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Mills S, Trego AC, Prevedello M, De Vrieze J, O’Flaherty V, Lens PN, Collins G. Unifying concepts in methanogenic, aerobic, and anammox sludge granulation. ENVIRONMENTAL SCIENCE AND ECOTECHNOLOGY 2024; 17:100310. [PMID: 37705860 PMCID: PMC10495608 DOI: 10.1016/j.ese.2023.100310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Revised: 06/17/2023] [Accepted: 08/05/2023] [Indexed: 09/15/2023]
Abstract
The retention of dense and well-functioning microbial biomass is crucial for effective pollutant removal in several biological wastewater treatment technologies. High solids retention is often achieved through aggregation of microbial communities into dense, spherical aggregates known as granules, which were initially discovered in the 1980s. These granules have since been widely applied in upflow anaerobic digesters for waste-to-energy conversions. Furthermore, granular biomass has been applied in aerobic wastewater treatment and anaerobic ammonium oxidation (anammox) technologies. The mechanisms underpinning the formation of methanogenic, aerobic, and anammox granules are the subject of ongoing research. Although each granule type has been extensively studied in isolation, there has been a lack of comparative studies among these granulation processes. It is likely that there are some unifying concepts that are shared by all three sludge types. Identifying these unifying concepts could allow a unified theory of granulation to be formed. Here, we review the granulation mechanisms of methanogenic, aerobic, and anammox granular sludge, highlighting several common concepts, such as the role of extracellular polymeric substances, cations, and operational parameters like upflow velocity and shear force. We have then identified some unique features of each granule type, such as different internal structures, microbial compositions, and quorum sensing systems. Finally, we propose that future research should prioritize aspects of microbial ecology, such as community assembly or interspecies interactions in individual granules during their formation and growth.
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Affiliation(s)
- Simon Mills
- Microbial Communities Laboratory, School of Biological and Chemical Sciences, National University of Ireland Galway, University Road, Galway, H91 TK33, Ireland
| | - Anna Christine Trego
- Microbial Ecology Laboratory School of Biological and Chemical Sciences, University of Galway, University Road, Galway, H91 TK33, Ireland
| | - Marco Prevedello
- Microbial Communities Laboratory, School of Biological and Chemical Sciences, National University of Ireland Galway, University Road, Galway, H91 TK33, Ireland
| | - Jo De Vrieze
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, B-9000, Gent, Belgium
| | - Vincent O’Flaherty
- Microbial Ecology Laboratory School of Biological and Chemical Sciences, University of Galway, University Road, Galway, H91 TK33, Ireland
| | - Piet N.L. Lens
- University of Galway, University Road, Galway, H91 TK33, Ireland
| | - Gavin Collins
- Microbial Communities Laboratory, School of Biological and Chemical Sciences, National University of Ireland Galway, University Road, Galway, H91 TK33, Ireland
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2
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Cheng L, Wei M, Hu Q, Li B, Li B, Wang W, Abudi ZN, Hu Z. Aerobic granular sludge formation and stability in enhanced biological phosphorus removal system under antibiotics pressure: Performance, granulation mechanism, and microbial successions. JOURNAL OF HAZARDOUS MATERIALS 2023; 454:131472. [PMID: 37099906 DOI: 10.1016/j.jhazmat.2023.131472] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Revised: 04/04/2023] [Accepted: 04/21/2023] [Indexed: 05/19/2023]
Abstract
Wastewater containing antibiotics can pose a significant threat to biological wastewater treatment processes. This study investigated the establishment and stable operation of enhanced biological phosphorus removal (EBPR) by aerobic granular sludge (AGS) under mixed stress conditions induced by tetracycline (TC), sulfamethoxazole (SMX), ofloxacin (OFL), and roxithromycin (ROX). The results show that the AGS system was efficient in removing TP (98.0%), COD (96.1%), and NH4+-N (99.6%). The average removal efficiencies of the four antibiotics were 79.17% (TC), 70.86% (SMX), 25.73% (OFL), and 88.93% (ROX), respectively. The microorganisms in the AGS system secreted more polysaccharides, which contributed to the reactor's tolerance to antibiotics and facilitated granulation by enhancing the production of protein, particularly loosely bound protein. Illumina MiSeq sequencing revealed that putative phosphate accumulating organisms (PAOs)-related genera (Pseudomonas and Flavobacterium) were enormously beneficial to the mature AGS for TP removal. Based on the analysis of extracellular polymeric substances, extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory, and microbial community, a three-stage granulation mechanism was proposed including adaption to the stress environment, formation of early aggregates and maturation of PAOs enriched microbial granules. Overall, the study demonstrated the stability of EBPR-AGS under mixed antibiotics pressure, providing insight into the granulation mechanism and the potential use of AGS for wastewater treatment containing antibiotics.
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Affiliation(s)
- Long Cheng
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Mingyu Wei
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Qixing Hu
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Bingtang Li
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Bo Li
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Wenjia Wang
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zaidun Naji Abudi
- Environmental Engineering Department, College of Engineering, Mustansiriyah University, Baghdad 999048, Iraq
| | - Zhiquan Hu
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
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Li YS, Li BB, Tian T, Yu HQ. Quorum sensing unveils the sludge floccule-assisted stabilization of aerobic granules in granule-dominated sequencing batch reactors. Biotechnol Bioeng 2023; 120:444-455. [PMID: 36303067 DOI: 10.1002/bit.28275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 10/19/2022] [Accepted: 10/23/2022] [Indexed: 01/13/2023]
Abstract
Floccules are another major form of microbial aggregates in aerobic granular sludge systems. Previous studies mainly attributed the persistence of floccules to their relatively faster nutrient uptake and higher growth rate over aerobic granules; however, they failed to unravel the underlying mechanism of the long-term coexistence of these two aggregates. In this work, the existence and function of the floccules in an aerobic granule-dominated sequencing batch reactor were investigated from the view of quorum sensing (QS) and quorum quenching (QQ). The results showed that though the floccules were closely associated with the granules in terms of similar community structures (including the QS- and QQ-related ones), they exhibited a relatively higher QQ-related activity but a lower QS-related activity. A compatible proportion of floccules might be helpful to maintain the QS-related activity and keep the granules stable. In addition, the structure difference was demonstrated to diversify the QS- and QQ-related activities of the floccules and the aerobic granules. These findings could broaden our understanding of the interactions between the coexistent floccules and granules in aerobic granule-dominated systems and would be instructive for the development of the aerobic granular sludge process.
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Affiliation(s)
- Yu-Sheng Li
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science & Technology of China, Hefei, China
| | - Bing-Bing Li
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science & Technology of China, Hefei, China
| | - Tian Tian
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science & Technology of China, Hefei, China.,Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian, China
| | - Han-Qing Yu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science & Technology of China, Hefei, China
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Xiao J, Lin G, Cao Z, Chu S, Cui L, Yang Y, Wu X. A shallow constructed wetland combining porous filter material and Rotala rotundifolia for advanced treatment of municipal sewage at low HRT. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:27593-27602. [PMID: 36383319 DOI: 10.1007/s11356-022-24111-4] [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: 07/07/2022] [Accepted: 11/04/2022] [Indexed: 06/16/2023]
Abstract
Water scarcity is a worldwide problem. Recycled municipal wastewater is considered a useful alternative to the conventional types of water resources. In this study, a shallow constructed wetland (SCW) with porous filter material and Rotala rotundifolia was used for advanced municipal sewage treatment. The wetland without plant was set as the control (SCW-C). The pollutant removal performance of the system at different hydraulic retention times (HRTs) was investigated. The diversity of the microbial community was analyzed, and the fate of nutrients, mainly N and P, in the system was discussed. Results showed that SCW was efficient in pollutant removal. Effluent concentrations of chemical oxygen demand (COD), total phosphorus (TP), and ammonium nitrogen (NH4+-N) were 15.0-23.6, 0.19-0.28, and 0.83-1.16 mg/L, separately, with average removal efficiencies of 61.2%, 46.3%, and 88.1% at HRT 18 h, which met the requirements of type [Formula: see text] water set by the environmental quality standards for surface water in China. The richness and evenness of the bacterial community were significantly higher in the plant-rooted SCW. They increased along with the system. The dominant genera in the system were phosphate-solubilizing bacteria, nitrifying bacteria, and denitrifying bacteria. The P in the influent mainly flowed to the substrate and plant. At the same time, most N was removed by nitrification and denitrification. These findings suggested that the SCW could remove pollutants from the municipal sewage effluent and meet the standard requirement at low HRT.
