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Gao X, Liu Y, Tang C, Lu M, Zou J, Li Z. Evaluating river health through respirogram metrics: Insights from the Weihe River basin, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 919:170805. [PMID: 38342463 DOI: 10.1016/j.scitotenv.2024.170805] [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: 10/23/2023] [Revised: 01/18/2024] [Accepted: 02/06/2024] [Indexed: 02/13/2024]
Abstract
Human activities pose a significant threat to rivers, requiring robust assessment methods for effective river management. This study focuses on the Weihe River Basin in Shaanxi province and introduces the respirogram as an innovative assessment technique. The respirogram allows the simultaneous assessment of river health from two important aspects: pollution levels and microbial status. Specifically, the in-situ respiration ratio (Rs/t) serves as an indicator of pollution, with higher Rs/t values correlating with increased pollution levels. Conversely, the recovery index (RI) measures microbial vitality, with values below 0.15 indicating greater microbial activity and recovery potential. Using predefined thresholds of Rs/t = 0.3 and RI = 0.15, water bodies were categorized into four types. For example, rivers with Rs/t > 0.3 and RI > 0.15 were identified as receiving sewage, characterized by high pollution and low microbial vitality. Similarly, different assessment criteria delineated urban rivers, natural rivers, and wastewater treatment plants. Based on these classifications, targeted engineering measures were proposed to enhance the self-purification capabilities of rivers of different statuses.
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Affiliation(s)
- Xingdong Gao
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Xi'an Key Laboratory of Intelligent Equipment Technology for Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Yanxia Liu
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Xi'an Key Laboratory of Intelligent Equipment Technology for Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Congcong Tang
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Xi'an Key Laboratory of Intelligent Equipment Technology for Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Meng Lu
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Xi'an Key Laboratory of Intelligent Equipment Technology for Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Jiageng Zou
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Xi'an Key Laboratory of Intelligent Equipment Technology for Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Zhihua Li
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Xi'an Key Laboratory of Intelligent Equipment Technology for Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
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Li ZH, Yang JW, Zhang H. Increase metabolic heat to compensate for low temperature in activated sludge systems. WATER RESEARCH 2024; 250:121068. [PMID: 38154337 DOI: 10.1016/j.watres.2023.121068] [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: 08/16/2023] [Revised: 12/01/2023] [Accepted: 12/23/2023] [Indexed: 12/30/2023]
Abstract
The efficient operation of activated sludge systems is frequently hindered by low temperatures, and extensive research has been conducted to overcome this difficulty. However, the effect of varying temperatures on heat generation during substrate degradation remains unclear. In this study, results from laboratory-scale reactors show that sludge generated 5.36 ± 0.58 J/mg COD, 4.45 ± 0.24 J/mg COD, and 4.22 ± 0.26 J/mg COD at 10 °C, 20 °C, and 30 °C under aerobic conditions, respectively. Similarly, the sludge generated 4.05 ± 0.31 J/mg COD, 2.37 ± 0.15 J/mg COD, and 2.89 ± 0.18 J/mg COD under anoxic conditions. Despite the decreased respiration rates and hence reduced pollutant removal efficiency, sludge exhibited effective heat generation at low temperatures. Results from the full-scale plant also show a negative correlation between the heat generation capacity of microorganisms and the temperatures. 14.2 °C is considered the critical wastewater temperature for microorganisms' heat generation to offset the investigated plant's heat dissipation. This observation verified that thermal compensation for low temperatures was also significant in the full-scale plant. The mechanism of low-temperature compensation is attributed to non-growth processes being less dependent on temperature than growth processes, resulting in slow microbial growth but high heat generation at low temperatures. These findings provide valuable insights into the design and sustainable operation of wastewater treatment plants.
