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Li X, Li S, Xie P, Chen X, Chu Y, Chang H, Sun J, Li Q, Ren N, Ho SH. Advanced wastewater treatment with microalgae-indigenous bacterial interactions. ENVIRONMENTAL SCIENCE AND ECOTECHNOLOGY 2024; 20:100374. [PMID: 38283868 PMCID: PMC10821166 DOI: 10.1016/j.ese.2023.100374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 12/13/2023] [Accepted: 12/17/2023] [Indexed: 01/30/2024]
Abstract
Microalgal-indigenous bacterial wastewater treatment (MBWT) emerges as a promising approach for the concurrent removal of nitrogen (N) and phosphorus (P). Despite its potential, the prevalent use of MBWT in batch systems limits its broader application. Furthermore, the success of MBWT critically depends on the stable self-adaptation and synergistic interactions between microalgae and indigenous bacteria, yet the underlying biological mechanisms are not fully understood. Here we explore the viability and microbial dynamics of a continuous flow microalgae-indigenous bacteria advanced wastewater treatment system (CFMBAWTS) in processing actual secondary effluent, with a focus on varying hydraulic retention times (HRTs). The research highlights a stable, mutually beneficial relationship between indigenous bacteria and microalgae. Microalgae and indigenous bacteria can create an optimal environment for each other by providing essential cofactors (like iron, vitamins, and indole-3-acetic acid), oxygen, dissolved organic matter, and tryptophan. This collaboration leads to effective microbial growth, enhanced N and P removal, and energy generation. The study also uncovers crucial metabolic pathways, functional genes, and patterns of microbial succession. Significantly, the effluent NH4+-N and P levels complied with the Chinese national Class-II, Class-V, Class-IA, and Class-IB wastewater discharge standards when the HRT was reduced from 15 to 6 h. Optimal results, including the highest rates of CO2 fixation (1.23 g L-1), total energy yield (32.35 kJ L-1), and the maximal lipid (33.91%) and carbohydrate (41.91%) content, were observed at an HRT of 15 h. Overall, this study not only confirms the feasibility of CFMBAWTS but also lays a crucial foundation for enhancing our understanding of this technology and propelling its practical application in wastewater treatment plants.
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Affiliation(s)
- Xue Li
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Shengnan Li
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Peng Xie
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Xi Chen
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Yuhao Chu
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Haixing Chang
- College of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing, 400054, PR China
| | - Jian Sun
- Central Southern China Municipal Engineering Design and Research Institute Co., Ltd, Wuhan, 430010, PR China
| | - Qing Li
- Central Southern China Municipal Engineering Design and Research Institute Co., Ltd, Wuhan, 430010, PR China
| | - Nanqi Ren
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Shih-Hsin Ho
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China
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Fan J, Yuan W, Zhang X, Ji B, Du X. Oxygen affinity and light intensity induced robust phosphorus removal and fragile ammonia removal in a non-aerated bacteria-algae system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:169013. [PMID: 38040345 DOI: 10.1016/j.scitotenv.2023.169013] [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: 09/01/2023] [Revised: 11/28/2023] [Accepted: 11/28/2023] [Indexed: 12/03/2023]
Abstract
Non-aerated bacteria-algae system gaining O2 through photosynthesis presents an alternative for costly mechanical aeration. This study investigated oxygen supply and performance of nutrients removal at low and high light intensity (LL and HL). The results showed that P removal was high and robust (LL 97 ± 1.8 %, HL 95 % ± 2.9 %), while NH4+-N removal fluctuated dramatically (LL 66 ± 14.7 %, HL 84 ± 8.6 %). Oxygen generated at illumination of 200 μmol m-2 s-1, 6 h was sufficient to sustain aerobic phase for 2.25 g/L MLSS. However, O2 produced by algae was preferentially captured in the order of heterotrophic bacteria (HB), ammonia oxidizing bacteria (AOB), nitrite oxidizing bacteria (NOB). Oxygen affinity coupled with light intensity led to NOB suppression with stable nitrite accumulation ratio of 57 %. Free nitrous acid (FNA) and light stimulated the abundance of denitrifying polyphosphate accumulating organism (DPAO) of Flavobacterium, but with declined P-accumulating metabolism (PAM) of P release, P/C, K/P and Mg/P ratios. Flavobacterium and cyanobacteria Leptolyngbya, along with biologically induced CaP in extracellular polymeric substances was the key to robust P removal. AOB of Ellin6067 and DPAO of Flavobacteria offer a promising scenario for partial nitrification-denitrifying phosphorus removal.
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Affiliation(s)
- Jie Fan
- College of Urban Construction, Wuhan University of Science and Technology, Wuhan 430065, China.
