1
|
Chen J, Zhang X, Zhou L, Zhu Z, Wu Z, Zhang K, Wang Y, Ju T, Ji X, Jin D, Wu P, Zhang X. Metagenomics insights into high-rate nitrogen removal from municipal wastewater by integrated nitrification, partial denitrification and Anammox at an extremely short hydraulic retention time. BIORESOURCE TECHNOLOGY 2023; 387:129606. [PMID: 37572889 DOI: 10.1016/j.biortech.2023.129606] [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: 06/26/2023] [Revised: 07/26/2023] [Accepted: 08/01/2023] [Indexed: 08/14/2023]
Abstract
To achieve high-rate nitrogen removal in municipal wastewater treatment through anaerobic ammonia oxidation (Anammox), the nitrification, partial denitrification, and Anammox processes were integrated by a step-feed strategy. An exceptional nitrogen removal load of 0.224 kg N/(m3·d) was achieved by gradient-reducing the hydraulic retention time (HRT) to 5 h. Metagenomic analysis demonstrated that Nitrosospira could express all genes encoding ammonia oxidation under low nitrogen and dissolved oxygen conditions (less than 0.5 mg/L), enabling complete nitrification. With the short of HRT, the relative abundance of Thauera increased from 2.8 % to 6.4 %. Frequent substrate exchanges at such extremely short HRT facilitated enhanced synergistic interactions among Nitrosospira, Thauera, and Candidatus Brocadia. These findings provide a comprehensive understanding of the utilization of Anammox combined processes for high-speed nitrogen removal in municipal wastewater treatment and the microbial interactions involved.
Collapse
Affiliation(s)
- Junjiang Chen
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, Suzhou 215009, China
| | - Xiaonong Zhang
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, Suzhou 215009, China
| | - Li Zhou
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, Suzhou 215009, China
| | - Zixuan Zhu
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, Suzhou 215009, China
| | - Zhiqiang Wu
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, Suzhou 215009, China
| | - Kangyu Zhang
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, Suzhou 215009, China
| | - Yiwen Wang
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, Suzhou 215009, China
| | - Ting Ju
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, Suzhou 215009, China
| | - Xu Ji
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, Suzhou 215009, China
| | - Da Jin
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, Suzhou 215009, China
| | - Peng Wu
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, Suzhou 215009, China; National and Local Joint Engineering Laboratory of Municipal Sewage Resource Utilization Technology, No. 1 Kerui Road, Suzhou 215009, China; Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, No. 1 Kerui Road,Suzhou 215009, China.
| | - Xingxing Zhang
- Shanghai Key Laboratory for Urban Ecological Processes and Eco-Restoration, Shanghai Engineering Research Center of Biotransformation of Organic Solid Waste, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| |
Collapse
|
2
|
Asgari G, Seid-Mohammadi A, Shokoohi R, Samarghandi MR, Daigger GT, Malekolkalami B, Khoshniyat R. Exposure of the static magnetic fields on the microbial growth rate and the sludge properties in the complete-mix activated sludge process (a Lab-scale study). Microb Cell Fact 2023; 22:195. [PMID: 37759209 PMCID: PMC10523802 DOI: 10.1186/s12934-023-02207-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 09/19/2023] [Indexed: 09/29/2023] Open
Abstract
BACKGROUND In this study, the effect of static magnetic fields (SMFs) on improving the performance of activated sludge process to enhance the higher rate of microbial growth biomass and improve sludge settling characteristics in real operation conditions of wastewater treatment plants has been investigated. The effect of SMFs (15 mT), hydraulic retention time, SRT, aeration time on mixed liquor suspended solids (MLSS) concentrations, mixed liquor volatile suspended solids (MLVSS) concentrations, α-factor, and pH in the complete-mix activated sludge (CMAS) process during 30 days of the operation, were evaluated. RESULTS There were not any differences between the concentration of MLSS in the case (2148.8 ± 235.6 mg/L) and control (2260.1 ± 296.0 mg/L) samples, however, the mean concentration of MLVSS in the case (1463.4 ± 419.2 mg/L) was more than the control samples (1244.1 ± 295.5 mg/L). Changes of the concentration of MLVSS over time, follow the first and second-order reaction with and without exposure of SMFs respectively. Moreover, the slope of the line and, the mean of α-factor in the case samples were 6.255 and, - 0.001 higher than the control samples, respectively. Changes in pH in both groups of the reactors were not observed. The size of the sluge flocs (1.28 µm) and, the spectra of amid I' (1440 cm-1) and II' (1650 cm-1) areas related to hydrogenase bond in the case samples were higher than the control samples. CONCLUSIONS SMFs have a potential to being considered as an alternative method to stimulate the microbial growth rate in the aeration reactors and produce bioflocs with the higher density in the second clarifiers.