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Affiliation(s)
- Zhi-Hua Li
- Key Laboratory of Northwest Water Resource, Environment, and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Xi'an Key Laboratory of Intelligent Equipment Technology for Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
| | - Jia-Wei Yang
- Key Laboratory of Northwest Water Resource, Environment, and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Xi'an Key Laboratory of Intelligent Equipment Technology for Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Hao Zhang
- Key Laboratory of Northwest Water Resource, Environment, and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Xi'an Key Laboratory of Intelligent Equipment Technology for Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
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Wen ZH, Zhang SS, Zhao P, Hang ZY, He ZW, Yu HQ, Li ZH. Roles of high/low nucleic acid bacteria in flocs and probing their dynamic migrations with respirogram. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 895:165108. [PMID: 37356771 DOI: 10.1016/j.scitotenv.2023.165108] [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: 04/11/2023] [Revised: 06/09/2023] [Accepted: 06/22/2023] [Indexed: 06/27/2023]
Abstract
Bacterial migration is crucial for the stability of activated sludge but rarely reported. The static distribution was explored by changes in bacteria concentration with extracellular polymeric substances (EPS) extractions. Next, denitrification and aeration were conducted as normal running conditions for examining the bacterial migration between floc-attached and dispersed growth. Above observations were further explored by conducting copper ion (Cu2+) shock as an extreme running condition. After extracting EPS, low nucleic acid (LNA) bacteria migrated from the sludge to the supernatant primarily, and high nucleic acid (HNA) bacteria remained in the residual sludge, suggesting that HNA bacteria mainly distributed inside the sludge while LNA bacteria outside the sludge. During the denitrification process, LNA bacteria migrated out of flocs, which increased by 6.94 × 106 events/mL in the supernatant. During the feast phase of aeration, LNA bacteria grew attached to flocs, causing the increased flocs diameter from 45.60 to 47.40 μm. During the following aerobic famine phase, LNA bacteria grew dispersedly, but HNA bacteria remained unchanged. However, a further severe famine phase drove HNA bacteria to be dispersed, breaking flocs with the decreased diameter from 48.10 to 46.50 μm. When the Cu2+ shock was employed, LNA and HNA bacteria increased but the LNA/HNA ratio decreased in the supernatant, indicating more HNA bacteria migrating to the dispersed phase. From a structural perspective, HNA bacteria distributed inside the sludge and functioned as the backbone of flocs, undertaking the maintenance of flocs stability primarily; while LNA bacteria distributed outside the sludge and functioned as filling materials, having a secondary influence on flocs stability. These processes were also probed by respirogram exactly, correlating the system-scale measurement and microscale migrations and providing an early warning signal under abnormal circumstances. The processed HNA-backbone theory is promising for regulating the stability of activated sludge based on bacterial migrations.
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Affiliation(s)
- Zheng-Hong Wen
- Key Laboratory of Northwest Water Resource, Environment, and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Shuang-Shuang Zhang
- Key Laboratory of Northwest Water Resource, Environment, and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Pian Zhao
- Key Laboratory of Northwest Water Resource, Environment, and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Zhen-Yu Hang
- Key Laboratory of Northwest Water Resource, Environment, and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Zhang-Wei He
- Key Laboratory of Northwest Water Resource, Environment, and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Han-Qing Yu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Zhi-Hua Li
- Key Laboratory of Northwest Water Resource, Environment, and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Xi'an Key Laboratory of Intelligent Equipment Technology for Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
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4
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Hang Z, Tong P, Zhao P, He Z, Shao L, Jia Y, Wang XC, Li Z. Hierarchical stringent response behaviors of activated sludge system to stressed conditions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 870:161832. [PMID: 36716870 DOI: 10.1016/j.scitotenv.2023.161832] [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: 12/27/2022] [Revised: 01/18/2023] [Accepted: 01/21/2023] [Indexed: 06/18/2023]
Abstract