| | - Wu Yuan
- College of Urban Construction, Wuhan University of Science and Technology, Wuhan 430065, China
| | - Xujie Zhang
- College of Urban Construction, Wuhan University of Science and Technology, Wuhan 430065, China
| | - Bin Ji
- College of Urban Construction, Wuhan University of Science and Technology, Wuhan 430065, China
| | - Xingyu Du
- College of Urban Construction, Wuhan University of Science and Technology, Wuhan 430065, China
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Chen B, Shen Y, Zhang X, Ji B. Influence mechanism of sludge bed position on microalgal-bacterial granular sludge process. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 907:168118. [PMID: 37884157 DOI: 10.1016/j.scitotenv.2023.168118] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 10/16/2023] [Accepted: 10/23/2023] [Indexed: 10/28/2023]
Abstract
Sludge bed position in the reactor is one of the key parameters for microalgal-bacterial granular sludge (MBGS) process, which lacks of study. To fill this gap, this study investigated the influence of sludge bed position on MBGS. The sludge bed located closer to the bottom of the bioreactor demonstrated the optimal pollutant removal performance due to a close synergistic effect between microalgae and bacteria, resulting in the high growth rate as well as agglomeration rate of MBGS. Specifically, organics and ammonia removals were closely related to the sludge bed position. For the bottom bed position, the removals of organic matter, ammonia, and phosphate were 75.1 %, 73.1 %, and 82.5 %, whereas for the top bed position, they were only 13.2 %, 9.6 %, and 68.9 %, respectively. Additionally, a significant correlation between the position of the sludge bed and the relative abundance of Rotifera (R2 = 0.931) and Chlorophyta (R2 = 0.733) was observed, while the microbial communities at the lower sludge bed positions underwent rapider succession. It can be inferred that that a sludge bed located closer to the bottom of the bioreactor ensures that the light source and substrate matrix are transmitted in the same direction, thereby resulting in a close synergistic effect between microalgae and bacteria for achieving the excellent performance of MBGS. These results can provide basis knowledge for engineering application of MBGS process.
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Affiliation(s)
- Bingheng Chen
- Department of Water and Wastewater Engineering, School of Urban Construction, Wuhan University of Science and Technology, Wuhan 430065, China
| | - Yao Shen
- Department of Water and Wastewater Engineering, School of Urban Construction, Wuhan University of Science and Technology, Wuhan 430065, China
| | - Xiaoyuan Zhang
- Engineering Laboratory of Low-Carbon Unconventional Water Resources Utilization and Water Quality Assurance, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
| | - Bin Ji
- Department of Water and Wastewater Engineering, School of Urban Construction, Wuhan University of Science and Technology, Wuhan 430065, China; Hubei Provincial Engineering Research Center of Urban Regeneration, Wuhan University of Science and Technology, Wuhan 430065, China.
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4
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Zhang JT, Wang JX, Liu Y, Zhang Y, Wang JH, Chi ZY, Kong FT. Microalgal-bacterial biofilms for wastewater treatment: Operations, performances, mechanisms, and uncertainties. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 907:167974. [PMID: 37884155 DOI: 10.1016/j.scitotenv.2023.167974] [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: 07/18/2023] [Revised: 09/28/2023] [Accepted: 10/18/2023] [Indexed: 10/28/2023]
Abstract
Microalgal-bacterial biofilms have been increasingly considered of great potential in wastewater treatment due to the advantages of microalgal-bacterial synergistic pollutants removal/recovery, CO2 sequestration, and cost-effective biomass-water separation. However, such advantages may vary widely among different types of microalgal-bacterial biofilms, as the biofilms could be formed on different shapes and structures of attachment substratum, generating "false hope" for certain systems in large-scale wastewater treatment if the operating conditions and pollutants removal properties are evaluated based on the general term "microalgal-bacterial biofilm". This study, therefore, classified microalgal-bacterial biofilms into biofilms formed on 2D substratum, biofilms formed on 3D substratum, and biofilms formed without substratum (i.e. microalgal-bacterial granular sludge, MBGS). Biofilms formed on 2D substratum display higher microalgae fractions and nutrients removal efficiencies, while the adopted long hydraulic retention times were unacceptable for large-scale wastewater treatment. MBGS are featured with much lower microalgae fractions, most efficient pollutants removal, and acceptable retention times for realistic application, yet the feasibility of using natural sunlight should be further explored. 3D substratum systems display wide variations in operating conditions and pollutants removal properties because of diversified substratum shapes and structures. 2D and 3D substratum biofilms share more common in eukaryotic and prokaryotic microbial community structures, while MGBS biofilms are more enriched with microorganisms favoring EPS production, biofilm formation, and denitrification. The specific roles of stratified extracellular polymeric substances (EPS) in nutrients adsorption and condensation still require in-depth exploration. Nutrients removal uncertainties caused by microalgal-bacterial synergy decoupling under insufficient illumination, limited microbial community control, and possible greenhouse gas emission exacerbation arising from microalgal N2O generation were also indicated. This review is helpful for revealing the true potential of applying various microalgal-bacterial biofilms in large-scale wastewater treatment, and will provoke some insights on the challenges to the ideal state of synergistic pollutants reclamation and carbon neutrality via microalgal-bacterial interactions.
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Affiliation(s)
- Jing-Tian Zhang
- School of Bioengineering, Dalian University of Technology, Dalian 116024, PR China
| | - Jian-Xia Wang
- School of Bioengineering, Dalian University of Technology, Dalian 116024, PR China
| | - Yang Liu
- School of Bioengineering, Dalian University of Technology, Dalian 116024, PR China
| | - Ying Zhang
- School of Bioengineering, Dalian University of Technology, Dalian 116024, PR China
| | - Jing-Han Wang
- School of Bioengineering, Dalian University of Technology, Dalian 116024, PR China; Key Laboratory of Environment Controlled Aquaculture, Dalian Ocean University, Dalian 116023, PR China.