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Affiliation(s)
- Jibo Xiao
- College of Life and Environmental Science, Wenzhou University, Wenzhou, 325035, China
- National and Local Joint Engineering Research Center of Ecological Treatment Technology for Urban Water Pollution, Wenzhou University, Wenzhou, 325035, China
| | - Guo Lin
- College of Life and Environmental Science, Wenzhou University, Wenzhou, 325035, China
| | - Zhuangzhuang Cao
- College of Life and Environmental Science, Wenzhou University, Wenzhou, 325035, China
| | - Shuyi Chu
- College of Life and Environmental Science, Wenzhou University, Wenzhou, 325035, China.
- National and Local Joint Engineering Research Center of Ecological Treatment Technology for Urban Water Pollution, Wenzhou University, Wenzhou, 325035, China.
- Wenzhou Vocational College of Science and Technology, Wenzhou, 325000, China.
| | - Lingzhou Cui
- College of Life and Environmental Science, Wenzhou University, Wenzhou, 325035, China
- National and Local Joint Engineering Research Center of Ecological Treatment Technology for Urban Water Pollution, Wenzhou University, Wenzhou, 325035, China
| | - Yunlong Yang
- College of Life and Environmental Science, Wenzhou University, Wenzhou, 325035, China
- National and Local Joint Engineering Research Center of Ecological Treatment Technology for Urban Water Pollution, Wenzhou University, Wenzhou, 325035, China
| | - Xiangting Wu
- College of Life and Environmental Science, Wenzhou University, Wenzhou, 325035, China
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Tirkey V, Goonesekera EM, Kovalovszki A, Smets BF, Dechesne A, Valverde-Pérez B. Short sludge age denitrification as alternative process for energy and nutrient recovery. BIORESOURCE TECHNOLOGY 2022; 366:128184. [PMID: 36283659 DOI: 10.1016/j.biortech.2022.128184] [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: 09/04/2022] [Revised: 10/17/2022] [Accepted: 10/18/2022] [Indexed: 06/16/2023]
Abstract
High rate activated sludge (HRAS) systems redirect organics into highly biodegradable sludge and nutrients into microbial proteins. This study evaluates anoxic HRAS for nitrogen and carbon recovery. The reactor treated synthetic wastewater at solids retention times (SRTs) of 5, 3 and 1 days. Denitrification rates varied between 0.15 and 0.19 g-NO3-N g-TSS-1 d-1 (total suspended solids per day) and all conditions showed favourable settling. The highest sludge yield, obtained at SRT 1 d, was 0.75 g-TSS g-CODremoved-1, double that observed for aerobic HRAS. The highest methane yield (322 mL-CH4 g-VSsludge-1) was obtained from sludge wasted at 3 d SRT. Both 1 d and 3 d SRTs showed favourable energy recovery, with 14 % of the organics recovered as methane. All conditions yielded sludge with protein content ranging between 24 and 27 % of dry weight and similar amino acid profile, comparable to traditional proteins. Thus, denitrifying HRAS recovers resources as its aerobic counterpart, allowing for nitrogen removal via denitrification, more stable compared to mainstream partial nitritation anammox typically combined with aerobic HRAS.
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Affiliation(s)
- Vishal Tirkey
- Department of Environmental and Resource Engineering, Technical University of Denmark, DTU, Building 115, Bygningstorvet, 2800 Lyngby, Denmark
| | - Estelle M Goonesekera
- Department of Environmental and Resource Engineering, Technical University of Denmark, DTU, Building 115, Bygningstorvet, 2800 Lyngby, Denmark
| | - Adam Kovalovszki
- Department of Environmental and Resource Engineering, Technical University of Denmark, DTU, Building 115, Bygningstorvet, 2800 Lyngby, Denmark
| | - Barth F Smets
- Department of Environmental and Resource Engineering, Technical University of Denmark, DTU, Building 115, Bygningstorvet, 2800 Lyngby, Denmark
| | - Arnaud Dechesne
- Department of Environmental and Resource Engineering, Technical University of Denmark, DTU, Building 115, Bygningstorvet, 2800 Lyngby, Denmark
| | - Borja Valverde-Pérez
- Department of Environmental and Resource Engineering, Technical University of Denmark, DTU, Building 115, Bygningstorvet, 2800 Lyngby, Denmark.
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Fu HM, Wang J, Ren H, Ding L. Acceleration of start-up of moving bed biofilm reactor at low temperature by adding specialized quorum sensing bacteria. BIORESOURCE TECHNOLOGY 2022; 358:127249. [PMID: 35500834 DOI: 10.1016/j.biortech.2022.127249] [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: 03/14/2022] [Revised: 04/25/2022] [Accepted: 04/27/2022] [Indexed: 06/14/2023]
Abstract
This study aims to accelerate biofilm formation and operational performance of moving bed biofilm reactor (MBBR) at 5 ℃ by adding specialized Quorum Sensing bacteria (sphingomonas rubra BH3T). Results showed that bio augmented MBBR (RS) achieved a higher chemical oxygen demand and NH4+-N removal rate (93% and 75%), which in accordance with its increased biofilm thickness, higher biofilm activity, and nitrifying bacteria abundance (Nitrospira). The increased biofilm thickness (60.23 %) during the whole operating time, accompanied by more potent adhesion force (61.59 %), was related to increased polysaccharides and proteins in the biofilm. Pyrosequencing analysis indicated that BH3T contributed to higher species richness and triggered the rapid growth of precursor microorganisms (Nakamurella, Micropruina, and Zoogloea) and the enrichment of multifunctional microorganisms (Pseudomonas, Aeromonas, Arcobacter, Dechloromonas, and Flavobacterium) at low temperatures. This study provides an economical and practical new insight into accelerating start-up of MBBR system at low temperature.
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Affiliation(s)
- Hui-Min Fu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Jinfeng Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Hongqiang Ren
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Lili Ding
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China.
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7
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Zhao JR, Fan XY, Li X, Gao YX, Zhang ZX. Impact of ciprofloxacin and copper combined pollution on activated sludge: Abundant-rare taxa and antibiotic resistance genes. BIORESOURCE TECHNOLOGY 2022; 349:126882. [PMID: 35217161 DOI: 10.1016/j.biortech.2022.126882] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 02/15/2022] [Accepted: 02/17/2022] [Indexed: 06/14/2023]
Abstract
This study aimed to explore the impacts of ciprofloxacin (CIP, 0.05-40 mg/L) and copper (3 mg/L) combined pollution on nitrification, microbial community and antibiotic resistance genes (ARGs) in activated sludge system during stress- and post-effect periods. Higher CIP concentration inhibited nitrification and an average of 50% total nitrogen removal occurred under 40 mg/L of CIP pressure. The stress- and post-effects on bacterial diversity and structure were obviously distinct. Abundant genera were more sensitive to combined pollution than rare genera based on full-scale classification and conditionally rare or abundant taxa were keystone taxa in their interactions. Ammonia oxidation genes were inhibited under high CIP level, but some aerobic denitrifying bacteria (Thauera, Comamonas and Azoarcus) and key genes increased. 96 ARG subtypes were detected with complex positive relationships and their potential hosts (abundant-rare-functional genera) changed in two periods. This study highlights the different stress- and post-effects of combined pollution on activated sludge.