The stringent response of activated sludge systems to either stressed or harmful environments is important for the stable operation of activated sludge, which is examined by taking copper ion (Cu2+) as a stress model in this study. When weak stress was employed (Cu2+ ≤ 2.5 mg/L), the N-acyl-homoserine lactones (AHLs) of C6-, C8-, and C10-HSL increased by 30 %, 13 %, and 127 %, respectively, while the redox sensor green (RSG) intensity decreased by 28 %. Encountering the increased stress (2.5 mg/L < Cu2+ ≤ 5 mg/L), bacteria concentration in the supernatant increased by 87 %. However, the respiration rates of autotrophic and heterotrophic bacteria (SOURa and SOURh) and adenosine triphosphate decreased by 52 %, 18 %, and 27 %, respectively, and the flocs disintegrated with a diameter decreasing from 57 to 51 μm. When the stress became more serious (Cu2+ > 5 mg/L), the respiration rates continued to decline, but the quasi-endogenous respiration ratio (Rq/t) increased from 31 % to 47 %. Negligible changes occurred in the endogenous respiration rate (SOURe), adenosine diphosphate, and adenosine monophosphate. Based on these results, a hierarchical stringent response model of the activated sludge system to stressed conditions was proposed, and these responses were evaluated by respirogram. The initial response to weak stress was related to the most sensitive signals of quorum sensing and RSG intensity, well described by the quasi-endogenous respiration rate. The adaptive response to increased stress was the proactive migrations of low- and high-nucleic-acid bacteria to the supernatant, causing the looseness and even disintegration of sludge flocs, well described by SOURa, SOURh, and Rq/t. The lethal response to lethal stress was related to endogenous metabolic processes, well described by SOURe. This work provides new insights into understanding the stringent response of activated sludge systems to some stressed conditions. It helps to regulate the stability of activated sludge systems with respirogram technology.
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Affiliation(s)
- Zhenyu Hang
- Key Laboratory of Northwest Water Resource, Environment, and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Peipei Tong
- Key Laboratory of Northwest Water Resource, Environment, and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Pian Zhao
- Key Laboratory of Northwest Water Resource, Environment, and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Zhangwei He
- Key Laboratory of Northwest Water Resource, Environment, and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Linjun Shao
- Key Laboratory of Northwest Water Resource, Environment, and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Yanru Jia
- Key Laboratory of Northwest Water Resource, Environment, and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Xiaochang C Wang
- Key Laboratory of Northwest Water Resource, Environment, and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Zhihua Li
- Key Laboratory of Northwest Water Resource, Environment, and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Xi'an Key Laboratory of Intelligent Equipment Technology in Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
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5
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Li Z, Zhang Y, Hang Z, Lu M, Wang H, Gao X, Zhang R. A novel approach to estimate and control denitrification performance in activated sludge systems with respirogram technology. J Environ Sci (China) 2022; 121:112-121. [PMID: 35654502 DOI: 10.1016/j.jes.2021.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 09/07/2021] [Accepted: 09/07/2021] [Indexed: 06/15/2023]
Abstract
Respirogram technology has been widely applied for aerobic process, however, the response of respirogram to anoxic denitrification is still unclear. To reveal such response may help to design a new method for the evaluation of the performance of denitrification. The size distribution of flocs measured at different denitrification moments demonstrated a clear expansion of flocs triggered by denitrification, during which higher specific endogenous and quasi-endogenous respiration rates (SOURe and SOURq) were also observed. Furthermore, SOURq increases exponentially with the specific denitrification rate (SDNR), suggesting that there should be a maximum SDNR in conventional activated sludge systems. Based on these findings, an index Rq/t, defined as the ratio of quasi-endogenous (OURq) to maximum respiration rate (OURt), is proposed to estimate the denitrification capacity that higher Rq/t indicates higher denitrification potential, which can be readily obtained without complex measurement or analysis, and it offers a novel and promising respirogram-based approach for denitrification estimation and control by taking measures to extend anoxic time to maintain its value at a high level within a certain range.