| | - Zhan-You Chi
- School of Bioengineering, Dalian University of Technology, Dalian 116024, PR China
| | - Fan-Tao Kong
- School of Bioengineering, Dalian University of Technology, Dalian 116024, PR China
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Shen Y, Chen B, Wang S, Li A, Ji B. Necessity of stirring for outdoor microalgal-bacterial granular sludge process. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 345:118816. [PMID: 37598492 DOI: 10.1016/j.jenvman.2023.118816] [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: 06/15/2023] [Revised: 08/02/2023] [Accepted: 08/12/2023] [Indexed: 08/22/2023]
Abstract
As a green process, microalgal-bacterial granular sludge (MBGS) process shows talents in achieving pollutant removal, resource recovery and carbon neutralization. However, when it comes to application, the adequate mixing of MBGS and substrate should be adopted theoretically. Therefore, this study devoted to address the necessity of stirring for MBGS in municipal wastewater treatment. Outdoor performances showed that stirring significantly enhanced both of the photosynthetic efficiency and biomass productivity of MBGS with almost 2-fold increase as compared to non-stirred MBGS, while the average pore size and microalgae-to-bacteria ratio also increased. Consequently, stirring acted as a pivotal role in accelerating pollutants removal, with removals of organics (89.89% COD) and nutrients (99.22% NH4+-N, 92.15% PO43--P) reaching peak levels at 2 h and 6 h, respectively, while removals of organics (87.50% COD) and nutrients (86.11% NH4+-N, 86.76% PO43--P) removal peaked at 8 h for non-stirred MBGS. The improved granule characteristics and microbial compositions due to the stirring were found to be favorable for MBGS to adapting to the changeable weather. Based on the above results, the possible underlying mechanisms of stirring for improving MBGS were illustrated. Overall, stirring positively impacted the photosynthetic efficiency, biomass productivity, pollutant removal and microbial structure for MBGS. This study gains knowledge on stirred MBGS process under outdoor conditions for its future practical application.
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Affiliation(s)
- Yao Shen
- Department of Water and Wastewater Engineering, Wuhan University of Science and Technology, Wuhan, 430065, China; Hubei Provincial Engineering Research Center of Urban Regeneration, Wuhan University of Science and Technology, Wuhan, 430065, China
| | - Bingheng Chen
- Department of Water and Wastewater Engineering, Wuhan University of Science and Technology, Wuhan, 430065, China; Hubei Provincial Engineering Research Center of Urban Regeneration, Wuhan University of Science and Technology, Wuhan, 430065, China
| | - Shuo Wang
- Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Civil Engineering, Jiangnan University, Wuxi, 214122, 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
| | - Bin Ji
- Department of Water and Wastewater Engineering, Wuhan University of Science and Technology, Wuhan, 430065, China; Hubei Provincial Engineering Research Center of Urban Regeneration, Wuhan University of Science and Technology, Wuhan, 430065, China.
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Kadri MS, Singhania RR, Haldar D, Patel AK, Bhatia SK, Saratale G, Parameswaran B, Chang JS. Advances in Algomics technology: Application in wastewater treatment and biofuel production. BIORESOURCE TECHNOLOGY 2023; 387:129636. [PMID: 37544548 DOI: 10.1016/j.biortech.2023.129636] [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: 06/08/2023] [Revised: 07/31/2023] [Accepted: 08/03/2023] [Indexed: 08/08/2023]
Abstract
Advanced sustainable bioremediation is gaining importance with rising global pollution. This review examines microalgae's potential for sustainable bioremediation and process enhancement using multi-omics approaches. Recently, microalgae-bacterial consortia have emerged for synergistic nutrient removal, allowing complex metabolite exchanges. Advanced bioremediation requires effective consortium design or pure culture based on the treatment stage and specific roles. The strain potential must be screened using modern omics approaches aligning wastewater composition. The review highlights crucial research gaps in microalgal bioremediation. It discusses multi-omics advantages for understanding microalgal fitness concerning wastewater composition and facilitating the design of microalgal consortia based on bioremediation skills. Metagenomics enables strain identification, thereby monitoring microbial dynamics during the treatment process. Transcriptomics and metabolomics encourage the algal cell response toward nutrients and pollutants in wastewater. Multi-omics role is also summarized for product enhancement to make algal treatment sustainable and fit for sustainable development goals and growing circular bioeconomy scenario.
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Affiliation(s)
- Mohammad Sibtain Kadri
- Department of Marine Biotechnology and Resources, National Sun Yat-Sen University, Kaohsiung City 804201, Taiwan
| | - Reeta Rani Singhania
- Institute of Aquatic Science and Technology, National Kaohsiung University of Science and Technology, Kaohsiung City 81157, Taiwan; Centre for Energy and Environmental Sustainability, Lucknow 226 029, Uttar Pradesh, India
| | - Dibyajyoti Haldar
- Department of Biotechnology, Karunya Institute of Technology and Sciences, Coimbatore 641114, India
| | - Anil Kumar Patel
- Institute of Aquatic Science and Technology, National Kaohsiung University of Science and Technology, Kaohsiung City 81157, Taiwan; Centre for Energy and Environmental Sustainability, Lucknow 226 029, Uttar Pradesh, India.
| | - Shashi Kant Bhatia
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 805029, Republic of Korea
| | - Ganesh Saratale
- Department of Food Science and Biotechnology, Dongguk University-Seoul, Ilsandong-gu, Goyang-si 10326, Republic of Korea
| | - Binod Parameswaran
- Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST), Trivandrum 695 019, Kerala, India
| | - Jo-Shu Chang
- Department of Chemical Engineering, National Cheng Kung University, Taiwan; Department of Chemical and Materials Engineering, Tunghai University, Taiwan; Research Center for Smart Sustainable Circular Economy, Tunghai University, Taiwan.