Collapse
Affiliation(s)
- Ghorban Asgari
- Social Determinants of Health Research Center (SDHRC), Faculty of Public Health, Department of Environmental Health Engineering, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Abdolmotaleb Seid-Mohammadi
- Department of Environmental Health Engineering, School of Public Health, Research Centre for Health Sciences, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Reza Shokoohi
- Department of Environmental Health Engineering, School of Public Health, Research Centre for Health Sciences, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Mohammad Reza Samarghandi
- Department of Environmental Health Engineering, School of Public Health, Research Centre for Health Sciences, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Glen T Daigger
- Department of Civil and Environmental Engineering, University of Michigan, 177 EWRE Building, 1351 Beal Street, Ann Arbor, MI, 48109, USA
| | - Behrooz Malekolkalami
- Department of Physics, University of Kurdistan, P.O. Box 66177-15175, Sanandaj, Iran
| | - Ramin Khoshniyat
- Social Determinants of Health Research Center (SDHRC), Faculty of Public Health, Department of Environmental Health Engineering, Hamadan University of Medical Sciences, Hamadan, Iran.
| |
Collapse
|
3
|
Microaerophilic activated sludge system for ammonia retention from high-strength nitrogenous wastewater: biokinetics and mathematical modeling. Biochem Eng J 2022. [DOI: 10.1016/j.bej.2022.108790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
|
4
|
Muloiwa M, Dinka M, Nyende-Byakika S. Impact of temperature and airflow rate on the removal of organic pollutants and inorganic pollutants in the biological treatment process. SOUTH AFRICAN JOURNAL OF CHEMICAL ENGINEERING 2022. [DOI: 10.1016/j.sajce.2022.11.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
|
5
|
Li X, Zhao Y, Xu A, Chang H, Lin G, Li R. Conductive biochar promotes oxygen utilization to inhibit greenhouse gas emissions during electric field-assisted aerobic composting. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 842:156929. [PMID: 35753460 DOI: 10.1016/j.scitotenv.2022.156929] [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: 04/27/2022] [Revised: 06/19/2022] [Accepted: 06/20/2022] [Indexed: 06/15/2023]
Abstract
The insufficient oxygen supply in partial materials commonly results in significant greenhouse gas emissions during composting, which is essentially attributed to the poor electron transfer in the composting systems. Electric field-assisted aerobic composting (EAC) is considered effective in mitigation of greenhouse gas emissions, but the poor conductivity of composting materials hampers its efficiency and applicability. In this study, conductive biochar was added in the EAC system to investigate its effects on the performance and greenhouse gas emissions during the composting processes. In the system of EAC with biochar, the electrochemical properties, O2 utilization and composting performance were improved compared to the systems without biochar or assisted electric field. The maximum current of EAC with biochar was 0.32 A, higher than that without biochar (0.28A). Particularly, the peak concentrations of CH4 and N2O in the EAC system with biochar were 0.86 mg·kg-1 and 1.43 mg·kg-1, which were 45 % and 27 % lower than those in the EAC without biochar, respectively. The direct global warming potential attributed to CO2, CH4, and N2O was 3.96 g CO2-equivalent·kg-1 dry mass, providing a 31.6 % reduction compared to conventional composting. Microbial analyses revealed that biochar increased the relative abundance of electroactive bacteria including Bacillus, Tepidimicrobium and Corynebacterium. In contrast, the abundances of potential nitrifying and denitrifying bacterial species of Pseudomonas, Corynebacterium, Acinetobacter, and Bacillus were significantly lowered in the biochar-assisted EAC system (11.35 %). The results showed that the addition of biochar was able to promote the electrical conductivity of composting materials and accelerate the organic oxidation process by increasing O2 consumption, and accordingly change the dominant microbial community on both composting and biochar particles. This study verified the mechanism of the effectiveness of biochar in greenhouse gas control in composting processes, and thus provided evidence for facilitating the sustainable development of composting technologies.