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Affiliation(s)
- Zhihua Li
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
| | - Yali Zhang
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Zhenyu Hang
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Meng Lu
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Haiguang Wang
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Xingdong Gao
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Ruina Zhang
- Shanghai Environmental & Sanitary Engineering Design Institute Co. Ltd., Shanghai 200232, China
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Hang Z, Li Z, Zhu Y, Zhang J, Yang F, Zhang T. A new approach to evaluate and improve the stability of aerobic sludge systems based on maintenance coefficient. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 296:113192. [PMID: 34252857 DOI: 10.1016/j.jenvman.2021.113192] [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: 02/26/2021] [Revised: 05/31/2021] [Accepted: 06/28/2021] [Indexed: 06/13/2023]
Abstract
Stability is a key issue of wastewater treatment plants using either aerobic granular (AGS) or conventional activated sludge (CAS). The two forms of aerobic sludge were cultivated under different conditions to study the main factors affecting their stability. It was found that maintenance coefficient (m) describing the fraction of non-growth energy of granules increased significantly when the system became more stable during processes with the enhancement of granulation and the periodic short-term shock load. The yield coefficient (YH) was the main factor affecting the m value, and the inhibition in YH value was able to promote the maintenance potential according to the kinetic equation. Therefore, strategies that promote the maintenance coefficient could be applied to improve the stability of sludge systems, including inhibiting the yield rate and taking periodic short-term shock. Evaluation of stability based on the maintenance coefficient is a promising tool for ensuring the stable operation of wastewater treatment processes.
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Affiliation(s)
- Zhenyu Hang
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Zhihua Li
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China.
| | - Yuanmo Zhu
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Jing Zhang
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Fan Yang
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Tianyu Zhang
- Department of Mathematical Sciences, Montana State University, Bozeman, MT, 59717-2400, USA
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7
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Li ZH, Guo Y, Hang ZY, Zhang TY, Yu HQ. Simultaneous evaluation of bioactivity and settleability of activated sludge using fractal dimension as an intermediate variable. WATER RESEARCH 2020; 178:115834. [PMID: 32339865 DOI: 10.1016/j.watres.2020.115834] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 03/25/2020] [Accepted: 04/13/2020] [Indexed: 06/11/2023]
Abstract
Bioactivity and settleability of activated sludge are essential for the operation of activated sludge systems in wastewater treatment. In this work, the fractal dimension of sludge image is proposed as a tool to evaluate these two factors. The specific endogenous respiration rate (SOURe) and the specific quasi-endogenous respiration rate (SOURq) are found to be more dependent on the 3D structure of sludge than the specific total respiration rate (SOURt). The relationship between the fractal structure and bioactivity suggests that the bioactivity governs the acceptable upper bound of the fractal dimension (Df), as at its theoretical maximum of 2.0, the non-porous compact flocs are predominant. The settleability or the biomass concentration determines the acceptable lower bound of Df, as at its theoretical minimum of 1.0, the free-swimming microbes are predominant. Our data reveal that the activated sludge has an acceptable fractal dimension Df in a range of 1.07-1.68. In practice, the fractal dimension should be controlled at a reasonable value as there is a trade-off between the bioactivity and physical structure to achieve better performance. A decrease or increase in the fractal dimension can serve as a signal for the change of the operational status, and this is further elucidated from the perspective of settling tanks using state point analysis. Compared with respirogram measurement, measuring fractal dimension is a complex process and its online implementation is challenging. Also, the measured value varies with the methods used. In addition, the difference in their theoretical values depends on the homogeneity of the sludge structure. Since the fractal dimension Df reflects both bioactivity and settleability of the sludge but is difficult to measure, in this work a relationship between Df and the easily measurable respirogram is established, and a method using the respirogram as a proxy of Df is proposed to control the bioactivity and settleability simultaneously. This respiration-based method is able to simultaneously control aeration and settling tanks, and could serve as an efficient tool for the management of wastewater treatment plants.
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Affiliation(s)
- Zhi-Hua Li
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China.
| | - Yao Guo
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Zhen-Yu Hang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Tian-Yu Zhang
- Department of Mathematical Sciences, Montana State University, Bozeman, MT, 59717-2400, USA
| | - Han-Qing Yu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Applied Chemistry, University of Science & Technology of China, Hefei, 230026, China.