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7
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Paulenco A, Vintila ACN, Vlaicu A, Ciltea-Udrescu M, Galan AM. Nannochloris sp. Microalgae Strain for Treatment of Dairy Wastewaters. Microorganisms 2023; 11:1469. [PMID: 37374971 DOI: 10.3390/microorganisms11061469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 05/25/2023] [Accepted: 05/28/2023] [Indexed: 06/29/2023] Open
Abstract
This paper focuses on a process for dairy wastewater treatment by mixotrophic cultivation of microalgae Nannochloris sp., using cheese whey obtained as a side flow from cheese production as an organic carbon source. The microalgae samples were prepared by adding to the standard growth medium increasing amounts of cheese whey, calculated to ensure a lactose concentration between 0 and 10 g/L. The samples were incubated at a constant temperature of 28 °C and 175 rpm stirring speed for a total time of seven days. Two LED (Light Emitting Diode) illumination schemes were applied in order to assess the effect of this parameter on microalgae development and bioactive compound accumulation: continuous illumination (light stress) versus alternative cycles of 12 h light-12 h dark (day-night cycle). The growth medium was analyzed before and after microalgae cultivation in order to determine the reduction of carbon, nitrogen, and phosphorus. The results obtained for this process, after a seven-day cultivation period, were as follows: reduction of 99-100% of lactose from the growth medium, up to 96% reduction in chemical oxygen demand, up to 91% reduction in nitrogen content, and up to 70% reduction in phosphorus content.
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Affiliation(s)
- Anca Paulenco
- National Institute for Research & Development in Chemistry and Petrochemistry-ICECHIM, 202 Spl. Independentei, 060021 Bucharest, Romania
| | - Alin Cristian Nicolae Vintila
- National Institute for Research & Development in Chemistry and Petrochemistry-ICECHIM, 202 Spl. Independentei, 060021 Bucharest, Romania
- Faculty of Chemical Engineering and Biotechnologies, University Politehnica of Bucharest, 1-7 Polizu Street, 011061 Bucharest, Romania
| | - Alexandru Vlaicu
- National Institute for Research & Development in Chemistry and Petrochemistry-ICECHIM, 202 Spl. Independentei, 060021 Bucharest, Romania
| | - Mihaela Ciltea-Udrescu
- National Institute for Research & Development in Chemistry and Petrochemistry-ICECHIM, 202 Spl. Independentei, 060021 Bucharest, Romania
- Faculty of Chemical Engineering and Biotechnologies, University Politehnica of Bucharest, 1-7 Polizu Street, 011061 Bucharest, Romania
| | - Ana-Maria Galan
- National Institute for Research & Development in Chemistry and Petrochemistry-ICECHIM, 202 Spl. Independentei, 060021 Bucharest, Romania
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Trebuch LM, Schoofs K, Vaessen SMF, Neu TR, Janssen M, Wijffels RH, Vet LEM, Fernandes TV. N 2 -fixation can sustain wastewater treatment performance of photogranules under nitrogen-limiting conditions. Biotechnol Bioeng 2023; 120:1303-1315. [PMID: 36779371 DOI: 10.1002/bit.28349] [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: 08/30/2022] [Revised: 12/23/2022] [Accepted: 02/09/2023] [Indexed: 02/14/2023]
Abstract
Wastewater characteristics can vary significantly, and in some municipal wastewaters the N:P ratio is as low as 5 resulting in nitrogen-limiting conditions. In this study, the microbial community, function, and morphology of photogranules under nitrogen-replete (N+) and limiting (N-) conditions was assessed in sequencing batch reactors. Photogranules under N- condition were nitrogen deprived 2/3 of a batch cycle duration. Surprisingly, this nitrogen limitation had no adverse effect on biomass productivity. Moreover, phosphorus and chemical oxygen demand removal were similar to their removal under N+ conditions. Although performance was similar, the difference in granule morphology was obvious. While N+ photogranules were dense and structurally confined, N- photogranules showed loose structures with occasional voids. Microbial community analysis revealed high abundance of cyanobacteria capable of N2 -fixation. These were higher at N- (38%) than N+ (29%) treatments, showing that photogranules could adjust and maintain treatment performance and high biomass productivity by means of N2 -fixation.