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Affiliation(s)
- Jun-Ru Zhao
- Faculty of Architecture, Civil and Transportation Engineering, Beijing University of Technology, Beijing 100124, PR China
| | - Xiao-Yan Fan
- Faculty of Architecture, Civil and Transportation Engineering, Beijing University of Technology, Beijing 100124, PR China.
| | - Xing Li
- Faculty of Architecture, Civil and Transportation Engineering, Beijing University of Technology, Beijing 100124, PR China
| | - Yu-Xi Gao
- Faculty of Architecture, Civil and Transportation Engineering, Beijing University of Technology, Beijing 100124, PR China
| | - Zhong-Xing Zhang
- Faculty of Architecture, Civil and Transportation Engineering, Beijing University of Technology, Beijing 100124, PR China
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8
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Yan R, Wang Y, Li J, Wang X, Wang Y. Determination of the lower limits of antibiotic biodegradation and the fate of antibiotic resistant genes in activated sludge: Both nitrifying bacteria and heterotrophic bacteria matter. JOURNAL OF HAZARDOUS MATERIALS 2022; 425:127764. [PMID: 34799165 DOI: 10.1016/j.jhazmat.2021.127764] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 10/05/2021] [Accepted: 11/09/2021] [Indexed: 06/13/2023]
Abstract
Antibiotics can be biodegraded in activated sludge via co-metabolism and metabolism. In this study, we investigated the biodegradation pathways of sulfamethoxazole (SMX) and antibiotic resistant genes' (ARGs) fate in different autotrophic and heterotrophic microorganisms, by employing aerobic sludge, mixed sludge, and nitrifying sludge. A threshold concentration of SMX activating the degradation pathways in the initial stage of antibiotics degradation was found and proved in different activated sludge systems. Heterotrophic bacteria played an important role in SMX biodegradation. However, ammonia-oxidizing bacteria (AOB) had a faster metabolic rate, which was about 15 times higher than heterotrophic bacteria, contributing much to SMX removal via co-metabolism. As SMX concentration increases, the amoA gene and AOB relative abundance decreased in aerobic sludge due to the enrichment of functional heterotrophic bacteria, while it increased in nitrifying sludge. Microbial community analysis showed that functional bacteria which possess the capacity of SMX removal and antibiotic resistance were selected by SMX pressure. Potential ARGs hosts could increase their resistance to the biotoxicity of SMX and maintain system performance. These findings are of practical significance to guide antibiotic biodegradation and ARGs control in wastewater treatment plants.
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Affiliation(s)
- Ruofan Yan
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China
| | - Yibing Wang
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China
| | - Jiahuan Li
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China
| | - Xinhua Wang
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China.
| | - Yunkun Wang
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China; Chinese Academy of Science Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China.
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9
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Sarvajith M, Nancharaiah YV. Enhancing biological nitrogen and phosphorus removal performance in aerobic granular sludge sequencing batch reactors by activated carbon particles. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 303:114134. [PMID: 34839174 DOI: 10.1016/j.jenvman.2021.114134] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 11/18/2021] [Accepted: 11/18/2021] [Indexed: 06/13/2023]
Abstract
Long start-up periods for aerobic granular sludge (AGS) formation and establishment of P removal pathways are challenges for widespread implementation of AGS process. External additives such as activated carbon (AC) attracted interest for accelerating AGS formation. However, the roles of AC in granulation and biological nutrient removal (BNR) are not understood. Here, the role of AC was investigated in decreasing start-up periods in AGS formation and BNR under different carbon substrate conditions (i.e., acetate (HAc), propionate (HPr) and HAc-HPr) in sequencing batch reactors (SBRs). AC addition increased aggregation index and settleability of activated sludge (AS) inoculum which minimized AS washout from SBRs. AC addition hastened AGS formation and establishment of BNR pathways by facilitating AS retention and biofilm formation. Feeding HAc or HAc-HPr supported better granulation (MLSS: 6-7 g l-1, SVI: 30-40 ml g-1) than HPr (MLSS: 4 g l-1, SVI: 70). The start-up periods for efficient total nitrogen (TN) removals were decreased to 22 and 16 d from 38 to 25 d, respectively, in AC augmented SBRs fed with either HAc or HAc-HPr. TN removals were higher at ≥95% in HAc or HAc-HPr fed SBRs. Total phosphorus (TP) removals were also higher in AC-augmented SBRs at 80% and ≥90% in HAc and HAc-HPr fed SBRs, respectively. In contrast, TN and TP removals were lower at 70% and 35%, respectively, in HPr fed SBR. Ammonium was primarily removed via nitritation-denitritation pathway. Phosphorus removal was at 1.7 to 2-fold higher in AC augmented SBRs and driven by enhanced biological phosphorus removal (EBPR) pathway. MiSeq sequencing and qPCR revealed higher enrichment of polyphosphate accumulating organisms (PAOs), denitrifying PAOs, and ammonia oxidizers in AC-augmented SBRs fed with HAc or HAc-HPr. This study demonstrates that AC addition can be considered for enrichment of PAOs and establishment of EBPR in aerobic granular SBRs.
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Affiliation(s)
- M Sarvajith
- Biofouling and Biofilm Processes Section, WSCD, Chemistry Group, Bhabha Atomic Research Centre, Kalpakkam, 603102, Tamil Nadu, India; Homi Bhabha National Institute, BARC Training School Complex, Anushakti Nagar, Trombay, Mumbai, 400 094, India
| | - Y V Nancharaiah
- Biofouling and Biofilm Processes Section, WSCD, Chemistry Group, Bhabha Atomic Research Centre, Kalpakkam, 603102, Tamil Nadu, India; Homi Bhabha National Institute, BARC Training School Complex, Anushakti Nagar, Trombay, Mumbai, 400 094, India.
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10
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Hamiruddin NA, Awang NA, Mohd Shahpudin SN, Zaidi NS, Said MAM, Chaplot B, Azamathulla HM. Effects of wastewater type on stability and operating conditions control strategy in relation to the formation of aerobic granular sludge - a review. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2021; 84:2113-2130. [PMID: 34810301 DOI: 10.2166/wst.2021.415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Currently, research trends on aerobic granular sludge (AGS) have integrated the operating conditions of extracellular polymeric substances (EPS) towards the stability of AGS systems in various types of wastewater with different physical and biochemical characteristics. More attention is given to the stability of the AGS system for real site applications. Although recent studies have reported comprehensively the mechanism of AGS formation and stability in relation to other intermolecular interactions such as microbial distribution, shock loading and toxicity, standard operating condition control strategies for different types of wastewater have not yet been discussed. Thus, the dimensional multi-layer structural model of AGS is discussed comprehensively in the first part of this review paper, focusing on diameter size, thickness variability of each layer and diffusion factor. This can assist in facilitating the interrelation between disposition and stability of AGS structure to correspond to the changes in wastewater types, which is the main objective and novelty of this review.
