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Liu C, Li L, Xu L, Zhang T, He Q, Xin X. Enhancing volatile fatty acids production from waste activated sludge: The role of pretreatment by N,N-bis(carboxymethyl)-l-glutamate (GLDA). ENVIRONMENTAL SCIENCE AND ECOTECHNOLOGY 2024; 21:100393. [PMID: 38357479 PMCID: PMC10864876 DOI: 10.1016/j.ese.2024.100393] [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: 07/02/2023] [Revised: 01/16/2024] [Accepted: 01/19/2024] [Indexed: 02/16/2024]
Abstract
N,N-bis(carboxymethyl)-l-glutamate (GLDA) is an eco-friendly chelating agent that effectively extracts multivalent metal ions from waste activated sludge (WAS) flocs, which could potentially alter their structure. However, the effect of GLDA on the production of volatile fatty acids (VFAs) from WAS is not well known. Here, we demonstrate that pretreatment with GLDA at a concentration of 200 mmol per kg VSS results in a significant increase of 142% in extractable extracellular polymeric substances and enhances the total VFAs yield by 64% compared to untreated samples. We reveal GLDA's capability to mobilize organic-binding multivalent metal ions within sludge flocs. Specifically, post-pretreatment analyses showed the release of 69.1 mg L-1 of Ca and 109.8 mg L-1 of Fe ions from the flocs, leading to a more relaxed floc structure and a reduced apparent activation energy (10.6 versus 20 kJ mol-1) for WAS solubilization. Molecular dynamic simulations further demonstrate GLDA's preferential binding to Fe3+ and Ca2+ over Mg2+. Our study suggests that GLDA pretreatment causes minimal disruption to reactor stability, thereby indicating the stability of microbial community composition. GLDA has emerged as a viable pretreatment agent for enhancing volatile fatty acids production from waste activated sludge.
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Affiliation(s)
- Chang Liu
- Key Laboratory of the Three Gorges Reservoir Region's Eco-environment, Ministry of Education, College of Environment and Ecology, Chongqing University, Chongqing, 400045, PR China
| | - Lin Li
- Key Laboratory of the Three Gorges Reservoir Region's Eco-environment, Ministry of Education, College of Environment and Ecology, Chongqing University, Chongqing, 400045, PR China
| | - Linji Xu
- Key Laboratory of the Three Gorges Reservoir Region's Eco-environment, Ministry of Education, College of Environment and Ecology, Chongqing University, Chongqing, 400045, PR China
| | - Tanglong Zhang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-environment, Ministry of Education, College of Environment and Ecology, Chongqing University, Chongqing, 400045, PR China
| | - Qiang He
- Key Laboratory of the Three Gorges Reservoir Region's Eco-environment, Ministry of Education, College of Environment and Ecology, Chongqing University, Chongqing, 400045, PR China
| | - Xiaodong Xin
- Research Center for Eco-Environmental Engineering, Dongguan University of Technology, Dongguan, 523808, PR China
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2
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Cai S, Zhang X, Chen S, Peng S, Sun T, Zhang Y, Yang P, Chai H, Wang D, Zhang W. Solid-liquid redistribution and degradation of antibiotics during hydrothermal treatment of sewage sludge: Interaction between biopolymers and antibiotics. WATER RESEARCH 2024; 258:121759. [PMID: 38754299 DOI: 10.1016/j.watres.2024.121759] [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: 02/02/2024] [Revised: 04/24/2024] [Accepted: 05/08/2024] [Indexed: 05/18/2024]
Abstract
Waste activated sludge serves an important reservoir for antibiotics within wastewater treatment plants, and understanding the occurrence and evolution of antibiotics during sludge treatment is crucial to mitigate the potential risks of subsequent resource utilization of sludge. This study explores the degradation and transformation mechanisms of three typical antibiotics, oxytetracycline (OTC), ofloxacin (OFL), and azithromycin (AZI) during sludge hydrothermal treatment (HT), and investigates the influence of biopolymers transformation on the fate of these antibiotics. The findings indicate that HT induces a shift of antibiotics from solid-phase adsorption to liquid-phase dissolution in the initial temperature range of 25-90 °C, underscoring this phase's critical role in preparing antibiotics for subsequent degradation phases. Proteins (PN) and humic acids emerge as crucial for antibiotic binding, facilitating their redistribution within sludge. Specifically, the binding capacity sequence of biopolymers to antibiotics is as follows: OFL>OTC>AZI, highlighting that OFL-biopolymers display stronger electrostatic attraction, more available adsorption sites, and more stable binding strength. Furthermore, antibiotic degradation mainly occurs above 90 °C, with AZI being the most temperature-sensitive, degrading 92.97% at 180 °C, followed by OTC (91.26%) and OFL (52.51%). Concurrently, the degradation products of biopolymers compete for active sites to form novel amino acid-antibiotic conjugates, which inhibits the further degradation of antibiotics. These findings illuminate the effects of biopolymers evolution on intricate dynamics of antibiotics fate in sludge HT and are helpful to optimize the sludge HT process for effective antibiotics abatement.