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Sun C, Zhang B, Chen Z, Qin W, Wen X. Sludge retention time affects the microbial community structure: A large-scale sampling of aeration tanks throughout China. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 261:114140. [PMID: 32062096 DOI: 10.1016/j.envpol.2020.114140] [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: 11/06/2019] [Revised: 01/08/2020] [Accepted: 02/05/2020] [Indexed: 06/10/2023]
Abstract
Microbial communities in activated sludge (AS) have a significant influence on the functions and stability of aeration tanks in wastewater treatment plants (WWTPs). The microbial community structure is affected by various factors, among which operational parameters outcompeted as the key factors in shaping its structure. However, as an important operational parameter of aeration tank, the mechanisms by which sludge retention time (SRT) affect community properties remain unclear. In this study, 144 AS samples from aeration tanks of 48 full-scale WWTPs operating under different SRT conditions were examined via high-throughput Illumina-MiSeq sequencing technology. The results indicated that SRT significantly affected the diversity, composition, assembly, and co-occurrence patterns of the microbial community in aeration tanks. Moreover, our results provided clear evidence that the microbial communities in aeration tanks operating under SRT of 10-20 days have the highest biodiversity, the lowest stochastic processes influence, the more stable molecular ecological network structure, the lowest risks of filamentous sludge bulking and enhanced nitrogen removal potential. The microbial communities could be more stable and resilient to disturbance when aeration tanks were operated under this SRT condition. The findings of this study provided a reference for the optimization of aeration tanks from an of microbial community perspective.
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Affiliation(s)
- Chenxiang Sun
- Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, Beijing, 100084, China
| | - Bing Zhang
- Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, Beijing, 100084, China
| | - Zhan Chen
- Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, Beijing, 100084, China
| | - Wentao Qin
- Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, Beijing, 100084, China
| | - Xianghua Wen
- Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, Beijing, 100084, China.
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9
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Amariei G, Boltes K, Rosal R, Leton P. Enzyme response of activated sludge to a mixture of emerging contaminants in continuous exposure. PLoS One 2020; 15:e0227267. [PMID: 31931513 PMCID: PMC6957336 DOI: 10.1371/journal.pone.0227267] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 12/15/2019] [Indexed: 01/07/2023] Open
Abstract
The relevant information about the impacts caused by presence of emerging pollutants in mixtures on the ecological environment, especially on the more vulnerable compartments such as activated sludge (AS) is relatively limited. This study investigated the effect of ibuprofen (IBU) and triclosan (TCS), alone and in combination to the performance and enzymatic activity of AS bacterial community. The assays were carried out in a pilot AS reactor operating for two-weeks under continuous dosage of pollutants. The microbial activity was tracked by measuring oxygen uptake rate, esterase activity, oxidative stress and antioxidant enzyme activities. It was found that IBU and TCS had no acute toxic effects on reactor biomass concentration. TCS led to significant decrease of COD removal efficiency, which dropped from 90% to 35%. Continuous exposure to IBU, TCS and their mixtures increased the activities of glutathione s-transferase (GST) and esterase as a response to oxidative damage. A high increase in GST activity was associated with non-reversible toxic damage while peaks of esterase activity combined with moderate GST increase were attributed to an adaptive response.