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Affiliation(s)
- N A Hamiruddin
- School of Civil Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang, Malaysia E-mail:
| | - N A Awang
- School of Civil Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang, Malaysia E-mail:
| | - S N Mohd Shahpudin
- Advanced Medical and Dental Institute, Universiti Sains Malaysia, 13200 Kepala Batas, Penang, Malaysia
| | - N S Zaidi
- School of Civil Engineering, Faculty of Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Malaysia
| | - M A M Said
- School of Civil Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang, Malaysia E-mail:
| | - B Chaplot
- Department of Geography, M.J.K College, Bettiah, a constituent unit of B.R.A., Bihar University, Bettiah, Muzaffarpur, India
| | - H M Azamathulla
- Faculty of Engineering, The University of the West Indies, St. Augustine, Trinidad
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11
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Zhu M, Zhang M, Yuan Y, Zhang P, Du S, Ya T, Chen D, Wang X, Zhang T. Responses of microbial communities and their interactions to ibuprofen in a bio-electrochemical system. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 289:112473. [PMID: 33819654 DOI: 10.1016/j.jenvman.2021.112473] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 02/07/2021] [Accepted: 03/20/2021] [Indexed: 06/12/2023]
Abstract
Ibuprofen has caused great concerns due to their potential environmental risks. However, their removal efficiency and their effects on microbial interactions in bio-electrochemical system remain unclear. To address these issues, a lab-scale bio-electrochemical reactor integrated with sulfur/iron-mediated autotrophic denitrification (BER-S/IAD) system exposing to 1000 μg L-1 ibuprofen was operated for about two months. Results revealed that the BER-S/IAD system obtained efficient simultaneous denitrification (98.93%) and phosphorus (82.67%) removal, as well as an excellent ibuprofen removal performance (96.98%). Ibuprofen had no significant impacts on the nitrate (NO3--N) removal and the ammonia (NH4+-N) accumulation, but decreased the total nitrogen (TN) and total phosphorus (TP) removal efficiencies. MiSeq sequencing analysis revealed that ibuprofen significantly (P < 0.05) decreased the microbial community diversity and changed their overall structure. Some bacteria related to denitrification and phosphorus removal, such as Pseudomonas and Thiobacillus, decreased significantly (P < 0.05). Moreover, molecular ecological network (MEN) analysis revealed that ibuprofen decreased the network's size and complexity, and enhanced the negative correlations of Proteobacteria and Firmicutes. Besides, ibuprofen decreased the links of some keystone bacteria related to denitrification and phosphorus removal. This research could provide a new dimension for our comprehending of the responses of microbial communities and their interactions to ibuprofen in bio-electrochemical system.
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Affiliation(s)
- Minghan Zhu
- Key Laboratory of Cleaner Production and Integrated Resource Utilization of China National Light Industry, Beijing Technology and Business University, Beijing, 100048, China; Beijing Engineering Research Center of Environmental Material for Water Purification, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, 100029, China; School of Environment and Energy, South China University of Technology, Guangzhou, 510006, China
| | - Minglu Zhang
- Key Laboratory of Cleaner Production and Integrated Resource Utilization of China National Light Industry, Beijing Technology and Business University, Beijing, 100048, China
| | - Yibo Yuan
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, China
| | - Peilin Zhang
- Beijing Engineering Research Center of Environmental Material for Water Purification, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Shuai Du
- Beijing Guo Dian Fu Tong Science and Technology Development Co., Ltd., Beijing, 100090, China
| | - Tao Ya
- Beijing Engineering Research Center of Environmental Material for Water Purification, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Daying Chen
- Beijing Engineering Research Center of Environmental Material for Water Purification, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Xiaohui Wang
- Beijing Engineering Research Center of Environmental Material for Water Purification, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, 100029, China.
| | - Tingting Zhang
- Beijing Engineering Research Center of Environmental Material for Water Purification, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, 100029, China.
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12
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Zhao ZQ, Wei XM, Shen XL, Abbas G, Fan R, Jin Y. Aerobic degradation of 4-fluoroaniline and 2,4-difluoroaniline: performance and microbial community in response to the inocula. Biodegradation 2021; 32:53-71. [PMID: 33428058 DOI: 10.1007/s10532-021-09925-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Accepted: 01/02/2021] [Indexed: 11/27/2022]
Abstract
In this study, a distinct inoculum was investigated as an isolated variable within sequencing batch reactors via a comparison of the 4-fluoroaniline (4-FA) or 2,4-difluoroaniline (2,4-DFA) removal amounts. The inocula were derived from a treatment plant for treating pharmaceutical wastewater plus a small amount of municipal sewage (PMS), a treatment plant for treating fluoridated hydrocarbon wastewater (FHS), and a treatment plant for treating the comprehensive wastewater in an industrial park (CIS). There were slight differences among the degradation patterns of the 4-FA for the three inocula, whether during the enrichment period or the high concentration shock period. In contrast, it was observed that the degradation efficiency of 2,4-DFA initially varied with the inocula. The FHS-derived inoculum was determined to be optimal, exhibiting the earliest degradation reaction only after an acclimation of 7 days had the highest degradation rate constant of 0.519 h-1, and had the fastest recovery time of three weeks after high concentration shock. Additionally, compared with the PMS-derived inoculum, the CIS-derived inoculum exhibited an earlier degradation reaction within three weeks, and a higher microbial diversity, but a lower shock resistance and degradation rate constant of 0.257 h-1. High-throughput sequencing demonstrated that each final consortium was different in composition, and the microbial consortia developed well on the inoculum and substrate. In comparison of the similarity among the three 2,4-DFA enrichment cultures, the higher similarity (63.9-70.0%) among three final consortia enriching with 4-FA was observed. The results indicated that the inoculum played an important role in the degradation of FAs and the microbial bacterial communities of final consortia, and the effect extent might well depend on the fluorinated level of FAs.
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Affiliation(s)
- Zhi-Qing Zhao
- College of Chemical & Material Engineering, Quzhou University, Quzhou, 324000, People's Republic of China. .,College of Environment & Resource Sciences, Zhejiang University, Hangzhou, People's Republic of China.
| | - Xiao-Meng Wei
- Key Laboratory of Agro-Ecological Processes in Subtropical Region & Changsha Research Station for Agricultural and Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, China
| | - Xiao-Li Shen
- College of Chemical & Material Engineering, Quzhou University, Quzhou, 324000, People's Republic of China
| | - Ghulam Abbas
- Department of Chemical Engineering, University of Gujrat, Gujrat, 50700, Pakistan
| | - Rui Fan
- College of Chemical & Material Engineering, Quzhou University, Quzhou, 324000, People's Republic of China
| | - Yi Jin
- College of Chemical & Material Engineering, Quzhou University, Quzhou, 324000, People's Republic of China
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13
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Xiong W, Wang S, Zhou N, Chen Y, Su H. Granulation enhancement and microbial community shift of tylosin-tolerant aerobic granular sludge on the treatment of tylosin wastewater. BIORESOURCE TECHNOLOGY 2020; 318:124041. [PMID: 32889122 DOI: 10.1016/j.biortech.2020.124041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/18/2020] [Accepted: 08/19/2020] [Indexed: 06/11/2023]
Abstract
To reduce the environment pollution from the extensive use of tylosin (TYL), in this study, an antibiotic adaptive strategy was used to enhance the TYL tolerance of aerobic granular sludge (AGS) for the treatment of TYL wastewater. The results showed that the granulation process was enhanced after 30 days of operation. The TYL-tolerant AGS gradually formed and maintained a diameter of 1.2 mm, with the mixed liquor suspended solids (MLSS) of 6810 mg⋅L-1 and sludge volume index (SVI) of 26 mL⋅g-1. Meanwhile, the chemical oxygen demand (COD), NH4+-N, and total N removal effiencies could reach up to 92.9%, 91.7%, 88.5%, respectively. The average TYL removal rate was 85.5% with the effuent TYL of 1.45 mg⋅L-1. In addition, the microbial communities shifted significantly that Bacteroidetes and Proteobacteria dominated the phylm, and the Macellibacteroides was the major genus which might possess the anitibiotic resistance genes of TYL.
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Affiliation(s)
- Wei Xiong
- Beijing Key Laboratory of Bioprocess, and Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
| | - Shaojie Wang
- Beijing Key Laboratory of Bioprocess, and Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China; Institute of Nano Biomedicine and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
| | - Nan Zhou
- Beijing Key Laboratory of Bioprocess, and Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
| | - Yingyun Chen
- Beijing Key Laboratory of Bioprocess, and Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
| | - Haijia Su
- Beijing Key Laboratory of Bioprocess, and Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China.
