress remain largely unknown. Herein, we used metagenomic sequencing to explore the effects of starvation scenarios (carbon, nitrogen, and/or phosphorus deficiency) and environmental conditions (alternating anaerobic-aerobic, anaerobic, anoxic, and aerobic) on the distribution, mobility, and hosts of eARGs in activated sludge. The results showed that 30 days of starvation reduced the absolute abundances of eARGs by 40.9%-88.2%, but high-risk dual and multidrug resistance genes persisted. Starvation, particularly the simultaneous lack of carbon, nitrogen, and phosphorus under aerobic conditions, effectively alleviated eARGs by reducing the abundance of extracellular mobile genetic elements (eMGEs). Starvation also altered the profile of bacterial hosts of eARGs and the bacterial community composition, the latter of which had an indirect positive effect on eARGs via changing eMGEs. Our findings shed light on the response patterns and mechanisms of eARGs in activated sludge under starvation conditions and highlight starvation as a potential strategy to mitigate the risk of previously neglected eARGs in WWTPs.
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Affiliation(s)
- Shuai Zhou
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai 200092, China; Hunan Province Key Laboratory of Pollution Control and Resources Reuse Technology, School of Civil Engineering, University of South China, Hengyang 421001, China
| | - Zhengqing Yang
- Hunan Province Key Laboratory of Pollution Control and Resources Reuse Technology, School of Civil Engineering, University of South China, Hengyang 421001, China
| | - Siqi Zhang
- Hunan Province Key Laboratory of Pollution Control and Resources Reuse Technology, School of Civil Engineering, University of South China, Hengyang 421001, China
| | - Yuanyuan Gao
- Hunan Province Key Laboratory of Rare Metal Minerals Exploitation and Geological Disposal of Wastes, University of South China, Hengyang 421001, China
| | - Zhenping Tang
- Hunan Province Key Laboratory of Rare Metal Minerals Exploitation and Geological Disposal of Wastes, University of South China, Hengyang 421001, China
| | - Yi Duan
- Hunan Province Key Laboratory of Pollution Control and Resources Reuse Technology, School of Civil Engineering, University of South China, Hengyang 421001, China
| | - Yalei Zhang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai 200092, China
| | - Yayi Wang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai 200092, China.
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4
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Miwa T, Takimoto Y, Mizuta Y, Hatamoto M, Watari T, Yamaguchi T. An increase in sludge loading rate induces gel fouling in membrane bioreactors treating real sewage. CHEMOSPHERE 2022; 309:136557. [PMID: 36185000 DOI: 10.1016/j.chemosphere.2022.136557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 08/29/2022] [Accepted: 09/17/2022] [Indexed: 06/16/2023]
Abstract
The main objective of this study was to investigate the cause of gel fouling in membrane bioreactors (MBRs) treating real sewage in terms of soluble microbial products (SMPs) and microbial aspects. Two anoxic/oxic-MBRs were operated as the control reactor (S1) and the sludge loading rate increased reactor (S2). The reactors were operated under low-temperature around 11 °C conditions. Membrane permeability substantially decreased in S2, and gel layer biofilm was formed on membrane surface. In contrast, the permeability of S1 gradually decreased and cake layer formed. When gel fouling occurred, the protein and polysaccharide of SMP in S2 were 47 and 23 mg L-1, which were significantly lower than those recorded in S1 accounted for 118 and 68 mg L-1, respectively. Furthermore, the total organic carbon concentration of SMPs was 24 mg L-1, which was lower than the influent in S2, accounted for 62 mg L-1. Finally, Campylobacteraceae which exists in sewage and uncultured OD1, dominated the gel layer biofilm in S2, unlike the cake layer biofilm in S1. These results indicated that the gel layer biofilm might be composed of influent substances, demonstrating the importance of influent decomposition in MBR for gel fouling mitigation.