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Affiliation(s)
- Georgiana Amariei
- Department of Chemical Engineering, University of Alcalá, Alcalá de Henares, Madrid, Spain
- * E-mail:
| | - Karina Boltes
- Department of Chemical Engineering, University of Alcalá, Alcalá de Henares, Madrid, Spain
| | - Roberto Rosal
- Department of Chemical Engineering, University of Alcalá, Alcalá de Henares, Madrid, Spain
| | - Pedro Leton
- Department of Chemical Engineering, University of Alcalá, Alcalá de Henares, Madrid, Spain
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10
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Fang F, Xu RZ, Huang YQ, Wang SN, Zhang LL, Dong JY, Xie WM, Chen X, Cao JS. Production of polyhydroxyalkanoates and enrichment of associated microbes in bioreactors fed with rice winery wastewater at various organic loading rates. BIORESOURCE TECHNOLOGY 2019; 292:121978. [PMID: 31415988 DOI: 10.1016/j.biortech.2019.121978] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 08/06/2019] [Accepted: 08/07/2019] [Indexed: 06/10/2023]
Abstract
This study aimed to explore the production of polyhydroxyalkanoates (PHA) and selection of PHA-accumulating microorganisms in bioreactors fed with rice winery wastewater at various organic loading rates (OLRs). The substrate utilization, sludge properties, PHA synthesis and microbial community structure of three sequencing batch reactors were monitored. The results show the highest PHA yield (0.23 g/g) was achieved in one of the three reactors with an OLR of 2.4 g COD/L/d, in which Zoogloea was the most dominant PHA-accumulating microorganism. To quantify the PHA production and track the population changing profiles of the PHA-accumulating microorganisms in the long-term reactor operation, the Activated Sludge Model No. 3 was modified with two different heterotrophic microorganisms responding differently with the same substrate. The modeling results indicate that a moderate OLR (>2.4 gCOD/L/d) was beneficial for PHA production. The results are useful for understanding the PHA production from industrial wastewaters and selection of PHA-accumulating microorganisms.
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Affiliation(s)
- Fang Fang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China.
| | - Run-Ze Xu
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Yan-Qiu Huang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Su-Na Wang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Lu-Lu Zhang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Jin-Yun Dong
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
| | - Wen-Ming Xie
- School of Environment, Nanjing Normal University, Nanjing 210046, China
| | - Xueming Chen
- Process and Systems Engineering Center (PROSYS), Department of Chemical and Biochemical Engineering, Technical University of Denmark, 2800 Kgs Lyngby, Denmark
| | - Jia-Shun Cao
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
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11
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Ouyang J, Li C, Zhang G, Wei D, Wei L, Chang CC. Activated sludge and other aerobic suspended culture processes. WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2019; 91:992-1000. [PMID: 31220385 DOI: 10.1002/wer.1164] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 06/12/2019] [Indexed: 06/09/2023]
Abstract
The fields in the process model of activated sludge, the characteristics and species of microbial communities, dynamics and mechanism in the process, the influence of different xenobiotics on activated sludge, anaerobic digestion on waste activated sludge, and design and operation for activated sludge are reviewed in 2018. Contrast with the past reviews, several new highlights such as waste activated sludge treatment, antibiotic and heavy-metal xenobiotic, and pretreatment for anaerobic digestion are mentioned in 2018, which indicated that the research tendency of activated sludge from wastewater treatment to waste sludge treatment in the retrieved literature is developing. PRACTITIONER POINTS: None.
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Affiliation(s)
- Jia Ouyang
- Guangzhou HKUST Fok Ying Tung Research Institute, Guangzhou, China
| | - Chunying Li
- School of Energy and Civil Engineering, Harbin University of Commerce, Harbin, China
| | - Guocai Zhang
- College of Forestry, Northeast Forestry University, Harbin, China
| | - Dong Wei
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, Heilongjiang Province, China
| | - Li Wei
- Guangzhou HKUST Fok Ying Tung Research Institute, Guangzhou, China
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, Heilongjiang Province, China
| | - Chein-Chi Chang
- Department of Engineering and Technical Services, DC Water and Sewer Authority, Washington, District of Columbia, USA
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12
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Li Z, Hang Z, Zhang Q, Zhang S, Zhang T, Yu H. Tuning of activated sludge in winter based on respirogram profiles under standard and site temperatures. J Environ Sci (China) 2019; 79:330-338. [PMID: 30784456 DOI: 10.1016/j.jes.2018.12.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 12/14/2018] [Accepted: 12/17/2018] [Indexed: 06/09/2023]
Abstract
Respirograms of activated sludge OURTx and OUR20x were measured under site (T) and standard (20°C) temperatures, respectively, and the predicted standard temperature respirogram OUR20x,cal was also calculated using the Arrhenius equation. These respirogram profiles reveal more information than effluent quality. A decrease of OUR20x is a critical alarm signal for the loss of pollutant removal capacity, and a sudden increase of the predicted value OUR20x,cal is an alarm signal for the unrecoverable deterioration of biomass. The sign of OUR20x-OUR20x,cal can be used for selection of tuning strategies. For example, a negative value of OUR20x-OUR20x,cal indicates that doubling biomass is difficult, thus strategies such as extending the reaction time with limited available biomass is preferred. The findings in this study elucidated the respiration profile of activated sludge under changes of temperature and can be effectively used for the stable operation of Wastewater Treatment Plants under cold temperatures and seasonal variations.