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14
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Wang L, Zhan H, Wu G, Zeng Y. Effect of operational strategies on the rapid start-up of nitrogen removal aerobic granular system with dewatered sludge as inoculant. BIORESOURCE TECHNOLOGY 2020; 315:123816. [PMID: 32688252 DOI: 10.1016/j.biortech.2020.123816] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 07/03/2020] [Accepted: 07/06/2020] [Indexed: 06/11/2023]
Abstract
In both sequencing batch reactors with dewatering sludge as inoculant, the strategies by step-feeding (R1) or step-feeding combined with low aeration (R2) were performed under alternating anoxic/aerobic condition to discover superior methods launching nitrogen removal aerobic granule system. Interestingly, two reactors accomplished granulation at day 0, two days later, possessed prominent settling performance (SVI < 45 ml/g. MLSS) and denitrifying ability (TIN > 80%). Thereinto, R2 had lower crushing rate, larger granules, higher biomass and better pollutant removal performance owing to low aeration and more filamentous bacteria on AGS surface. Moreover, effluent NH4+-N was used as indicator of excess filaments due to its quick response for the filaments. After effluent NH4+-N exceeded 5 mg/L, causative filaments Sphaerotilus were effectively inhibited and eliminated by enhancing pH value to 8.0 ± 0.2. As a result, this study provides a new insight into rapid start-up nitrogen removal granule system by promoting and limiting filaments in proper period.
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Affiliation(s)
- Lei Wang
- School of Civil Engineering, Southwest Jiaotong University, 610031 Chengdu, China; School of Environment Science and Spatial Informatics, China University of Mining and Technology, 221116 Xuzhou, China.
| | - Hanhui Zhan
- School of Environment Science and Spatial Informatics, China University of Mining and Technology, 221116 Xuzhou, China
| | - Gang Wu
- School of Life Science and Engineering, Southwest Jiaotong University, 610031 Chengdu, China
| | - Yong Zeng
- School of Civil Engineering, Southwest Jiaotong University, 610031 Chengdu, China
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15
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Composted Chicken Manure for Anaerobic Soil Disinfestation Increased the Strawberry Yield and Shifted the Soil Microbial Communities. SUSTAINABILITY 2020. [DOI: 10.3390/su12166313] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Anaerobic soil disinfestation (ASD), as a bio-fumigation technology, has been developed to control soil-borne pests. There is increasing evidence showing that carbon sources and cover tarps play an important role in the ASD suppression of soil-borne pests, but little is known about the effect of composted chicken manure (CCM) and totally impermeable films (TIF) against soil-borne pests in the strawberry production system. In experiments, the colonies of Fusarium spp. and Phytophthora spp., which are recognized to cause strawberry soil-borne diseases, decreased significantly after ASD. The soil promoted a significant increase in ammonium nitrogen, nitrate-nitrogen and organic matter, but a decrease in oxidation-reduction potential after ASD. Besides, the strawberry plant height, stem thickness and yield were significantly higher than in the non-amended soil. Compared to the untreated control, ASD, both at 6 and 12 ton/ha of CCM, significantly (p = 0.05) increased strawberry marketable yield and income. The economic benefit could be due to the suppression of soil-borne diseases and the improvement of soil nutrition. The soil bacterial and fungal diversity and richness increased after soil fumigation. The increased presence of biological control agents led to the suppression of soil-borne pathogens. In summary, ASD with CCM amendments could be applied in pre-plant fumigation to control strawberry soil-borne pests, strengthen soil fertility, improve crop yield and increase growers’ income.
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16
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Wei SP, Stensel HD, Nguyen Quoc B, Stahl DA, Huang X, Lee PH, Winkler MKH. Flocs in disguise? High granule abundance found in continuous-flow activated sludge treatment plants. WATER RESEARCH 2020; 179:115865. [PMID: 32388048 DOI: 10.1016/j.watres.2020.115865] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 04/19/2020] [Accepted: 04/21/2020] [Indexed: 06/11/2023]
Abstract
To date, high performance of full-scale aerobic granular sludge (AGS) technology has been demonstrated on a global scale. Its further integration with existing continuous flow activated sludge (CFAS) treatment plants is the next logical step. All granular sludge reactors operated in sequencing batch reactors (SBR) mode with anaerobic feeding conditions select for growth of phosphorus and glycogen accumulating organisms (PAO and GAO, respectively), which are known to enhance sludge settling characteristics. Therefore, we hypothesized that AGS are commonly present at full-scale CFAS processes with enhanced biological phosphorus removal (EBPR) and low sludge volume index (SVI). This hypothesis was confirmed at 13 EBPR plants, where granules were found present (at plants where SVI was lower than 100 ml/g) with a strong correlation between high granule abundance and low SVI. A wide range of granule abundance was found among the plants, ranging from 0.5% to as high as 80%. Evaluations of the EBPR plant process configurations showed that high granule abundances may be related to selector design features such as high anaerobic food to mass (F/M) ratios, unmixed in-line fermentation, and high influent soluble COD fraction. Granules were also observed at a non-EBPR plant with an aerobic selector receiving high F/M feeds. Quantitative PCR and 16S rRNA gene sequencing analyses revealed higher relative gene abundance of Accumulibacter PAO and Competibacter GAO in the granules over flocs, as well as a correlation between granule abundance and some possible EPS producers such as Flavobacterium and Competibacter. Our results indicated that process configurations that select for slow-growing or EPS-producing heterotrophs play an important role for granule formation in full-scale CFAS systems as previously shown in SBR configurations.
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Affiliation(s)
- Stephany P Wei
- University of Washington, Department of Civil & Environmental Engineering, 616 NE Northlake Place, Seattle, WA, 98195, USA.
| | - H David Stensel
- University of Washington, Department of Civil & Environmental Engineering, 616 NE Northlake Place, Seattle, WA, 98195, USA.
| | - Bao Nguyen Quoc
- University of Washington, Department of Civil & Environmental Engineering, 616 NE Northlake Place, Seattle, WA, 98195, USA.
| | - David A Stahl
- University of Washington, Department of Civil & Environmental Engineering, 616 NE Northlake Place, Seattle, WA, 98195, USA.
| | - Xiaowu Huang
- Hong Kong Polytechnic University, Department of Civil and Environmental Engineering, 11 Yuk Choi Rd, Hung Hom, Hong Kong.
| | - Po-Heng Lee
- Hong Kong Polytechnic University, Department of Civil and Environmental Engineering, 11 Yuk Choi Rd, Hung Hom, Hong Kong.
| | - Mari-K H Winkler
- University of Washington, Department of Civil & Environmental Engineering, 616 NE Northlake Place, Seattle, WA, 98195, USA.
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17
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Spasov E, Tsuji JM, Hug LA, Doxey AC, Sauder LA, Parker WJ, Neufeld JD. High functional diversity among Nitrospira populations that dominate rotating biological contactor microbial communities in a municipal wastewater treatment plant. THE ISME JOURNAL 2020; 14:1857-1872. [PMID: 32332864 PMCID: PMC7305129 DOI: 10.1038/s41396-020-0650-2] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 03/03/2020] [Accepted: 03/30/2020] [Indexed: 01/31/2023]
Abstract
Nitrification, the oxidation of ammonia to nitrate via nitrite, is an important process in municipal wastewater treatment plants (WWTPs). Members of the Nitrospira genus that contribute to complete ammonia oxidation (comammox) have only recently been discovered and their relevance to engineered water treatment systems is poorly understood. This study investigated distributions of Nitrospira, ammonia-oxidizing archaea (AOA), and ammonia-oxidizing bacteria (AOB) in biofilm samples collected from tertiary rotating biological contactors (RBCs) of a municipal WWTP in Guelph, Ontario, Canada. Using quantitative PCR (qPCR), 16S rRNA gene sequencing, and metagenomics, our results demonstrate that Nitrospira species strongly dominate RBC biofilm samples and that comammox Nitrospira outnumber all other nitrifiers. Genome bins recovered from assembled metagenomes reveal multiple populations of comammox Nitrospira with distinct spatial and temporal distributions, including several taxa that are distinct from previously characterized Nitrospira members. Diverse functional profiles imply a high level of niche heterogeneity among comammox Nitrospira, in contrast to the sole detected AOA representative that was previously cultivated and characterized from the same RBC biofilm. Our metagenome bins also reveal two cyanase-encoding populations of comammox Nitrospira, suggesting an ability to degrade cyanate, which has only been shown previously for several Nitrospira representatives that are strict nitrite oxidizers. This study demonstrates the importance of RBCs as model systems for continued investigation of environmental factors that control the distributions and activities of AOB, AOA, comammox Nitrospira, and other nitrite oxidizers.