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Affiliation(s)
- Toru Miwa
- Department of Science of Technology Innovation, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, 940-2188, Japan
| | - Yuya Takimoto
- Department of Science of Technology Innovation, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, 940-2188, Japan; Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8566, Japan
| | - Yuki Mizuta
- Department of Civil and Environmental Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, 940-2188, Japan
| | - Masashi Hatamoto
- Department of Civil and Environmental Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, 940-2188, Japan.
| | - Takahiro Watari
- Department of Civil and Environmental Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, 940-2188, Japan
| | - Takashi Yamaguchi
- Department of Science of Technology Innovation, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, 940-2188, Japan; Department of Civil and Environmental Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, 940-2188, Japan
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5
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Chen L, Zhou W, Luo L, Li Y, Chen Z, Gu Y, Chen Q, Deng O, Xu X, Lan T, Gao X, Zhang S, Deng L. Short-term responses of soil nutrients, heavy metals and microbial community to partial substitution of chemical fertilizer with spent mushroom substrates (SMS). THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 844:157064. [PMID: 35780897 DOI: 10.1016/j.scitotenv.2022.157064] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 06/10/2022] [Accepted: 06/26/2022] [Indexed: 06/15/2023]
Abstract
Currently, many spent mushroom substrates (SMS) are produced each year, which have the great potential to replace partial chemical fertilizer in agricultural production due to the high content of organic matter in SMS. However, how the replacement of chemical fertilizer by different SMS affected soil nutrients and contamination was less reported. Therefore, this study applied Enoki mushroom substrates (EMR), Agaricus bisporus substrates (ABR), or Auricularia auricula substrates (AAR) to replace 25 % chemical fertilizers (based on N fertilizer) with understanding the role of SMS replacement in affecting soil nutrients, heavy metals, and microbial community via the short-term field study, respectively. Compared to chemical fertilizer (CF), the contents of organic matter (OM), total P (TP), and K (TK) in SMS replaced soils were significantly increased by 1.96-4.22, 0.08-0.12, and 0.03-0.53 g kg-1, respectively. Among three SMS replacements, AAR demonstrated the highest increment of soil nutrients. On the other hand, EMR and ABR replacements reduced the contents of total and acid-soluble Cd, Pb, and As by 7.94-30.32 % and 0-31.61 % in soils relative to CF, respectively. Unlike EMR and ABR, AAR reduced 11.08-16.04 % of total Cd, Pb, and As but increased 62.58 % acid-soluble As in soils. Furthermore, it was found that all SMS replacements increased the relative abundance of Proteobacteria, while ABR also increased the relative abundance of Actinobacteria in soils compared to CF. Besides, EMR and ABR replacements increased the relative abundance of Mortierellomycota relative to CF. Finally, it can be known that partial replacement of chemical fertilizer by SMS could elevate soil nutrients (especially AAR) and reduce heavy metals (especially EMR), which further improved microbial diversity and community composition. This study provides information on applying SMS to replace partial chemical fertilizer to elevate nutrients and reduce heavy metals contamination.
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Affiliation(s)
- Ludan Chen
- College of Resources, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Wei Zhou
- College of Resources, Sichuan Agricultural University, Chengdu 611130, PR China.
| | - Ling Luo
- College of Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Yirong Li
- College of Resources, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Zhuo Chen
- College of Resources, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Yunfu Gu
- College of Resources, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Qiang Chen
- College of Resources, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Ouping Deng
- College of Resources, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Xiaoxun Xu
- College of Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Ting Lan
- College of Resources, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Xuesong Gao
- College of Resources, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Shirong Zhang
- College of Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Liangji Deng
- College of Resources, Sichuan Agricultural University, Chengdu 611130, PR China
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6
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Li Y, Wang H, Xu C, Sun SH, Xiao K, Huang X. Two strategies of stubborn biofouling strains surviving from NaClO membrane cleaning: EPS shielding and/or quorum sensing. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 838:156421. [PMID: 35660590 DOI: 10.1016/j.scitotenv.2022.156421] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 05/26/2022] [Accepted: 05/30/2022] [Indexed: 06/15/2023]
Abstract
The declined performance of repeated chemically-enhanced-backwashing (CEB) seriously hampered the sustainable operation of membrane bioreactor (MBR) in long-term, and could be partially attributed to the strengthened anti-cleaning properties of residual stubborn microbes. Although plenty of research has been done towards either the model strains or the whole post-CEB microbial community, little was known about the resisting behavior of practical stubborn strains when confronting oxidative stresses induced by NaClO. Hence, this study isolated 21 strains from samples in a large-scale MBR plant with routine CEB treatment. To unravel how they survive and affect membrane fouling, their anti-oxidation ability, fouling potential and quorum sensing (QS) effect before and after NaClO stimuli were evaluated. The composition and molecular weight distribution of extracellular polymeric substance (EPS) were also investigated to understand their roles during the anti-CEB process. It was found that typical stubborn strains tended to secrete more EPS as protective shields, where polysaccharides (especially the ones >1 kDa) made major contribution. However, sometimes EPS could not well resist the stimuli, with consequent low survival rate and high intracellular ROS level. Under such circumstances, stubborn strains would rather choose to be sensitive with surged QS level and quick population regrowth to maintain vitality under the oxidative stresses. Both strategies aggravated biofouling and eventually enhanced the anti-cleaning properties of biofilm.