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Affiliation(s)
- Siying Cai
- School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China
| | - Xinyu Zhang
- School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China
| | - Shuaiyu Chen
- School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China
| | - Sainan Peng
- School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China
| | - Tong Sun
- School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China
| | - Yu Zhang
- School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China
| | - Peng Yang
- School of Civil Engineering and Architecture, Northeast Electric Power University, Jilin 132012, Jilin, China
| | - Hongxiang Chai
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Environment and Ecology, Chongqing University, Chongqing 400045, China
| | - Dongsheng Wang
- Department of environmental engineering, Zhejiang University, Hangzhou 310058, Zhejiang, China
| | - Weijun Zhang
- School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China; National Engineering Research Center of Industrial Wastewater Detoxication and Resource Recovery, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
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3
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Tan Y, Xiao Y, Hao T. Carbon fixation via volatile fatty acids recovery from sewage sludge through electrochemical-pretreatment-based anaerobic digestion. WATER RESEARCH 2024; 258:121736. [PMID: 38754300 DOI: 10.1016/j.watres.2024.121736] [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: 03/12/2024] [Revised: 04/30/2024] [Accepted: 05/03/2024] [Indexed: 05/18/2024]
Abstract
Capturing the carbon in volatile fatty acids (VFA) produced from the anaerobic digestion (AD) of sewage sludge has the potential to not only provide economic benefits but also reduce greenhouse gas production. This study demonstrates a chemical-free method to collect VFA from an AD instead of methane that involves electrochemical pretreatment (EPT) of sludge. Experimental results show that applying 15 V EPT for 45 min enhances acidogenesis and selectively inhibits methanogenesis, leading to a substantial VFA accumulation (2563.1 ± 307.9 mg COD/L) and achieving 2.5 times more carbon fixation than via methane production. Interfacial thermodynamic analysis shows that EPT induces a decrease in both the repulsive electrostatic energy (from 152.9 kT to 12.2 kT) and the energy barrier (from 57.0 kT to 2.6 kT) in the sludge, leading to increased sludge aggregation and entrapment of microorganisms. Molecular docking sheds lights on how the methanogens interacts with the organic matter released from EPT (e.g., alanine-tRNA ligase), showing that these interactions potentially interfere with the proteins that are associated with the activities of the methanogens and the electron transfer pathways, thereby impeding methanogenesis. Integrating EPT into AD therefore facilitates the recovery of valuable VFA and the capture of carbon from freshwater sludge, providing notable economic and environmental benefits in sewage sludge treatment.
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Affiliation(s)
- Yunkai Tan
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau, PR China
| | - Yihang Xiao
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau, PR China
| | - Tianwei Hao
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau, PR China.
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Wang L, Lei Z, Zhang Z, Yang X, Chen R. Deciphering the role of extracellular polymeric substances in the adsorption and biotransformation of organic micropollutants during anaerobic wastewater treatment. WATER RESEARCH 2024; 257:121718. [PMID: 38723358 DOI: 10.1016/j.watres.2024.121718] [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: 02/28/2024] [Revised: 04/20/2024] [Accepted: 05/02/2024] [Indexed: 05/29/2024]
Abstract
Extracellular polymeric substances (EPS) participate in the removal of organic micropollutants (OMPs), but the primary pathways of removal and detailed mechanisms remain elusive. We evaluated the effect of EPS on removal for 16 distinct chemical classes of OMPs during anaerobic digestion (AD). The results showed that hydrophobic OMPs (HBOMPs) could not be removed by EPS, while hydrophilic OMPs (HLOMPs) were amenable to removal via adsorption and biotransformation of EPS. The adsorption and biotransformation of HLOMPs by EPS accounted up to 19.4 ± 0.9 % and 6.0 ± 0.8 % of total removal, respectively. Further investigations into the adsorption and biotransformation mechanisms of HLOMPs by EPS were conducted utilizing spectral, molecular dynamics simulation, and electrochemical analysis. The results suggested that EPS provided abundant binding sites for the adsorption of HLOMPs. The binding of HLOMPs to tryptophan-like proteins in EPS formed nonfluorescent complexes. Hydrogen bonds, hydrophobic interactions and water bridges were key to the binding processes and helped stabilize the complexes. The biotransformation of HLOMPs by EPS may be attributed to the presence of extracellular redox active components (c-type cytochromes (c-Cyts), c-Cyts-bound flavins). This study enhanced the comprehension for the role of EPS on the OMPs removal in anaerobic wastewater treatment.