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Affiliation(s)
- Zhihua Li
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
| | - Zhenyu Hang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Qian Zhang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Shuangshuang Zhang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Tianyu Zhang
- Department of Mathematical Sciences, Montana State University, Bozeman, MT 59717-2400, USA
| | - Hanqing Yu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei 230026, China.
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13
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Ma SJ, Ding LL, Hu HD, Ma HJ, Xu K, Huang H, Geng JJ, Ren HQ. Cell membrane characteristics and microbial population distribution of MBBR and IFAS with different dissolved oxygen concentration. BIORESOURCE TECHNOLOGY 2018; 265:17-24. [PMID: 29864733 DOI: 10.1016/j.biortech.2018.03.111] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/20/2018] [Accepted: 03/23/2018] [Indexed: 06/08/2023]
Abstract
This paper investigated the influences of different dissolved oxygen (DO) concentration (0.71-1.32, 2.13-3.02 and 4.31-5.16 mg/L) on cell membrane characteristics and microbial population distribution of moving biofilm reactors. Two representative reactors, i.e., moving bed biofilm reactors and integrated fixed-film activated sludge were operated. Results indicated that both DO concentration of 0.71-1.32 mg/L and 4.31-5.16 mg/L could increase membrane lipid mobile fraction (49.4%-67.4%) of the microbes, however, through prompting the synthesis of branched fatty acids and unsaturated fatty acids, respectively. For the biofilms, the abundance of Bacteroidetes decreased and Actinobacteria increased with the increase of DO levels. The lowest EfOM content and the highest microbial diversities (1.14-1.52) was observed at DO of 2.13-3.02 mg/L. Redundancy analysis showed that changes of DO levels could alter cell membrane properties and bacterial community structures, and subsequently significantly influenced effluent organic matter composition of moving biofilm reactors.
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Affiliation(s)
- Si-Jia Ma
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Li-Li Ding
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Hai-Dong Hu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Hai-Jun Ma
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Ke Xu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Hui Huang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Jin-Ju Geng
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Hong-Qiang Ren
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China.
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14
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Li ZH, Zhu YM, Yang CJ, Zhang TY, Yu HQ. A simple respirogram-based approach for the management of effluent from an activated sludge system. BIORESOURCE TECHNOLOGY 2018; 261:412-419. [PMID: 29698890 DOI: 10.1016/j.biortech.2018.03.134] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 03/29/2018] [Accepted: 03/30/2018] [Indexed: 06/08/2023]
Abstract
Managing wastewater treatment plant (WWTP) based on respirometric analysis is a new and promising field. In this study, a multi-dimensional respirogram space was constructed, and an important index Res/t (ratio of in-situ respiration rate to maximum respiration rate) was derived as an alarm signal for the effluent quality control. A smaller Res/t value suggests better effluent. The critical R'es/t value used for determining whether the effluent meets the regulation depends on operational conditions, which were characterized by temperature and biomass ratio of heterotrophs to autotrophs. With given operational conditions, the critical R'es/t value can be calculated from the respirogram space and effluent conditions required by the discharge regulation, with no requirement for calibration of parameters or any additional measurements. Since it is simple, easy to use, and can be readily implemented online, this approach holds a great promise for applications.
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Affiliation(s)
- Zhi-Hua Li
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
| | - Yuan-Mo Zhu
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Cheng-Jian Yang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Tian-Yu Zhang
- Department of Mathematical Sciences, Montana State University, Bozeman, MT 59717-2400, USA
| | - Han-Qing Yu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei 230026, China
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