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Affiliation(s)
- Emilie Spasov
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
| | - Jackson M Tsuji
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
| | - Laura A Hug
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
| | - Andrew C Doxey
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
| | - Laura A Sauder
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
| | - Wayne J Parker
- Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, ON, Canada
| | - Josh D Neufeld
- Department of Biology, University of Waterloo, Waterloo, ON, Canada.
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18
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Li DC, Gao JF, Zhang SJ, Gao YQ, Sun LX. Emergence and spread patterns of antibiotic resistance genes during two different aerobic granular sludge cultivation processes. ENVIRONMENT INTERNATIONAL 2020; 137:105540. [PMID: 32032776 DOI: 10.1016/j.envint.2020.105540] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 01/25/2020] [Accepted: 01/29/2020] [Indexed: 05/15/2023]
Abstract
The prevalence and accumulation of antibiotic resistance genes (ARGs) were frequently detected in biological wastewater treatment processes, which might cause potential health crisis to human. In present study, the fates of ARGs during two different aerobic granular sludge (AGS) cultivation processes were investigated. The results showed that traditional AGS (T-AGS) cultivation process and enhanced AGS (E-AGS) cultivation process had significant differences (P < 0.005) in ARGs shift patterns. E-AGS process had higher average relative abundance (0.280 ± 0.079) of ARGs than T-AGS process (0.130 ± 0.041), while the intensity of ARGs enrichment during E-AGS (1.52-5.29 fold) was lower than T-AGS (3.79-75.31 fold) process. TnpA and intI1 as two different types of mobile genetic elements (MGEs) carrying ARGs, were observed to contribute significantly to the horizontal gene transfer (HGT) during T-AGS (r = 0.902, P < 0.050) and E-AGS (r = 0.823, P < 0.001) processes, respectively. Higher HGT level took place and more possible potential hosts (25 hosts) harboring ARGs were detected during E-AGS process comparing with T-AGS process (17 hosts). Meanwhile, over large AGS might increase the propagation of several antibiotic deactivation ARGs, so it was not advised. Overall, whether during T-AGS or during E-AGS process which was applied in a pilot-scale sequencing batch reactor treating municipal wastewater, the accumulation and spread of ARGs were inevitable. It should be valued that some suitable pre-treatments of seed sludge should be executed, meanwhile, advanced treatment for removing of ARGs in AGS should be conducted to maintain the relative abundances of ARGs at relatively low level.
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Affiliation(s)
- Ding-Chang Li
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, China
| | - Jing-Feng Gao
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, China.
| | - Shu-Jun Zhang
- Research and Development Center of Beijing Drainage Group Co. Ltd, Beijing 100124, China
| | - Yong-Qing Gao
- Research and Development Center of Beijing Drainage Group Co. Ltd, Beijing 100124, China
| | - Li-Xin Sun
- Research and Development Center of Beijing Drainage Group Co. Ltd, Beijing 100124, China
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19
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Li DC, Gao JF, Zhang SJ, Gao YQ, Sun LX. Enhanced granulation process, a more effective way of aerobic granular sludge cultivation in pilot-scale application comparing to normal granulation process: From the perspective of microbial insights. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 707:136106. [PMID: 31863990 DOI: 10.1016/j.scitotenv.2019.136106] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 12/11/2019] [Accepted: 12/11/2019] [Indexed: 06/10/2023]
Abstract
Aerobic granular sludge (AGS) could be cultivated from only flocs (called normal granulation (NG) process) or mixture of flocs and crushed AGS (called enhanced granulation (EG) process), which might lead to different system performances such as granulation speed and pollutants removal efficiencies. However, the differences of mechanisms between NG and EG processes at microbial community level are still unknown. In this study, the NG and EG processes were implemented successively in a pilot-scale sequencing batch reactor (SBR) with certain amounts of additional carbon sources. Illumina MiSeq sequencing and quantitative PCR were applied to investigate the dynamics of bacterial communities during NG and EG processes and explore the possible explanations for faster EG process. The results showed that significant distinctions in bacterial diversities and community structures were observed between NG and EG processes. The major contributor to NG process was bacterial communities with 32.04% contribution. While EG process was more dependent on the interactions (73.16% contribution) between the bacterial communities and environmental variables (operational parameters and self-adaptive variable). EG process had higher relative abundances of functional bacteria than NG process. Glycogen accumulating organisms (GAOs) related bacteria with a total relative abundance of maximum 65.43% might be mainly responsible for the faster EG process. This study provided microbial insights for practical application of AGS technology that inoculating crushed AGS might be an effective way to cultivate AGS.
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Affiliation(s)
- Ding-Chang Li
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, China
| | - Jing-Feng Gao
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, China.
| | - Shu-Jun Zhang
- Research and Development Center of Beijing Drainage Group Co. Ltd, Beijing 100124, China
| | - Yong-Qing Gao
- Research and Development Center of Beijing Drainage Group Co. Ltd, Beijing 100124, China
| | - Li-Xin Sun
- Research and Development Center of Beijing Drainage Group Co. Ltd, Beijing 100124, China
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20
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Barros ARM, Rollemberg SLDS, de Carvalho CDA, Moura IHH, Firmino PIM, Dos Santos AB. Effect of calcium addition on the formation and maintenance of aerobic granular sludge (AGS) in simultaneous fill/draw mode sequencing batch reactors (SBRs). JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 255:109850. [PMID: 31760299 DOI: 10.1016/j.jenvman.2019.109850] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 09/26/2019] [Accepted: 11/10/2019] [Indexed: 06/10/2023]
Abstract
This work investigated the effect of Ca2+ (100 mg L-1) addition on the formation and maintenance of aerobic granular sludge in a simultaneous fill/draw mode sequencing batch reactor (SBR), operated with a low liquid upflow velocity (0.92 m h-1), in order to verify if Ca2+ presence compensates the low selection pressure imposed. Additionally, carbon and nutrients removals, granules characteristics and microbial community were evaluated. For this, two SBRs (R1, control, and R2, Ca2+-supplemented) were operated (6-h cycle). In general, Ca2+ supplementation affected positively the sludge settleability, although a larger fraction of inert solids was found in the granules. The total extracellular polymeric substances were the same for both reactors, and no remarkable differences were observed between their polysaccharides and proteins contents. Overall, Ca2+ addition in a simultaneous fill/draw mode SBR neither accelerated the granule formation nor improved the operational performance. The microbial community structure, especially in terms of bioactivity, was not affected as well. Therefore, the effect of divalent cations might be more pronounced in conventional SBRs, in which the selection pressure is higher.
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Affiliation(s)
| | | | - Clara de Amorim de Carvalho
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - Ian Holanda Herbster Moura
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - Paulo Igor Milen Firmino
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - André Bezerra Dos Santos
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil.