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Affiliation(s)
- Lianxu Wang
- Key Lab of Environmental Engineering, Shaanxi Province, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China
| | - Zhen Lei
- Key Lab of Environmental Engineering, Shaanxi Province, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China
| | - Zixin Zhang
- Key Lab of Environmental Engineering, Shaanxi Province, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China
| | - Xiaohuan Yang
- Key Lab of Environmental Engineering, Shaanxi Province, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China
| | - Rong Chen
- Key Lab of Environmental Engineering, Shaanxi Province, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China; International S&T Cooperation Center for Urban Alternative Water Resources Development, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China.
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Li Y, Ke S, Xu D, Zhuo H, Liu X, Gao B. Preferential deposition of buoyant small microplastics in surface sediments of the Three Gorges Reservoir, China: Insights from biomineralization. JOURNAL OF HAZARDOUS MATERIALS 2024; 468:133693. [PMID: 38367432 DOI: 10.1016/j.jhazmat.2024.133693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/25/2024] [Accepted: 01/31/2024] [Indexed: 02/19/2024]
Abstract
Sediments act as sinks of microplastics (MPs) derived from terrestrial ecosystems. However, the fate and transport of MPs at the zone of sediment-overlying water in reservoir environment are poorly understood. Here, the MPs distribution patterns in surface sediments of the Three Gorges Reservoir (TGR) and dominant mechanisms responsible for the sinking of MPs at the zone of sediment-overlying water were comprehensively investigated. The predominant occurrence of small microplastics (<300 µm, SMPs) in surface sediments of the TGR was found, with buoyant polyethene (PE) was dominant polymer types. Interestingly, the high abundance of SMPs in sediments correlated well with the Ca2+/Mg2+ in overlying water, suggesting that divalent cations in overlying water may enhance the preferential deposition of SMPs. Simulation sinking experiments under the presence of Microcystis aeruginosa and two divalent cations using different-sized PE MPs demonstrated that the greater deposition of SMPs was mainly the result of the formation of biogenic calcite on the surface of MPs rather than magnesium minerals, which provides stronger ballasting effects for SMPs than for large MPs. This study first highlights that the impact of biomineralization on preferential sinking of SMPs and enhances the understanding of the transport behaviour of MPs in aquatic environment.
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Affiliation(s)
- Yang Li
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China; State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing 100038, China
| | - Sun Ke
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Dongyu Xu
- State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing 100038, China
| | - Haihua Zhuo
- Changjiang Basin Ecology and Environment Monitoring and Scientific Research Center, Changjiang Basin Ecology and Environment Administration, Ministry of Ecology and Environment, Wuhan 430010, China
| | - Xiaobo Liu
- State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing 100038, China
| | - Bo Gao
- State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing 100038, China.