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Affiliation(s)
- Yufang Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Han Wang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; Beijing OriginWater Membrane Technology Co., Ltd., Product and Technology Center, Beijing 101407, China
| | - Chenyang Xu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Shih-Han Sun
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Kang Xiao
- Beijing Yanshan Earth Critical Zone National Research Station, College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 101408, China.
| | - Xia Huang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; Research and Application Center for Membrane Technology, School of Environment, Tsinghua University, Beijing 100084, China.
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7
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Yan Z, Li A, Shim H, Wang D, Cheng S, Wang Y, Li M. Effect of ozone pretreatment on biogranulation with partial nitritation - Anammox two stages for nitrogen removal from mature landfill leachate. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 317:115470. [PMID: 35751269 DOI: 10.1016/j.jenvman.2022.115470] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 05/28/2022] [Accepted: 05/30/2022] [Indexed: 06/15/2023]
Abstract
Due to the extremely low C/N ratio, high concentration of ammonia nitrogen and refractory organic matter of mature landfill leachate (MLL), appropriate processes should be selected to effectively remove nitrogen and reduce disposal costs. Partial nitritation (PN) and anaerobic ammonia oxidation (AMX) have been used as the main nitrogen removal processes for MLL, and the sludge granulation in PN and AMX processes could contribute to high biological activity, good sedimentation performance, and stable resistance to toxicity. In this study, the O3-PN-AMX biogranules process was selected to effectively remove nitrogen from MLL without carbon addition and pH adjustment. Without uneconomical NH4+-N oxidation and wasting the alkalinity of MLL, ozone pretreatment achieved color removal, decreased humic- and fulvic-like acid substances, and alleviated the MLL toxicity on ammonia oxidizers. In addition, the ozonation of MLL could shorten the start-up time and improve the treatment efficiency and biogranules stability of PN and AMX processes. Efficient and stable nitritation was achieved in PN reactor without strict dissolved oxygen (DO) control, which was attributed to the unique structure of granular sludge, ozone pretreatment, and alternating inhibition of free ammonia and free nitric acid on nitrite oxidizers. Through the application of ozone pretreatment and granular sludge, the nitrogen removal rate (NRR) and nitrogen removal efficiency (NRE) of the O3-PN-AMX biogranules process reached 0.39 kg/m3/day and 85%, respectively, for the undiluted MLL treatment. This study might provide a novel and effective operation strategy of combined process for the efficient, economical, and stable nitrogen removal from MLL.
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Affiliation(s)
- Zhenyu Yan
- Key Laboratory of Water and Sediment Sciences of Ministry of Education / State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China
| | - Anjie Li
- Key Laboratory of Water and Sediment Sciences of Ministry of Education / State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China.