Collapse
Affiliation(s)
- Xiang Li
- School of Environment, Beijing Normal University, Beijing 100875, China
| | - Yan Zhao
- School of Environment, Beijing Normal University, Beijing 100875, China.
| | - Ankun Xu
- School of Environment, Beijing Normal University, Beijing 100875, China
| | - Huiming Chang
- School of Environment, Beijing Normal University, Beijing 100875, China
| | - Guangnv Lin
- School of Environment, Beijing Normal University, Beijing 100875, China
| | - Rong Li
- School of Environment, Beijing Normal University, Beijing 100875, China
| |
Collapse
|
6
|
Newton K, Gonzalez E, Pitre FE, Brereton NJB. Microbial community origin and fate through a rural wastewater treatment plant. Environ Microbiol 2022; 24:2516-2542. [PMID: 35466495 DOI: 10.1111/1462-2920.16025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 04/20/2022] [Indexed: 11/29/2022]
Abstract
Conventional wastewater treatment relies on a complex microbiota; however, much of this community is still to be characterised. To better understand the origin, dynamics and fate of bacteria within a wastewater treatment plant: untreated primary wastewater, activated sludge, and post-treatment effluent were characterised. From 3,163 Exact Sequence Variants (ESVs), 860 were annotated to species-level. In primary wastewater, 28% of ESVs were putative bacterial species previously associated with humans, 14% with animals and 5% as common to the environment. Differential abundance analysis revealed significant relative reductions in ESVs from potentially humans-associated species from primary wastewater to activated sludge, and significant increases in ESVs from species associated with nutrient cycling. Between primary wastewater and effluent, 51% of ESVs from human-associated species did not significantly differ, and species such as Bacteroides massiliensis and Bacteroides dorei increased. These findings illustrate that activated sludge increased extracellular protease and urease-producing species, ammonia and nitrite oxidizers, denitrifiers and specific phosphorus accumulators. Although many human-associated species declined, some persisted in effluent, including strains of potential health or environmental concern. Species-level microbial assessment may be useful for understanding variation in wastewater treatment efficiency as well as for monitoring the release of microbes into surface water and the wider ecosystem. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
- Kymberly Newton
- Institut de Recherche en Biologie Végétale, Université de Montréal, Montréal, H1X 2B2, Canada
| | - Emmanuel Gonzalez
- Canadian Center for Computational Genomics, Department of Human Genetics, McGill University, Montréal, H3A 1A4, Canada
| | - Frederic E Pitre
- Institut de Recherche en Biologie Végétale, Université de Montréal, Montréal, H1X 2B2, Canada
| | - Nicholas J B Brereton
- Institut de Recherche en Biologie Végétale, Université de Montréal, Montréal, H1X 2B2, Canada
| |
Collapse
|
7
|
Jin B, Liu Y, Jia Y, Niu J, Wang L, Qin H, Wang R, Wang L, Ji J, Pang L, Du JJ. Simultaneous phosphorus and nitrogen removal with different C/N ratios in a low oxygen aeration system: Microorganisms and mechanisms. WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2022; 94:e10815. [PMID: 36514808 DOI: 10.1002/wer.10815] [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: 08/29/2022] [Revised: 11/04/2022] [Accepted: 11/13/2022] [Indexed: 06/17/2023]
Abstract
In this study, a combined system with simultaneous nitrification, denitrification, and phosphorus removal was operated in continuous low oxygen aeration mode, and the effect of lower oxygen aeration (dissolved oxygen [DO] 0.5-1.5 mg/L) on its performance was examined. The combined system consisted of sludge and high-efficiency biological packing and was operated using four carbon/nitrogen ratios (C/N) with being 10:1, 8:1, 6:1, 10:1. Experimental results showed that the combined system could perform an efficient nitrogen and phosphorus removal under low DO and C/N ratio of 8:1 condition, and removal efficiencies of chemical oxygen demand (COD), NH4 + -N, and PO4 3- -P were 80.01%, 99.03%, and 89.51%, respectively. High-throughput analysis indicated that the functional species of denitrifying bacteria, including Ferruginibacter Azospira, Comamonas, Bacilli, Hyphomicrobium, Thauera, and Comamonadaceae, were important participants in biological nutrient removal. Meanwhile, Acinetobacter was enriched in the combined system, which contributed to phosphorus removal. PRACTITIONER POINTS: A combined system was operated firstly under continuous low oxygen condition. The lower dissolved oxygen (DO) of the combined system was maintained at 0.50-1.5 mg/L level. The combined system could realize simultaneous phosphorus and nitrogen removal under C/N ratio of 8:1. Several functional bacteria were enriched in the coupled systems.