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Priyadarshanee M, Das S. Spectra metrology for interaction of heavy metals with extracellular polymeric substances (EPS) of Pseudomonas aeruginosa OMCS-1 reveals static quenching and complexation dynamics of EPS with heavy metals. JOURNAL OF HAZARDOUS MATERIALS 2024; 466:133617. [PMID: 38306836 DOI: 10.1016/j.jhazmat.2024.133617] [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: 10/13/2023] [Revised: 01/08/2024] [Accepted: 01/23/2024] [Indexed: 02/04/2024]
Abstract
The adsorption behavior and interaction mechanisms of extracellular polymeric substances (EPS) of Pseudomonas aeruginosa OMCS-1 towards chromium (Cr), lead (Pb), and cadmium (Cd) were investigated. EPS-covered (EPS-C) cells exhibited significantly higher (p < 0.0001; two-way ANOVA) removal of Cr (85.58 ± 0.39%), Pb (81.98 ± 1.02%), and Cd (73.88 ± 1%) than EPS-removed (EPS-R) cells. Interactions between EPS-heavy metals were spontaneous (ΔG<0). EPS-Cr(VI) and EPS-Pb(II) binding were exothermic (ΔH<0), while EPS-Cd(II) binding was endothermic (ΔH>0) process. EPS bonded to Pb(II) via inner-sphere complexation by displacement of surrounding water molecules, while EPS-Cr(VI) and EPS-Cd(II) binding occurred through outer-sphere complexation via electrostatic interactions. Increased zeta potential of Cr (29.75%), Pb (41.46%), and Cd (46.83%) treated EPS and unchanged crystallinity (CIXRD=0.13), inferred EPS-metal binding via both electrostatic interactions and complexation mechanism. EPS-metal interaction was predominantly promoted through hydroxyl, amide, carboxyl, and phosphate groups. Metal adsorption deviated EPS protein secondary structures. Strong static quenching mechanism between tryptophan protein-like substances in EPS and heavy metals was evidenced. EPS sequestered heavy metals via complexation with C-O, C-OH, CO/O-C-O, and NH/NH2 groups and ion exchange with -COOH group. This study unveils the fate of Cr, Pb, and Cd on EPS surface and provides insight into the interactions among EPS and metal ions for metal sequestration.
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Affiliation(s)
- Monika Priyadarshanee
- Laboratory of Environmental Microbiology and Ecology (LEnME), Department of Life Science, National Institute of Technology, Rourkela 769 008, Odisha, India
| | - Surajit Das
- Laboratory of Environmental Microbiology and Ecology (LEnME), Department of Life Science, National Institute of Technology, Rourkela 769 008, Odisha, India.
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7
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Lv Y, Kuang J, Ding Z, Li R, Shi Z. Soil moisture dynamics regulates the release rates and lability of copper in contaminated paddy soils. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 908:168525. [PMID: 37967635 DOI: 10.1016/j.scitotenv.2023.168525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 11/09/2023] [Accepted: 11/10/2023] [Indexed: 11/17/2023]
Abstract
The climate changes have caused more extreme precipitation and drought events in the field and have exacerbated the severity of wet-dry events in soils, which will inevitably lead to severe fluctuations in soil moisture content. Soil moisture content has been recognized to influence the distribution of heavy metals, but how temporal changes of soil moisture dynamics affect the release rates and lability of heavy metals is still poorly understood, which precludes accurate prediction of environmental behavior and environmental risk of heavy metals in the field. In this study, we combined experimental and modeling approaches to quantify copper release rates and labile copper fractions in two paddy soils from southern China under different moisture conditions. Our kinetic data and models showed that the release rates and lability of copper were highly associated with the soil moisture contents, in which, surprisingly, high soil moisture contents effectively reduced the release rates of copper even with little changes in the reactive portions of copper in soils. A suite of comprehensive characterization on soil solid and solution components along the incubation suggested that soil microbes may regulate soil copper lability through forming microbially derived organic matter that sequestered copper and by increasing soil particle aggregation for protecting copper from release. This study highlights the importance of incorporating soil moisture dynamics into future environmental models. The experimental and modeling approaches in this study have provided basis for further developing predictive models applicable to paddy soils with varying soil moisture under the impact of climate change.
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Affiliation(s)
- Yijin Lv
- The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, People's Republic of China
| | - Jialiang Kuang
- The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, People's Republic of China
| | - Zecong Ding
- The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, People's Republic of China
| | - Rong Li
- The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, People's Republic of China
| | - Zhenqing Shi
- The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, People's Republic of China.