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21
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Zhang B, Li W, Guo Y, Zhang Z, Shi W, Cui F, Lens PNL, Tay JH. A sustainable strategy for effective regulation of aerobic granulation: Augmentation of the signaling molecule content by cultivating AHL-producing strains. WATER RESEARCH 2020; 169:115193. [PMID: 31670083 DOI: 10.1016/j.watres.2019.115193] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 10/05/2019] [Accepted: 10/13/2019] [Indexed: 06/10/2023]
Abstract
The positive roles of N-acyl homoserine lactone (AHL)-mediated quorum sensing (QS) in aerobic granular sludge (AGS) have been widely acknowledged. However, it is not feasible to manipulate granulation via direct addition of AHL chemicals or AHL-producing strains. Here, several strains with high AHL-producing capacity were successfully isolated from AGS. These QS strains were cultivated, mixed as a consortium, and then divided into two groups: AHLs supernatant and bacterial cells encapsulated in sodium alginate (CEBs). The potential of QS regulation, via doses of AHLs supernatant and CEBs, in accelerating granulation was evaluated. Results clearly indicated that short-term (days 21-70) addition of AHLs supernatant led to a rapid specific growth rate (0.08 d-1), compact structure without filamentous bacteria overgrowth, excellent settlement performance (SVI10 37.2 mL/g), and a high integrity coefficient (4.4%) of the granules. Sustainable release of AHLs (mainly C6- and C8-HSL) was induced by exogenous AHLs, possibly attributed to the enrichment of the genera Aeromonas and Pseudomonas. Further, tryptophan and aromatic protein substances were produced to maintain structural stability, suggesting that short-term QS regulation had long-term positive effects on the characteristics of AGS. By comparison, the addition of CEBs posed negligible or negative impact on the granulation, as evidenced by the rupture of smaller aggregates and poor characteristics of AGS. Overall, augmentation of the signaling content via addition of AHLs supernatant from QS strains is an economical and feasible regulation strategy to accelerate granulation and sustain long-term structural stability.
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Affiliation(s)
- Bing Zhang
- School of Environment, Harbin Institute of Technology, Harbin, 150090, China; Department of Civil Engineering, University of Calgary, Calgary, T2N 1N4, Canada
| | - Wei Li
- School of Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Yuan Guo
- School of Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Zhiqiang Zhang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Wenxin Shi
- School of Environment and Ecology, Chongqing University, Chongqing, 400030, China.
| | - Fuyi Cui
- School of Environment and Ecology, Chongqing University, Chongqing, 400030, China.
| | - Piet N L Lens
- UNESCO-IHE Institute for Water Education, Westvest 7, 2601 DA, Delft, the Netherlands
| | - Joo Hwa Tay
- Department of Civil Engineering, University of Calgary, Calgary, T2N 1N4, Canada
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22
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Wang L, Zhan H, Wang Q, Wu G, Cui D. Enhanced aerobic granulation by inoculating dewatered activated sludge under short settling time in a sequencing batch reactor. BIORESOURCE TECHNOLOGY 2019; 286:121386. [PMID: 31078075 DOI: 10.1016/j.biortech.2019.121386] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 04/24/2019] [Accepted: 04/27/2019] [Indexed: 05/06/2023]
Abstract
The effect of dewatered activated sludge on aerobic granulation was investigated in a sequencing batch reactor (SBR) under short settling time. The results showed that dewatered sludge accelerated aerobic granulation and the granulation was completed within 5 days. On day 5, the aerobic granules were regular, compact, fast-settling and high granular strength and possessed excellent removal performance of carbon and nitrogen. The change trend of extracellular polymeric substances (EPS) was basically consistent with granular strength and granulation rate, indicating that EPS in granules played a vital function for granulation. Microbial community succession was investigated by pyrosequencing. In 5 days, microbial diversity was reduced and certain strains were rapidly enriched in the granules to become dominant species, serving on a crucial role in rapid granulation and pollutant removal as they could secrete excess EPS and possess the excellentability removing carbon and nitrogen pollutants.
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Affiliation(s)
- Lei Wang
- School of Environment Science and Spatial Informatics, China University of Mining and Technology, 221116 Xuzhou, China; School of Civil Engineering, Southwest Jiaotong University, 610031 Chengdu, China
| | - Hanhui Zhan
- School of Environment Science and Spatial Informatics, China University of Mining and Technology, 221116 Xuzhou, China.
| | - Qingqing Wang
- School of Environment Science and Spatial Informatics, China University of Mining and Technology, 221116 Xuzhou, China
| | - Gang Wu
- School of Life Science and Engineering, Southwest Jiaotong University, 610031 Chengdu, China
| | - Dabin Cui
- School of Mechanical Engineering, Southwest Jiaotong University, 610031 Chengdu, China
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23
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Kong Z, Li L, Kato H, Zhang T, Xue Y, Li YY. Dissection and characterization of the prokaryotic community during the long-term operation of a submerged anaerobic membrane bioreactor for the anaerobic treatment of N, N-dimethylformamide-containing wastewater with a co-cultured inoculum. BIORESOURCE TECHNOLOGY 2019; 282:482-493. [PMID: 30897486 DOI: 10.1016/j.biortech.2019.03.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 03/01/2019] [Accepted: 03/04/2019] [Indexed: 06/09/2023]
Abstract
A submerged anaerobic membrane bioreactor (SAnMBR) was operated for the anaerobic treatment of wastewater containing approximately 2000 mg L-1N, N-dimethylformamide (DMF). Inoculated with a co-cultured inoculum, the SAnMBR obtained an excellent DMF removal under a low organic loading rate (OLR) of 3.14-4.16 g COD L-1 d-1. However, the elevation of OLR limited hydrolysis. While the co-cultured inoculum initially contains abundant DMF-hydrolyzing bacteria with potential to hydrolyze DMF into intermediates, such as Paracoccus, Hyphomicrobium, Burkholderia, Catellibacterium, Bacillus and Bradyrhizobium, since these bacteria are facultative anaerobes which survive anaerobically, they kept decaying rather than proliferating, resulting in the weakening of the DMF-hydrolyzing ability. Each re-inoculation of new sludge only temporarily revitalized hydrolysis activity for a short period. Due to the lack of nitrate, these bacteria were unable to proliferate. This suggests that a small dose of nitrate would help to enrich these bacteria and establish a stable DMF-degrading consortium.
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Affiliation(s)
- Zhe Kong
- Laboratory of Environmental Protection Engineering, Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, 6-6-06 Aza-Aoba, Aramaki, Aoba Ward, Sendai, Miyagi 980-8579, Japan
| | - Lu Li
- Laboratory of Environmental Protection Engineering, Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, 6-6-06 Aza-Aoba, Aramaki, Aoba Ward, Sendai, Miyagi 980-8579, Japan
| | - Hiroyuki Kato
- The Japan Institute of Wastewater Engineering and Technology, Suido-Cho Bld 7F, 3-1 Suido-Cho, Shinjuku Ward, Tokyo 162-0811, Japan
| | - Tao Zhang
- Laboratory of Environmental Protection Engineering, Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, 6-6-06 Aza-Aoba, Aramaki, Aoba Ward, Sendai, Miyagi 980-8579, Japan
| | - Yi Xue
- Graduate School of Environmental Studies, Tohoku University, 6-6-06 Aza-Aoba, Aramaki, Aoba Ward, Sendai, Miyagi 980-8579, Japan
| | - Yu-You Li
- Laboratory of Environmental Protection Engineering, Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, 6-6-06 Aza-Aoba, Aramaki, Aoba Ward, Sendai, Miyagi 980-8579, Japan; Graduate School of Environmental Studies, Tohoku University, 6-6-06 Aza-Aoba, Aramaki, Aoba Ward, Sendai, Miyagi 980-8579, Japan.