Collapse
Affiliation(s)
- Baodan Jin
- Henan Collaborative Innovation Center of Environmental Pollution Control and Ecological Restoration, School of Material and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou, China
| | - Ye Liu
- Henan Collaborative Innovation Center of Environmental Pollution Control and Ecological Restoration, School of Material and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou, China
| | - Yusheng Jia
- Henan Collaborative Innovation Center of Environmental Pollution Control and Ecological Restoration, School of Material and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou, China
| | - Jintao Niu
- Henan Hengan Environmental Protection Technology Co., Ltd, Zhengzhou, China
| | - Lipei Wang
- Henan Geological Bureau, Zhengzhou, China
| | - Hexian Qin
- Henan Collaborative Innovation Center of Environmental Pollution Control and Ecological Restoration, School of Material and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou, China
| | - Ran Wang
- Henan Collaborative Innovation Center of Environmental Pollution Control and Ecological Restoration, School of Material and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou, China
| | - Lan Wang
- Henan Collaborative Innovation Center of Environmental Pollution Control and Ecological Restoration, School of Material and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou, China
| | - Jiantao Ji
- College of Ecology and Environment, Zhengzhou University, Zhengzhou, China
| | - Long Pang
- Henan Collaborative Innovation Center of Environmental Pollution Control and Ecological Restoration, School of Material and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou, China
| | - Jing Jing Du
- Henan Collaborative Innovation Center of Environmental Pollution Control and Ecological Restoration, School of Material and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou, China
| |
Collapse
|
8
|
Evaluating acute toxicity in enriched nitrifying cultures: Lessons learned. J Microbiol Methods 2021; 192:106377. [PMID: 34798174 DOI: 10.1016/j.mimet.2021.106377] [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: 11/03/2021] [Revised: 11/14/2021] [Accepted: 11/14/2021] [Indexed: 11/22/2022]
Abstract
Toxicological batch assays are essential to assess a compound's acute effect on microorganisms. This methodology is frequently employed to evaluate the effect of contaminants in sensitive microbial communities from wastewater treatment plants (WWTPs), such as autotrophic nitrifying populations. However, despite nitrifying batch assays being commonly mentioned in the literature, their experimental design criteria are rarely reported or overlooked. Here, we found that slight deviations in culture preparations and conditions impacted bacterial community performance and could skew assay results. From pre-experimental trials and experience, we determined how mishandling and treatment of cultures could affect nitrification activity. While media and biomass preparations are needed to establish baseline conditions (e.g., biomass washing), we found extensive centrifugation selectively destabilised nitrification activities. Further, it is paramount that the air supply is adjusted to minimise nitrite build-up in the culture and maintain suitable aeration levels without sparging ammonia. DMSO and acetone up to 0.03% (v/v) were suitable organic solvents with minimal impact on nitrification activity. In the nitrification assays with allylthiourea (ATU), dilute cultures exhibited more significant inhibition than concentrated cultures. So there were biomass-related effects; however, these differences minimally impacted the EC50 values. Using different nutrient-media compositions had a minimal effect; however, switching mineral media for the toxicity test from the original cultivation media is not recommended because it reduced the original biomass nitrification capacity. Our results demonstrated that these factors substantially impact the performance of the nitrifying inoculum used in acute bioassays, and consequently, affect the response of AOB-NOB populations during the toxicant exposure. These are not highlighted in operation standards, and unfortunately, they can have significant consequential impacts on the determinations of toxicological endpoints. Moreover, the practical procedures tested here could support other authors in developing testing methodologies, adding quality checks in the experimental framework with minimal waste of time and resources.