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Affiliation(s)
- Lukas M Trebuch
- Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands.,Bioprocess Engineering, AlgaePARC Wageningen University, Wageningen, The Netherlands
| | - Kobe Schoofs
- Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands.,Bioprocess Engineering, AlgaePARC Wageningen University, Wageningen, The Netherlands
| | - Stijn M F Vaessen
- Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands.,Bioprocess Engineering, AlgaePARC Wageningen University, Wageningen, The Netherlands
| | - Thomas R Neu
- Microbiology of Interfaces, Department River Ecology, Helmholtz Centre for Environmental Research - UFZ, Magdeburg, Germany
| | - Marcel Janssen
- Bioprocess Engineering, AlgaePARC Wageningen University, Wageningen, The Netherlands
| | - René H Wijffels
- Bioprocess Engineering, AlgaePARC Wageningen University, Wageningen, The Netherlands.,Faculty of Biosciences and Aquaculture, Nord University, Bodø, Norway
| | - Louise E M Vet
- Department of Terrestrial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands
| | - Tânia V Fernandes
- Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands
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Vincent F, Rao TS, Kumar R, Nancharaiah YV. Exploring the effects of organic loading rate and domestic wastewater treatment by algal-bacterial granules under natural daylight conditions. WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2023; 95:e10831. [PMID: 36617440 DOI: 10.1002/wer.10831] [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: 07/13/2022] [Revised: 12/04/2022] [Accepted: 12/13/2022] [Indexed: 06/17/2023]
Abstract
Algal-bacterial granules or phototrophic granules (PGs) comprising phototrophic microorganisms and bacteria are explored in wastewater treatment for achieving both environmental and economic sustainability. This study describes development of PGs and their use in biological treatment of synthetic and real domestic wastewater (sewage) under natural daylight conditions and low organic loading rate (OLR). Development of PGs was sequentially recorded in a photobioreactor operated in photo-sequencing batch reactor (photo-SBR) mode at a low OLR of 1 kgCOD.m-3 .day-1 and the developed PGs was evaluated for treating synthetic wastewater and real municipal wastewater with 0.14 kg COD m-3 .day-1 . PGs formed in the photo-sequential batch reactor (SBR) were compact and dense and exhibited excellent settling properties. The removal efficiencies were determined to be up to 95%, 93%, 97%, 72%, and 88% for turbidity, COD, TOC, NH4 + -N, and NO2 - -N/NO3 - -N, respectively. Additionally, a reduction in total viable bacterial counts and fecal coliform bacteria up to 1.7 × 103 and 7.8 × 102 cfu.mL-1 , respectively, during treatment of real municipal wastewater was achieved. This study demonstrated cultivation of algal-bacterial granules or PGs and their application for treating real municipal wastewater under natural daylight and tropical climate conditions. Further studies are needed on understanding interactions among phototrophic, autotrophic, and heterotrophic microorganisms of complex algal-bacterial consortium for emerging applications in bioremediation and wastewater treatment. PRACTITIONER POINTS: Phototrophic granules (PGs) were cultivated from algal consortium and activated sludge inoculum in photo sequencing batch reactors. Granular photobioreactor was operated at low OLR of 1 kgCOD.m3 .day-1 for developing well-settling algal-bacterial granules. PGs were stable and showed efficient biological treatment of synthetic wastewater and real sewage. Removals for turbidity, pathogens, and ammonium were at 95%, 3-log, and 72%, respectively, from real sewage.
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Affiliation(s)
- Francis Vincent
- Biofouling and Biofilm Processes Section, WSCD, Chemistry Group, Bhabha Atomic Research Centre, Kalpakkam, India
| | - Toleti Subba Rao
- Biofouling and Biofilm Processes Section, WSCD, Chemistry Group, Bhabha Atomic Research Centre, Kalpakkam, India
| | - Rajesh Kumar
- Biofouling and Biofilm Processes Section, WSCD, Chemistry Group, Bhabha Atomic Research Centre, Kalpakkam, India
- Homi Bhabha National Institute, Mumbai, India
| | - Yarlagadda Venkata Nancharaiah
- Biofouling and Biofilm Processes Section, WSCD, Chemistry Group, Bhabha Atomic Research Centre, Kalpakkam, India
- Homi Bhabha National Institute, Mumbai, India
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10
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Li J, Ou R, Liao H, Ma J, Sun L, Jin Q, He D, Wang Q. Natural lighting enhancing the algae proliferation and nitrogen removal in membrane-aerated bacterial-algal biofilm reactor. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 851:158063. [PMID: 35981577 DOI: 10.1016/j.scitotenv.2022.158063] [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: 06/10/2022] [Revised: 08/04/2022] [Accepted: 08/12/2022] [Indexed: 06/15/2023]
Abstract
Membrane-aerated bacterial-algal biofilm reactor (MABAR) is an emerging and novel technology in recent years, which has been attracting increasing attention due to its cost-effectiveness and superior removal performance of pollutants by versatile removal pathways in symbiotic bacterial-algal biofilm. However, the wider application of MABAR is hindered by the dilemma of insufficient algae biomass. In this study, an MABAR under natural sunlight was developed and operated for 160 d to access the feasibility of enhancing algae proliferation by natural lighting. Results showed that the MABAR with natural sunlight (nMABAR) demonstrated better performance of pollutants removal. High removal efficiencies of organic matter and NH4-N in nMABAR were 90 % and 92 %, respectively. In particular, the removal efficiency of TN in nMABAR, under less aeration, was up to 80 %, which was 15 % higher than the control reactor. The Chlorophyll-a content indicated that natural sunlight facilitated to algae growth in MABAR, and algae assimilation might be the dominant contributor to NH4-N removal. Moreover, there were microbial shifts in bacterial-algal biofilm in a response to the natural lighting, the nMABAR uniquely possessed a bacterial phylotype termed Thiocapsa, which could play an important role in bacterial nitrification. Algal phylotype Chlorophyceae significantly contributed to pollutants removal and synergistic relationship with bacteria. In addition, the superb performance of nMABAR under less aeration condition suggested that abundant algae were capable of supplying enough O2 for the system. These results provided insight into the natural lighting on algae-bacteria synergistic growth and cost-effective operation strategy for MABAR.
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Affiliation(s)
- Jibin Li
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Rui Ou
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Huaiyu Liao
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Jinxing Ma
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, PR China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, PR China.
| | - Li Sun
- Tianjin Key Laboratory of Clean Energy and Pollution Control, School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin 300401, PR China.
| | - Qinghai Jin
- Shenzhen Pangu Environmental Protection Technology Co. Ltd, Shenzhen 518055, PR China
| | - Di He
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, PR China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, PR China.
| | - Qilin Wang
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Ultimo, NSW 2007, Australia.