| | - Hojae Shim
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau SAR, 999078, China
| | - Danyang Wang
- Key Laboratory of Water and Sediment Sciences of Ministry of Education / State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China
| | - Shuqian Cheng
- Key Laboratory of Water and Sediment Sciences of Ministry of Education / State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China
| | - Yuexing Wang
- Shenzhen Shenshui Ecological & Environmental Technology Co., Ltd., Shenzhen, 518048, China
| | - Ming Li
- Engelbart (Beijing) Eco-Tech Co., Ltd., Beijing, 101300, China
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Zhou L, Lai Y, Zeng R, Zhao B, Jian Y, Ou P, Zhang W, Ng HY, Zhuang WQ. Core carbon fixation pathways associated with cake layer development in an anoxic-oxic biofilm-membrane bioreactor treating textile wastewater. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 835:155483. [PMID: 35483462 DOI: 10.1016/j.scitotenv.2022.155483] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 04/17/2022] [Accepted: 04/19/2022] [Indexed: 06/14/2023]
Abstract
Microbial carbon fixation pathways have not yet been adequately understood for their role in membrane case layer formation processes. Carbon fixation bacteria can play critical roles in either causing or enhancing cake layer formation in some autotrophic-prone anoxic conditions, such as sulfur-cycling conditions. Understanding the microbes capable of carbon fixation can potentially guide the design of membrane biofouling mitigation strategies in scientific ways. Thus, we used meta-omics methods to query carbon fixation pathways in the cake layers of a full-scale anoxic-oxic biofilm-MBR system treating textile wastewater in this study. Based on the wastewater constituents and other properties, such as anoxic conditions, sulfide-reducing and sulfur-oxidizing bacteria could co-exist in the membrane unit. In addition, low-light radiation conditions could also happen to the membrane unit. However, we could not quantify the light intensity or total energy input accurately because the whole experimental setup was a full-scale system. Potentially complete carbon fixation pathways in the cake layer included the Calvin-Benson-Bassham cycle, Wood-Ljungdahl pathway, and the 3-hydroxypropionate bicycle. We discovered that using aeration could effectively inhibit carbon fixation, which resulted in mitigating membrane cake layer development. However, the aeration resulted in the 3-hydroxypropionate bicycle pathway, presumably used by aerobic sulfur-oxidizing prokaryotes, to become a more abundant carbon fixation pathway in the cake layer under aerobic conditions.
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Affiliation(s)
- Lijie Zhou
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China.
| | - Yongzhou Lai
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Rongjie Zeng
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Bikai Zhao
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Yixin Jian
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Pingxiang Ou
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Wenyu Zhang
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - How Yong Ng
- Centre for Water Research, Department of Civil & Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, 117576, Singapore.
| | - Wei-Qin Zhuang
- Department of Civil and Environmental Engineering, The University of Auckland, Auckland 1142, New Zealand
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9
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Deb A, Gurung K, Rumky J, Sillanpää M, Mänttäri M, Kallioinen M. Dynamics of microbial community and their effects on membrane fouling in an anoxic-oxic gravity-driven membrane bioreactor under varying solid retention time: A pilot-scale study. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 807:150878. [PMID: 34627895 DOI: 10.1016/j.scitotenv.2021.150878] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/24/2021] [Accepted: 10/04/2021] [Indexed: 06/13/2023]
Abstract
Membrane fouling in a membrane bioreactor (MBR) is highly influenced by the characteristics of the influent, the mixed liquor microbial community and the operational parameters, all of which are environment specific. Therefore, we studied the dynamics of microbial community during the treatment of real municipal wastewater in a pilotscale anoxic-oxic (A/O) MBR equipped with a gravity-driven membrane filtration system. The MBR was operated at three different solid retention times (SRTs): 25, 40 and 10 days for a total period of 180 days in Nordic environmental conditions. Analysis of microbial community dynamics revealed a high diversity of microbial species at SRT of 40 days, whereas SRT of 25 days was superior with microbial richness. Production of soluble microbial products (SMP) and extracellular polymeric substances (EPS) was found to be intensely connected with the SRT and food to microorganism (F/M) ratio. Relatively longer operational period with the lowest rate of membrane fouling was observed at SRT of 25 days, which was resulted from the superior microbial community, lowest production of SMP and loosely bound EPS as well as the lower filtration resistance of larger sludge flocs. Abundance of quorum quenching (QQ) bacteria and granular floc forming bacterial genera at SRT of 25 days provided relatively lower membrane fouling tendency and larger floc formation, respectively. On the other hand, substantial amount of various surface colonizing and EPS producing bacteria was found at SRT of 10 days, which promoted more rapid membrane fouling compared with the fouling rate seen at other tested SRTs. To sum up, this research provides a realistic insight into the impact of SRT on microbial community dynamics and resulting characteristics of mixed liquor, floc size distribution and membrane fouling for improved MBR operation.