Collapse
|
9
|
Belli TJ, Bassin JP, Costa RE, Akaboci TRV, Battistelli AA, Lobo-Recio MA, Lapolli FR. Evaluating the effect of air flow rate on hybrid and conventional membrane bioreactors: Implications on performance, microbial activity and membrane fouling. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 755:142563. [PMID: 33059133 DOI: 10.1016/j.scitotenv.2020.142563] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 09/04/2020] [Accepted: 09/22/2020] [Indexed: 06/11/2023]
Abstract
This study addressed the impact of air flow rate on the performance, membrane fouling behaviour and microbial community of a sequencing batch conventional membrane bioreactor (SB-MBR) and a sequencing batch hybrid membrane bioreactor (SB-HMBR) with carrier media for biofilm growth. Two different scenarios were evaluated: high (6.4 L min-1) and low (1.6 L min-1) air flow rates, associated with high (4.5 mg L-1) and low (1.5 mg L-1) dissolved oxygen (DO) concentrations and specific aeration demand per membrane area (SADm) of 0.426 and 0.106 m3 m-2 h-1, respectively. Both reactors were subjected to alternating non-aerated and aerated conditions for organic matter (as chemical oxygen demand - COD), nitrogen and phosphate removal from a municipal wastewater. From the bacterial community analysis, the key players in nutrient removal processes were assessed. The results showed that COD removal efficiencies were above 95% in both MBRs, regardless of the aeration intensity, while complete ammonium removal was observed at the higher DO. However, nitrifying activity was adversely affected under low DO levels. High nitrification levels were re-established faster in the hybrid MBR, thanks to the presence of biofilm, where nitrifying activity was favoured and the bacterial community profile did not exhibit substantial changes upon DO reduction. A higher denitrification potential was found for the carrier-based MBR, resulting in lower effluent nitrate concentrations. Regarding phosphorus removal, a slight improvement was observed in the SB-HMBR at reduced DO, while in the SB-MBR it remained practically constant. Moreover, the specific phosphate uptake rate exhibited a significant increase, especially in the hybrid MBR, reaching 44.6 mgP gVSS-1 h-1. At lower aeration rate, however, worse filterability and higher membrane fouling rates were observed, especially in the conventional MBR. Overall, the results demonstrated that the hybrid MBR better withstood the reduced air flow rate and DO as compared to the conventional counterpart.
Collapse
Affiliation(s)
- Tiago J Belli
- Dept. of Sanitary Engineering, State University of Santa Catarina, 89140-000 Ibirama, SC, Brazil.
| | - João P Bassin
- Chemical Engineering Program - COPPE, Federal University of Rio de Janeiro, P.O. Box 68502, 21941-972 Rio de Janeiro, RJ, Brazil.
| | - Rayra E Costa
- Dept. of Sanitary and Environmental Engineering, Federal University of Santa Catarina Florianópolis, SC, Brazil
| | - Tiago R V Akaboci
- Dept. of Sanitary Engineering, State University of Santa Catarina, 89140-000 Ibirama, SC, Brazil
| | - André A Battistelli
- Dept. of Environmental Engineering, State University of Maringá, Umuarama, PR, Brazil
| | - Maria A Lobo-Recio
- Dept. of Energy and Sustainability, Federal University of Santa Catarina, Araranguá, SC 88906-072, Brazil
| | - Flávio R Lapolli
- Dept. of Sanitary and Environmental Engineering, Federal University of Santa Catarina, Florianópolis, SC, Brazil
| |
Collapse
|
10
|
Wang L, Li B, Li Y, Wang J. Enhanced biological nitrogen removal under low dissolved oxygen in an anaerobic-anoxic-oxic system: Kinetics, stoichiometry and microbial community. CHEMOSPHERE 2021; 263:128184. [PMID: 33297151 DOI: 10.1016/j.chemosphere.2020.128184] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 08/24/2020] [Accepted: 08/27/2020] [Indexed: 05/26/2023]
Abstract
A lab-scale anaerobic-anoxic-oxic system was used to investigate the nitrogen removal mechanism under low dissolved oxygen (DO) conditions. When DO was decreased from 2 to 0.5 mg L-1, chemical oxygen demand (COD) and NH4+ removals were not influenced, while total nitrogen removal increased from 69% to 79%. Further batch tests indicated that both the specific nitrification rate and denitrification rate greatly increased under low DO conditions. When DO was decreased from 2 to 0.5 mg L-1, the oxygen half saturation constant value for ammonia oxidizing bacteria (AOB) decreased from 0.39 to 0.29 mg-O2 L-1, and for nitrite oxidizing bacteria (NOB), it reduced from 0.29 to 0.09 mg-O2 L-1. Correspondingly, the observed yield coefficients increased from 0.05 to 0.10 mg-cell mg-1-N for AOB, and from 0.02 to 0.06 mg-cell mg-1-N for NOB. High-throughput sequencing revealed that the relative abundances of AOB increased from 6.13% to 6.54%, Nitrospira-like NOB increased from 3.67% to 6.50%, and denitrifiers increased from 2.84% to 7.04%. Improved simultaneous nitrification and denitrification under low DO conditions contributed to the enhanced nitrogen removal.