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11
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Zhou Y, Zhou Y, Chen S, Guo N, Xiang P, Lin S, Bai Y, Hu X, Zhang Z. Evaluating the role of algae in algal-bacterial granular sludge: Nutrient removal, microbial community and granular characteristics. BIORESOURCE TECHNOLOGY 2022; 365:128165. [PMID: 36283664 DOI: 10.1016/j.biortech.2022.128165] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 10/13/2022] [Accepted: 10/15/2022] [Indexed: 06/16/2023]
Abstract
Algal-bacterial granular sludge (ABGS) and bacterial granular sludge (BGS, control group) were operated over 240 days to investigate the role of algae in treating synthetic municipal wastewater. The results showed that algae significantly improved the removal efficiency of total nitrogen (TN). The nitrogen removal load of ABGS was 2.6 mg-N/g-VSS/day (22.8 %, light) and 1.1 mg-N/g-VSS/day (9.6 %, dark) higher than that of BGS, respectively, which was attributed to algae enhanced NH3-N removal capacity in the anaerobic stage and increased the utilization efficiency of organics in denitrification. Algae increased the relative abundance of denitrifying bacteria, and ABGS (28.83 %) was higher than BGS (14.28 %). Moreover, the dominant phylum of algae was Chlorophyta (98.39 %), the chlorophyll-a was sustained at 1.28 ± 0.26 mg/g-VSS. Algae significantly increased the content of extracellular polymeric substances (EPS), and the increased polysaccharide came from the tightly bound EPS. This study expands the understanding of the role of algae in ABGS.
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Affiliation(s)
- Yingying Zhou
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China; College of Environment and Ecology, Chongqing University, Chongqing 400045, China
| | - Yuanhang Zhou
- College of Environment and Ecology, Chongqing University, Chongqing 400045, China
| | - Siqin Chen
- College of Environment and Ecology, Chongqing University, Chongqing 400045, China
| | - Niuniu Guo
- College of Environment and Ecology, Chongqing University, Chongqing 400045, China
| | - Ping Xiang
- College of Environment and Ecology, Chongqing University, Chongqing 400045, China
| | - Shutao Lin
- College of Environment and Ecology, Chongqing University, Chongqing 400045, China
| | - Yun Bai
- College of Environment and Ecology, Chongqing University, Chongqing 400045, China
| | - Xueli Hu
- College of Environment and Ecology, Chongqing University, Chongqing 400045, China
| | - Zhi Zhang
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China; College of Environment and Ecology, Chongqing University, Chongqing 400045, China.
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12
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Fan J, Zhang X, Du X, Cai Z. Insights into activated sludge/Chlorella consortia under dark condition compared with light condition. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2022; 86:1915-1926. [PMID: 36315085 DOI: 10.2166/wst.2022.322] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Bacteria-algae consortia in the light bring the benefit of O2 production and CO2 reduction for wastewater treatment, while the bottleneck for application is how it behaves in the dark. In this study, inoculum ratio and sludge retention time (SRT) affected nutrient removal rather than chemical oxygen demand (COD) removal. Dark conditions (with a sludge/Chlorella inoculum ratio of 1:2 at a SRT of 15 d) achieved comparable performance to those of light conditions, due to bacteria contribution and mechanical aeration. Compared with light conditions, the ratio of Chla/Chlb decreased and Caro/(Chla + Chlb) increased to response oxidative stress. In the dark, algae were associated with Nitrosomonas and Dechloromonas. Flavobacterium disassociated with Chlorella in the dark but associated with Chlorella in the light. Moreover, nitritation genes (amo and Hao) and denitrifying gene (narH) were up-regulated, while P metabolism genes (PPX and PPK) were down-regulated. It is proposed to enrich Nitrosomonas in the night and denitrify polyphosphate accumulating organisms (DPAO) in the daytime to establish short-cut nitrification and denitrifying phosphorus removal in practical applications.
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Affiliation(s)
- Jie Fan
- Department of Water and Wastewater Engineering, Wuhan University of Science and Technology, Wuhan 430065, China E-mail: ; State Environmental Protection Key Laboratory of Mineral Metallurgical Resources Utilization and Pollution Control, Wuhan University of Science and Technology, Wuhan 430065, China
| | - Xujie Zhang
- Department of Water and Wastewater Engineering, Wuhan University of Science and Technology, Wuhan 430065, China E-mail:
| | - Xingyu Du
- Department of Water and Wastewater Engineering, Wuhan University of Science and Technology, Wuhan 430065, China E-mail:
| | - Zhenlei Cai
- State Environmental Protection Key Laboratory of Mineral Metallurgical Resources Utilization and Pollution Control, Wuhan University of Science and Technology, Wuhan 430065, China
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13
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Re-cultivation of dry microalgal-bacterial granular sludge. ALGAL RES 2022. [DOI: 10.1016/j.algal.2022.102858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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14
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Zhang X, Lei Z, Liu Y. Microalgal-bacterial granular sludge for municipal wastewater treatment: From concept to practice. BIORESOURCE TECHNOLOGY 2022; 354:127201. [PMID: 35460841 DOI: 10.1016/j.biortech.2022.127201] [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: 02/27/2022] [Revised: 04/17/2022] [Accepted: 04/18/2022] [Indexed: 06/14/2023]
Abstract
Recently, increasing interest has been placed in microalgal-bacterial granular sludge (MBGS) in the journey towards the energy and carbon neutrality of municipal wastewater treatment. Different from aerobic granular sludge, the performance of MBGS is mainly determined by the mutualism and symbiosis between coexisting microalgae and bacteria. It appears from the literature that most of studies on MBGS were conducted at small benchtop scales under controlled conditions with synthetic wastewater. Therefore, this article attempts to look into the major engineering gaps between the knowledge generated from numerous laboratory research works and the large-scale application of MBGS, including massive production of MBGS, type of bioreactor, effect of alternate photo and dark metabolisms on effluent quality, resource recovery from waste MBGS, etc. It is clearly demonstrated that MBGS is still at its infant stage, and more effort is strongly needed to identify the technological bottlenecks of full-scale applications, while providing corresponding engineering solutions.