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24
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Liébana R, Modin O, Persson F, Szabó E, Hermansson M, Wilén BM. Combined Deterministic and Stochastic Processes Control Microbial Succession in Replicate Granular Biofilm Reactors. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:4912-4921. [PMID: 30969774 DOI: 10.1021/acs.est.8b06669] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Granular sludge is an efficient and compact biofilm process for wastewater treatment. However, the ecological factors involved in microbial community assembly during the granular biofilm formation are poorly understood, and little is known about the reproducibility of the process. Here, three replicate bioreactors were used to investigate microbial succession during the formation of granular biofilms. We identified three successional phases. During the initial phase, the successional turnover was high and α-diversity decreased as a result of the selection of taxa adapted to grow on acetate and form aggregates. Despite these dynamic changes, the microbial communities in the replicate reactors were similar. The second successional phase occurred when the settling time was rapidly decreased to selectively retain granules in the reactors. The influence of stochasticity on succession increased and new niches were created as granules emerged, resulting in temporarily increased α-diversity. The third successional phase occurred when the settling time was kept stable and granules dominated the biomass. Turnover was low, and selection resulted in the same abundant taxa in the reactors, but drift, which mostly affected low-abundant community members, caused the community in one reactor to diverge from the other two. Even so, performance was stable and similar between reactors.
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Affiliation(s)
- Raquel Liébana
- Division of Water Environment Technology, Department of Architecture and Civil Engineering , Chalmers University of Technology , SE-412 96 Gothenburg , Sweden
| | - Oskar Modin
- Division of Water Environment Technology, Department of Architecture and Civil Engineering , Chalmers University of Technology , SE-412 96 Gothenburg , Sweden
| | - Frank Persson
- Division of Water Environment Technology, Department of Architecture and Civil Engineering , Chalmers University of Technology , SE-412 96 Gothenburg , Sweden
| | - Enikö Szabó
- Division of Water Environment Technology, Department of Architecture and Civil Engineering , Chalmers University of Technology , SE-412 96 Gothenburg , Sweden
| | - Malte Hermansson
- Department of Chemistry and Molecular Biology , University of Gothenburg , SE405 30 Gothenburg , Sweden
| | - Britt-Marie Wilén
- Division of Water Environment Technology, Department of Architecture and Civil Engineering , Chalmers University of Technology , SE-412 96 Gothenburg , Sweden
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25
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Zhang F, Shao J, Yang H, Guo D, Chen Z, Zhang S, Chen H. Effects of biomass pyrolysis derived wood vinegar on microbial activity and communities of activated sludge. BIORESOURCE TECHNOLOGY 2019; 279:252-261. [PMID: 30735935 DOI: 10.1016/j.biortech.2019.01.133] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 01/25/2019] [Accepted: 01/28/2019] [Indexed: 05/14/2023]
Abstract
The effects of wood vinegar (WVG) on microbial activity and communities of activated sludge were investigated in a sequencing batch reactor (SBR) process. Results showed that the optimal WVG concentration was 4 μL/L when the pollutants removal efficiency and microbial activity were promoted by a WVG dilution factor of 1000. WVG could reduce the increase in microbial species richness, which led to a more notable variety of microbial species diversity. The enhanced microbial activity and communities were addressed to the promotion of 7 main classes of microbes in Proteobacteria, Bacteroidetes, Acidobacteria, and Nitrospirae phyla. The growth of ammonia-oxidizing bacteria (AOB), nitrite-oxidizing bacteria (NOB), and main genera of denitrifying bacteria (DNB), phosphorus-accumulating organisms (PAOs), and glycogen-accumulating organisms (GAOs) could be promoted by WVG, which improved the sewage treatment effectiveness in a SBR.
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Affiliation(s)
- Fang Zhang
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Jingai Shao
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; Department of New Energy Science and Technology, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Haiping Yang
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Dabin Guo
- School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zhihua Chen
- School of Environment, Henan Normal University, No. 46, Jianshe Road, Xinxiang 453007, Henan, China
| | - Shihong Zhang
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Hanping Chen
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; Department of New Energy Science and Technology, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
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26
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Yin Y, Sun J, Liu F, Wang L. Effect of nitrogen deficiency on the stability of aerobic granular sludge. BIORESOURCE TECHNOLOGY 2019; 275:307-313. [PMID: 30594841 DOI: 10.1016/j.biortech.2018.12.069] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 12/16/2018] [Accepted: 12/20/2018] [Indexed: 06/09/2023]
Abstract
To assess the stability of aerobic granular sludge (AGS) under nitrogen deficiency conditions, three sequence batch reactors were operated with chemical oxygen demand (COD) to nitrogen (N) ratios of 100/5, 100/2.5, and 100/2, while COD concentration was kept consistent. AGS variations in its physicochemical characteristics, microbial community, and treatment performance were investigated. The results indicated that good treatment performance and stable AGS were achieved under nitrogen deficiency. Extracellular polymeric substances (EPS) regulating mechanism preserved AGS stability under nitrogen deficiency, especially through increased secretion of polysaccharide. In addition, members of the Anaerolineaceae were the major filamentous bacteria, which are strictly anaerobic organism, providing a possible explanation to the lack of filamentous bacteria outgrowth under N deficient condition. Insights from this study could help lower chemical costs in AGS applications for specific industrial wastewater treatments.
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Affiliation(s)
- Yunjun Yin
- School of Environment, MOE Key Laboratory of Water and Sediment Sciences/State Key Lab of Water Environment Simulation, Beijing Normal University, Beijing 100875, China.
| | - Jian Sun
- School of Civil and Architecture Engineering, Xi'an Technological University, Xi'an 710021, China
| | - Fengyuan Liu
- School of Environment, MOE Key Laboratory of Water and Sediment Sciences/State Key Lab of Water Environment Simulation, Beijing Normal University, Beijing 100875, China
| | - Lu Wang
- Development Research Center of the Ministry of Water Resources of P.R. China, Beijing 100038, China
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27
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Wilén BM, Liébana R, Persson F, Modin O, Hermansson M. The mechanisms of granulation of activated sludge in wastewater treatment, its optimization, and impact on effluent quality. Appl Microbiol Biotechnol 2018; 102:5005-5020. [PMID: 29705957 PMCID: PMC5960003 DOI: 10.1007/s00253-018-8990-9] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 04/04/2018] [Accepted: 04/05/2018] [Indexed: 12/14/2022]
Abstract
Granular activated sludge has gained increasing interest due to its potential in treating wastewater in a compact and efficient way. It is well-established that activated sludge can form granules under certain environmental conditions such as batch-wise operation with feast-famine feeding, high hydrodynamic shear forces, and short settling time which select for dense microbial aggregates. Aerobic granules with stable structure and functionality have been obtained with a range of different wastewaters seeded with different sources of sludge at different operational conditions, but the microbial communities developed differed substantially. In spite of this, granule instability occurs. In this review, the available literature on the mechanisms involved in granulation and how it affects the effluent quality is assessed with special attention given to the microbial interactions involved. To be able to optimize the process further, more knowledge is needed regarding the influence of microbial communities and their metabolism on granule stability and functionality. Studies performed at conditions similar to full-scale such as fluctuation in organic loading rate, hydrodynamic conditions, temperature, incoming particles, and feed water microorganisms need further investigations.
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Affiliation(s)
- Britt-Marie Wilén
- Division of Water Environment Technology, Department of Architecture and Civil and Engineering, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden.
| | - Raquel Liébana
- Division of Water Environment Technology, Department of Architecture and Civil and Engineering, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
| | - Frank Persson
- Division of Water Environment Technology, Department of Architecture and Civil and Engineering, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
| | - Oskar Modin
- Division of Water Environment Technology, Department of Architecture and Civil and Engineering, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
| | - Malte Hermansson
- Department of Chemistry and Molecular Biology, University of Gothenburg, SE-405 30, Gothenburg, Sweden
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