Collapse
Affiliation(s)
- Lin Wang
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, People's Republic of China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, People's Republic of China
| | - Bingrong Li
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, People's Republic of China
| | - Yongmei Li
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, People's Republic of China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, People's Republic of China.
| | - Jianmin Wang
- Department of Civil, Architectural and Environmental Engineering, Missouri University of Science and Technology, Rolla, MO, 65409, USA
| |
Collapse
|
11
|
Egbuikwem PN, Mierzwa JC, Saroj DP. Evaluation of aerobic biological process with post-ozonation for treatment of mixed industrial and domestic wastewater for potential reuse in agriculture. BIORESOURCE TECHNOLOGY 2020; 318:124200. [PMID: 33035946 DOI: 10.1016/j.biortech.2020.124200] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 09/22/2020] [Accepted: 09/27/2020] [Indexed: 05/23/2023]
Abstract
Suspended growth biological process (SGBP) with post-ozonation (O3) was investigated for treatment of simulated complex mixed industrial and domestic wastewater at specific conditions. The SGBP was operated under complete aeration, 30/30-min and 60/30-min on/off aeration cycles and effluent was exposed to ozone at 250 mgO3/h fixed dose and contact time 1 to 60-min. The SGBP performance was maximum under 60/30-min aeration conditions achieving 92.1, 90.6, 83.3 and 83.8% reduction in COD, BOD5, TN and PO4-P respectively. Nitrification (64.1%) was uninhibited even on transition to pulse aeration cycles. The concentrations of diesel oil and methylene blue dye were reduced by 83.6 and 93.5% respectively. Post-ozonation oxidized residual organics up to 19.9%, based on COD measurement, and increased effluent BOD5 up to 49.5%. The results including the crop growth outcomes indicate that SGBP-O3 process has great potential to improve the quality of mixed industrial and domestic wastewater considerably for various water reuse applications.
Collapse
Affiliation(s)
- Precious Nneka Egbuikwem
- Centre for Environmental Health and Engineering (CEHE), Department of Civil and Environmental Engineering, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH, United Kingdom; Department of Agricultural and Environmental Engineering, School of Engineering Technology, Imo State Polytechnic Umuagwo, P. M. B. 1472, Owerri, Nigeria
| | - Jose Carlos Mierzwa
- Polytechnic School, Department of Hydraulic and Environmental Engineering, Av. Almeida Prado, 83 - Building, Civil Engineering/PHA Butanta, 05508-900, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Devendra Prakash Saroj
- Centre for Environmental Health and Engineering (CEHE), Department of Civil and Environmental Engineering, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH, United Kingdom.