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Affiliation(s)
- Xiaoyuan Zhang
- Advanced Environmental Biotechnology Centre, Nanyang Environment & Water Research Institute, Nanyang Technological University, Singapore 637141, Singapore.
| | - Zhongfang Lei
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Yu Liu
- School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
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15
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Ji B, Fan S, Liu Y. A continuous-flow non-aerated microalgal-bacterial granular sludge process for aquaculture wastewater treatment under natural day-night conditions. BIORESOURCE TECHNOLOGY 2022; 350:126914. [PMID: 35231593 DOI: 10.1016/j.biortech.2022.126914] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 02/20/2022] [Accepted: 02/23/2022] [Indexed: 06/14/2023]
Abstract
This study developed a continuous-flow non-aerated microalgal-bacterial granular tubular reactor for aquaculture wastewater treatment under natural day-night conditions. Results showed that daytime was favorable for ammonia removal while nighttime for nitrate removal. Over 99% of nitrite-N could be removed over the day-night cycles at a hydraulic retention time of 6 h. However, the phosphorus removal was found to be sensitive to the weather condition, ranging from 35.0% to 96.6%. It was also observed that dissolved oxygen produced by microalgae in daytime was sufficient for creating a 6-h aerobic condition in nighttime for sustaining heterotrophic activity. Chlorella and Leptolyngbya were identified as the most abundant algae related to weather changes. Metagenomics analysis revealed that the high nitrite removal relied mainly on nitrite reduction. These experimental findings offer new insights into the non-aerated microalgal-bacterial granular sludge for environmentally sustainable aquaculture wastewater treatment.
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Affiliation(s)
- Bin Ji
- Department of Water and Wastewater Engineering, Wuhan University of Science and Technology, Wuhan 430065, PR China.
| | - Siqi Fan
- Department of Water and Wastewater Engineering, Wuhan University of Science and Technology, Wuhan 430065, PR China
| | - Yu Liu
- Advanced Environmental Biotechnology Centre, Nanyang Environment & Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
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16
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Candido C, Cardoso LG, Lombardi AT. Bioprospecting and selection of tolerant strains and productive analyses of microalgae grown in vinasse. Braz J Microbiol 2022; 53:845-855. [PMID: 35137357 PMCID: PMC9151925 DOI: 10.1007/s42770-022-00692-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 01/30/2022] [Indexed: 02/01/2023] Open
Abstract
In order to contribute to the biotechnology of microalgae cultivated in vinasse, we carried out the bioprospection of tolerant species and synthesized biomolecules of the total biomass (microalgae and bacteria), recovered from cultures. To use vinasse as a culture medium for the microalgae, waste was centrifuged and used in concentrations from 5 to 50%. Daily cell densities, growth rates, and EC50 values were obtained. After defining the best pair of vinasse concentration/microalgae strain, dry biomass, and composition (proteins and carbohydrates) were determined in 96 h cultures, considering the associated community (bacteria and yeast). The microalgae tested were Chlamydomonas sp., Chlorella sorokiniana, Chlorella vulgaris, Desmodesmus spinosus, Haematococcus pluvialis, Monoraphidium sp., Scenedesmus quadricauda, and Tetraselmis gracilis. The results showed that although the microalgal growth rates in vinasse were similar to controls in BG11, the cells in vinasse had higher biovolumes, dry biomass, and total proteins. The species H. pluvialis, S. quadricauda, and T. gracilis showed the best productivity parameters in vinasse, despite lower growth rates than the other species. Using low concentrations of centrifuged vinasse as a culture medium, only 22% of biological contaminants were present, thus most of the processed biomass was mainly composed of microalgae. Thus, Chlamydomonas sp., D. spinosus, S. quadricauda, and H. pluvialis microalgae have attributes such as resistance and biomolecules that make them candidates for further optimization in production systems, combining the environmental benefits of using waste with the production of biomolecules and/or biomass of commercial interest.
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Affiliation(s)
- Camila Candido
- Programa de Pós-Graduação em Ecologia e Recursos Naturais (PPGERN), Universidade Federal de São Carlos (UFSCar), Rod. Washington Luís km 235, São Paulo, São Carlos, CEP 13565-905, Brazil
| | - Lucas Guimarães Cardoso
- Departamento de Botânica (DB), Universidade Federal de São Carlos (UFSCar), Rod. Washington Luís km 235, São Paulo, São Carlos, CEP 13565-905, Brazil.