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Affiliation(s)
- Anjan Deb
- Department of Separation Science, School of Engineering Science, Lappeenranta-Lahti University of Technology (LUT University), Sammonkatu 12, 50130 Mikkeli, Finland; Department of Chemistry, University of Helsinki, P.O. Box 55 (A.I. Virtasen aukio 1), 00014 Helsinki, Finland.
| | - Khum Gurung
- Department of Separation Science, School of Engineering Science, Lappeenranta-Lahti University of Technology (LUT University), Sammonkatu 12, 50130 Mikkeli, Finland
| | - Jannatul Rumky
- Department of Separation Science, School of Engineering Science, Lappeenranta-Lahti University of Technology (LUT University), Sammonkatu 12, 50130 Mikkeli, Finland
| | - Mika Sillanpää
- Department of Chemical Engineering, School of Mining, Metallurgy and Chemical Engineering, University of Johannesburg, P. O. Box 17011, Doornfontein 2028, South Africa; School of Chemical and Metallurgical Engineering, University of the Witwatersrand, 2050 Johannesburg, South Africa; Chemistry Department, College of Science, King Saud University, Riyadh 11451, Saudi Arabia; School of Resources and Environment, University of Electronic Science and Technology of China (UESTC), NO. 2006, Xiyuan Ave., West High-Tech Zone, Chengdu, Sichuan 611731, PR China; Faculty of Science and Technology, School of Applied Physics, University Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia; School of Chemistry, Shoolini University, Solan, Himachal Pradesh 173229, India
| | - Mika Mänttäri
- Department of Separation Science, School of Engineering Science, Lappeenranta-Lahti University of Technology (LUT University), Sammonkatu 12, 50130 Mikkeli, Finland
| | - Mari Kallioinen
- Department of Separation Science, School of Engineering Science, Lappeenranta-Lahti University of Technology (LUT University), Sammonkatu 12, 50130 Mikkeli, Finland
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10
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Zhou L, Dong N, Ye B, Zhuang WQ, Xia S. Assessing effects of Ca 2+ addition on membrane bioreactor performance and macro-floc sludge characteristics. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 798:149223. [PMID: 34375270 DOI: 10.1016/j.scitotenv.2021.149223] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/15/2021] [Accepted: 07/20/2021] [Indexed: 06/13/2023]
Abstract
Calcium ions (Ca2+) can trigger coagulation-flocculation process to form macro-flocculated sludge (MFS). Thus, dosing Ca2+-containing reagents into membrane bioreactors (MBRs) is considered as a promising approach to mitigate membrane biofouling. However, a mechanistic understanding of Ca2+ addition to MBR performance remains elucidated, such as physicochemical characteristics of MFS and their functionality variations. Consequently, this study was sought to understand the interplays of Ca2+ addition and MBR performance with a focus on characterizing MFS in detail. Three parallel MBRs were amended with 82, 208 and 410 mg-Ca2+/L final concentrations. Particle size analyses revealed that MFS formation was overall enhanced by the Ca2+ addition and granular sludge with diameters of up to 900 μm was formed in the 410 mg-Ca2+/L scenario. We believed that cationic bridges facilitated by elevated Ca2+ concentrations in conjunction with coagulation-flocculation were primary mechanisms of the formation of large flocs. Moreover, significant portions of soluble proteins and polysaccharides were flocculated and precipitated by Ca2+, which demonstrated a negative correlation between extracellular polymeric substances (EPS) concentrations and the formation of MFS. Furthermore, the population abundancies of Thiotrichaceae, Sphingomonadales and Hyphomicrobiaceae decreased in the sludge with Ca2+ addition resulted in profound changes of the microbial communities in the MBRs. But MBR performance, such as chemical oxygen demand removal (over 90%), showed no variation during the MBR operation. On the contrary, total nitrogen removal was inhibited in the MBRs. It was because the enlarging MFS formed diffusion barriers to prevent organic component from entering into the sludge flocs to be consumed.
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Affiliation(s)
- Lijie Zhou
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, PR China.
| | - Nan Dong
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, PR China
| | - Biao Ye
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, PR China
| | - Wei-Qin Zhuang
- Department of Civil and Environmental Engineering, University of Auckland, Auckland 1142, New Zealand
| | - Siqing Xia
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, PR China.
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11
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Shao Y, Zhou Z, Jiang J, Jiang LM, Huang J, Zuo Y, Ren Y, Zhao X. Membrane fouling in anoxic/oxic membrane reactors coupled with carrier-enhanced anaerobic side-stream reactor: Effects of anaerobic hydraulic retention time and mechanism insights. J Memb Sci 2021. [DOI: 10.1016/j.memsci.2021.119657] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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