| |
Collapse
|
12
|
How SW, Nittami T, Ngoh GC, Curtis TP, Chua ASM. An efficient oxic-anoxic process for treating low COD/N tropical wastewater: Startup, optimization and nitrifying community structure. CHEMOSPHERE 2020; 259:127444. [PMID: 32640378 DOI: 10.1016/j.chemosphere.2020.127444] [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: 04/24/2020] [Revised: 06/08/2020] [Accepted: 06/15/2020] [Indexed: 05/26/2023]
Abstract
In this study, we assessed and optimized a low-dissolved-oxygen oxic-anoxic (low-DO OA) process to achieve a low-cost and sustainable solution for wastewater treatment systems in the developing tropical countries treating low chemical oxygen demand-to-nitrogen ratio (COD/N) wastewater. The low-DO OA process attained complete ammonia removal and the effluent nitrate nitrogen (NO3-N) was below 0.3 mg/L. The recommended hydraulic retention time and sludge retention time (SRT) were 16 h and 20 days, respectively. The 16S rRNA sequencing data revealed that long SRT (20 days) encouraged the growth of nitrite-oxidizing bacteria (NOB) affiliated with "Candidatus Nitrospira defluvii". Comammox made up 10-20% of the Nitrospira community. NOB and comammox related to Nitrospira were enriched at long SRT (20 days) to achieve good low-DO nitrification performance. The low-DO OA process was efficient and has simpler design than conventional processes, which are keys for sustainable wastewater treatment systems in the developing countries treating low COD/N wastewater.
Collapse
Affiliation(s)
- Seow Wah How
- Department of Chemical Engineering, Faculty of Engineering, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Tadashi Nittami
- Division of Materials Science and Chemical Engineering, Faculty of Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama, 240-8501, Japan
| | - Gek Cheng Ngoh
- Department of Chemical Engineering, Faculty of Engineering, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Thomas P Curtis
- School of Engineering, Newcastle University, Newcastle Upon Tyne, NE1 7RU, United Kingdom
| | - Adeline Seak May Chua
- Department of Chemical Engineering, Faculty of Engineering, University of Malaya, 50603, Kuala Lumpur, Malaysia.
| |
Collapse
|
13
|
Nam K, Heo S, Loy-Benitez J, Ifaei P, Yoo C. An autonomous operational trajectory searching system for an economic and environmental membrane bioreactor plant using deep reinforcement learning. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2020; 81:1578-1587. [PMID: 32644951 DOI: 10.2166/wst.2020.053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Optimal operation of membrane bioreactor (MBR) plants is crucial to save operational costs while satisfying legal effluent discharge requirements. The aeration process of MBR plants tends to use excessive energy for supplying air to micro-organisms. In the present study, a novel optimal aeration system is proposed for dynamic and robust optimization. Accordingly, a deep reinforcement learning (DRL)-based optimal operating system is proposed, so as to meet stringent discharge qualities while maximizing the system's energy efficiency. Additionally, it is compared with the manual system and conventional reinforcement learning (RL)-based systems. A deep Q-network (DQN) algorithm automatically learns how to operate the plant efficiently by finding an optimal trajectory to reduce the aeration energy without degrading the treated water quality. A full-scale MBR plant with the DQN-based autonomous aeration system can decrease the MBR's aeration energy consumption by 34% compared to other aeration systems while maintaining the treatment efficiency within effluent discharge limits.
Collapse
Affiliation(s)
- KiJeon Nam
- Department of Environmental Science and Engineering, Kyung Hee University, 1732, Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do, 17104, Republic of Korea E-mail: ; † The first and second authors contributed equally to this paper
| | - SungKu Heo
- Department of Environmental Science and Engineering, Kyung Hee University, 1732, Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do, 17104, Republic of Korea E-mail: ; † The first and second authors contributed equally to this paper
| | - Jorge Loy-Benitez
- Department of Environmental Science and Engineering, Kyung Hee University, 1732, Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do, 17104, Republic of Korea E-mail:
| | - Pouya Ifaei
- Department of Environmental Science and Engineering, Kyung Hee University, 1732, Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do, 17104, Republic of Korea E-mail:
| | - ChangKyoo Yoo
- Department of Environmental Science and Engineering, Kyung Hee University, 1732, Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do, 17104, Republic of Korea E-mail:
| |
Collapse
|
14
|
Optimization of Wastewater Phosphorus Removal in Winter Temperatures Using an Anaerobic–Critical Aerobic Strategy in a Pilot-Scale Sequencing Batch Reactor. WATER 2019. [DOI: 10.3390/w12010110] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Biological phosphorus removal using an anaerobic–aerobic sequencing batch reactor (SBR) in a low temperature can be difficult to remove, and aeration always accounts for nearly half of the total electricity costs at many wastewater treatment plants. In this study, a pilot-scale anaerobic–critical aerobic SBR (A–CA SBR) was developed for synthetic domestic wastewater. More importantly, the phase, whose concentration of diffused oxygen was controlled at 1.0–1.5 mg/L, was defined as a critical aerobic phase, which reduced expenses during the operation. To be specific, half of the ammonia was removed within 10 days and no NO3−–N was accumulated during the process. From the SEM and metagenome analysis, Rhodocyclus, Zooglea, Dechloromonas, and Simplicispira had the ability to remove phosphorus and NO3−–N simultaneously, which proved the existence of a potential double-layer sludge structure under an A–CA operational condition. All of the results disclose that the pilot-scale A–CA SBR is a reliable manipulation strategy for phosphorus removal under low temperatures, which can hopefully apply to practical wastewater remediation.