| | - Ana Teresa Lombardi
- Departamento de Botânica (DB), Universidade Federal de São Carlos (UFSCar), Rod. Washington Luís km 235, São Paulo, São Carlos, CEP 13565-905, Brazil
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17
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Ai X, Xin X, Wei W, Xie J, Hong J. Polysorbate-80 pretreatment contributing to volatile fatty acids production associated microbial interactions via acidogenic fermentation of waste activated sludge. BIORESOURCE TECHNOLOGY 2022; 345:126488. [PMID: 34871722 DOI: 10.1016/j.biortech.2021.126488] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 11/29/2021] [Accepted: 11/30/2021] [Indexed: 06/13/2023]
Abstract
Polyoxyethylene dehydration sorbitol monooleate (polysorbate-80) pretreatment enhanced volatile fatty acids (VFAs) production of waste activated sludge (WAS) in acidogenic fermentation. The results showed that polysorbate-80 ameliorated WAS solubilization obviously with a soluble chemical oxygen demand (SCOD) increasing to 1536 mg/L within 4 h. Within 2 days of acidogenic fermentation, the maximal VFAs arrived to 2958.35 mg COD/L via polysorbate-80-pretreatment. The polysorbate-80 pretreatment boosted microbial diversity and richness in fermentation process. The Clostridium, Macellibacteroides and Acidocella strengthened microbial cooperation for the metabolic functions enhancement (e.g. amino acid metabolism and carbohydrate metabolism) for VFAs generation from WAS organics. Overall, the polysorbate-80 could play positive roles on the transformation of organic matter from sludge solid matters to VFAs, which was turned out to become an effective enhancing strategy for future WAS treatment / bioresource recovery with relatively low cost.
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Affiliation(s)
- Xiaohuan Ai
- Department of Environmental Science and Engineering, Huaqiao University, Xiamen 361021, China; Xiamen Engineering Research Center of Industrial Wastewater Biochemical Treatment, Xiamen 361021, China; Fujian Provincial Research Center of Industrial Wastewater Biochemical Treatment (Huaqiao University), Xiamen 361021, China
| | - Xiaodong Xin
- Department of Environmental Science and Engineering, Huaqiao University, Xiamen 361021, China; Xiamen Engineering Research Center of Industrial Wastewater Biochemical Treatment, Xiamen 361021, China; Fujian Provincial Research Center of Industrial Wastewater Biochemical Treatment (Huaqiao University), Xiamen 361021, China
| | - Wenxuan Wei
- Department of Environmental Science and Engineering, Huaqiao University, Xiamen 361021, China; Xiamen Engineering Research Center of Industrial Wastewater Biochemical Treatment, Xiamen 361021, China; Fujian Provincial Research Center of Industrial Wastewater Biochemical Treatment (Huaqiao University), Xiamen 361021, China
| | - Jiaqian Xie
- Department of Environmental Science and Engineering, Huaqiao University, Xiamen 361021, China; Xiamen Engineering Research Center of Industrial Wastewater Biochemical Treatment, Xiamen 361021, China; Fujian Provincial Research Center of Industrial Wastewater Biochemical Treatment (Huaqiao University), Xiamen 361021, China
| | - Junming Hong
- Department of Environmental Science and Engineering, Huaqiao University, Xiamen 361021, China; Xiamen Engineering Research Center of Industrial Wastewater Biochemical Treatment, Xiamen 361021, China; Fujian Provincial Research Center of Industrial Wastewater Biochemical Treatment (Huaqiao University), Xiamen 361021, China.
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18
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Ji B, Liu C. CO 2 improves the microalgal-bacterial granular sludge towards carbon-negative wastewater treatment. WATER RESEARCH 2022; 208:117865. [PMID: 34826738 DOI: 10.1016/j.watres.2021.117865] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 11/08/2021] [Accepted: 11/09/2021] [Indexed: 06/13/2023]
Abstract
As a promising wastewater treatment technology, little is known about whether the greenhouse gas CO2 can be applied for microalgal-bacterial granular sludge (MBGS) process. This article applied CO2 for improving MBGS process. It was found that the physical structure of MBGS with no CO2 addition appeared to have a trend to be loose and disintegrated, with a sludge volume index at 5 min (SVI5) of over 150 mL/g and an average pore size of 35 nm in 60 d operation. However, CO2 could maintain the compact and integrated structure of MBGS with a SVI5 lower than 50 mL/g and an average pore size ranging from 10 to 13 nm. CO2 could enhance the production of extracellular polysaccharides and aromatic protein, thus favoring the granular stability of MBGS. CO2 could change the aqueous environment, e.g. lowering the pH values, which resulted in different microbial communities as well as metabolic potentials of MBGS. As for the reactor performance, CO2 could significantly improve the removals of organics and phosphorus, evidenced by the enhancement of genes encoding acetate-CoA ligase and ATPase, respectively. Although the mass ratio of algae to bacteria was elevated by CO2 addition, the ammonia removal related enzymes of glutamate dehydrogenase and glutamine synthetase could be negatively and positively impacted by CO2, respectively. Mass balance analysis of carbon indicated that CO2 could provide additional carbon source as well as enhance the buffering capacity for the MBGS system. Further estimations suggested that the MBGS process could achieve a carbon-negative objective for municipal wastewater treatment by supplying CO2 as additional carbon source. Hence, CO2 supply for MBGS process in municipal wastewater treatment can be deemed as a two-birds-one-stone strategy, i.e. maintaining the granular stability and eliminating the carbon emission. This article can advance our basic knowledge on MBGS process towards environment-sustainable wastewater treatment.
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Affiliation(s)
- Bin Ji
- Department of Water and Wastewater Engineering, Wuhan University of Science and Technology, Wuhan, 430065, China.
| | - Cheng Liu
- Department of Water and Wastewater Engineering, Wuhan University of Science and Technology, Wuhan, 430065, China
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19
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Fan S, Zhu L, Ji B. Deciphering the effect of light intensity on microalgal-bacterial granular sludge process for non-aerated municipal wastewater treatment. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102437] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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