Collapse
|
15
|
Rada-Ariza A, Fredy D, Lopez-Vazquez C, Van der Steen N, Lens P. Ammonium removal mechanisms in a microalgal-bacterial sequencing-batch photobioreactor at different solids retention times. ALGAL RES 2019. [DOI: 10.1016/j.algal.2019.101468] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
16
|
Tang J, Li X, Zhao W, Wang Y, Cui P, Zeng RJ, Yu L, Zhou S. Electric field induces electron flow to simultaneously enhance the maturity of aerobic composting and mitigate greenhouse gas emissions. BIORESOURCE TECHNOLOGY 2019; 279:234-242. [PMID: 30735933 DOI: 10.1016/j.biortech.2019.01.140] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Revised: 01/27/2019] [Accepted: 01/29/2019] [Indexed: 06/09/2023]
Abstract
The long maturation period and greenhouse gas (GHG) emission are two major problems that arise during aerobic composting, mainly due to the low efficiency of O2 transmission and utilization. In this study, a novel electric-field-assisted aerobic composting (EAC) process was tested by simply applying a direct-current voltage of 2 V to a conventional aerobic composting (CAC) process. Compared with the CAC process, the maturation time and the total GHG for the EAC process were reduced by 33% and 70%, respectively. Furthermore, the analyses of O2 consumption and microbial communities demonstrated that the electric field had enhanced O2 utilization by 30 ± 9% and increased the relative abundance of electroactive bacteria by about 3.4-fold compared to CAC. This work has represented a proof of principle for EAC and suggests that the electric field is an effective and environmentally friendly strategy for enhancing compost maturity and mitigating GHG emissions during aerobic composting.
Collapse
Affiliation(s)
- Jiahuan Tang
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Xiang Li
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Wenqi Zhao
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yajun Wang
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Peng Cui
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Raymond Jianxiong Zeng
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Linpeng Yu
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Shungui Zhou
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| |
Collapse
|
17
|
Optimal Surface Aeration Control in Full-Scale Oxidation Ditches through Energy Consumption Analysis. WATER 2018. [DOI: 10.3390/w10070945] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Oxidation ditches are popularly used in rural areas and decentralized treatment facilities where energy deficiency is of concern. Aeration control technologies are well established for diffusion systems in order to improve energy efficiency, but there are still challenges in their application in oxidation ditches because surface aerators have unique characteristics with respect to oxygen transfer and energy consumption. In this paper, an integral energy model was proposed to include the energy, aeration, and fluidic effects of surface aerators, by which the energy for aeration of each aerator can be estimated using online data. Two types of rotating disks with different diameters (1800 mm and 1400 mm) were monitored in situ to estimate the model parameters. Furthermore, a feedforward–feedback loop control strategy was proposed using the concept of energy analysis and optimization. The simplified control system was implemented in a full-scale Orbal oxidation ditch, achieving an approximately 10% saving in full-process energy consumption. The cost–benefit analysis and carbon emission assessment confirmed the economic feasibility and environmental contribution of the control system. The energy model can help process designers and operators to better understand and optimally control the aeration process in oxidation ditches.
Collapse
|
18
|
Sato R, Hayashi K, Tomiyama A. Effects of Azimuthal Angle of Aeration Hole and Liquid Viscosity on Flows Inside and Outside an Air Diffuser Pipe. KAGAKU KOGAKU RONBUN 2018. [DOI: 10.1252/kakoronbunshu.44.59] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Ryo Sato
- Graduate School of Engineering, Kobe University
| | | | | |
Collapse
|