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Peng S, Wang Z, Li L, Ai J, Li L, Liao G, Wang D, Peng S, Zhang W. Molecular dynamic modeling of EPS and inorganic/organic flocculants during sludge dual conditioning. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167719. [PMID: 37838038 DOI: 10.1016/j.scitotenv.2023.167719] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 10/08/2023] [Accepted: 10/08/2023] [Indexed: 10/16/2023]
Abstract
Extracellular polymeric substances (EPS) are the key components determining the dewatering behavior of wastewater sludge. However, current technical optimization of sludge conditioning for dewatering is limited by the poor understanding of the conditioner-EPS interactions at molecular levels. Herein, a combination of molecular dynamic (MD) simulations, dewaterability assessment and EPS characterization was used to reveal the sludge dewatering mechanisms using dual conditioning processes (prevalent inorganic (poly aluminum chloride (PAC)) and organic (poly dimethyl diallyl ammonium chloride (PDDA)). Results suggested that PAC and PDDA bridged the biopolymers mainly through electrostatic interactions, promoting the agglomeration of biopolymers and reducing their contact probability with water molecules. Water molecules were tightly bound to EPS mainly through hydrogen bonding with polar oxygen-containing functional groups. The adsorption of PAC and PDDA on hydrophilic components reduced the molecular polarity of biopolymers and altered the conformation of water molecules in the hydration shell, resulting in a decreased hydration capacity of EPS and the release of bound water, and sludge dewaterability was improved. PAC was found to be more effective than PDDA in disrupting the hydrogen bonding between water molecules and EPS, especially the protein β-sheet structure inside the molecular clusters with its high charge strength and diffusivity. Sludge bound water decreased by 73.16 % after PAC conditioning. In addition, PDDA exhibited superior agglomeration ability to biopolymers and promoted the electrostatic interaction between PAC and polar groups during dual conditioning. The strength and hydrophobicity of EPS molecular clusters were thus enhanced, and the conditioning efficiency was improved. This study offers molecular-level insights into the coagulation treatment process of sludge and provides theoretical references for process optimization and new conditioner development.
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Affiliation(s)
- Sainan Peng
- Faculty Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, Hubei, China
| | - Zhiyue Wang
- Department of Civil and Environmental Engineering, University of Hawai'i at Mānoa, USA, Honolulu, HI 96822-2217, USA; Water Resources Research Center, University of Hawai'i at Mānoa, USA, Honolulu, HI 96822-2217, USA.
| | - Linyu Li
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China
| | - Jing Ai
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China
| | - Lanfeng Li
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China
| | - Guiying Liao
- Faculty Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, Hubei, China
| | - Dongsheng Wang
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, Zhejiang, China
| | - Siwei Peng
- Datang Environment Industry Group Co., Ltd, Haidian District, Beijing 100097, China
| | - Weijun Zhang
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China; National Engineering Research Center of Industrial Wastewater Detoxication and Resource Recovery, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
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Huang W, Li Y, Wang F, Feng L, Wang D, Ma Y, Wu Y, Luo J. Disinfectant sodium dichloroisocyanurate synergistically strengthened sludge acidogenic process and pathogens inactivation: Targeted upregulation of functional microorganisms and metabolic traits via self-adaptation. WATER RESEARCH 2023; 247:120787. [PMID: 37918196 DOI: 10.1016/j.watres.2023.120787] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 10/18/2023] [Accepted: 10/26/2023] [Indexed: 11/04/2023]
Abstract
Harmless and resourceful treatment of waste activated sludge (WAS) have been the crucial goal for building environmental-friendly and sustainable society, while the synergistic realization approach is currently limited. This work skillfully utilized the disinfectant sodium dichloroisocyanurate (NaDCC) to simultaneously achieve the pathogenic potential inactivation (decreased by 60.1 %) and efficient volatile fatty acids (VFAs) recovery (increased by 221.9 %) during WAS anaerobic fermentation in rather cost-effective way (Chemicals costs:0.4 USD/kg VFAs versus products benefits: 2.68 USD/kg chemical). Mechanistic analysis revealed that the C=O and NCl bonds in NaDCC could spontaneously absorb sludge (binding energy -4.9 kJ/mol), and then caused the sludge disintegration and organic substrates release for microbial utilization due to the oxidizability of NaDCC. The disruption of sludge structure along with the increase of bioavailable fermentation substrates contributed to the selectively regulation of microbial community via enriching VFAs-forming microorganisms (e.g., Pseudomonas and Streptomyces) and reducing VFAs-consuming microorganisms, especially aceticlastic methanogens (e.g., Methanothrix and Methanospirillum). Correspondingly, the metabolic functions of membrane transport, substrate metabolism, pyruvate metabolism, and fatty acid biosynthesis locating in the central pathway of VFAs production were all upregulated while the methanogenic step was inhibited (especially acetate-type methanogenic pathway). Further exploration unveiled that for those enriched functional anaerobes were capable to activate the self-adaptive systems of DNA replication, SOS response, oxidative stress defense, efflux pump, and energy metabolism to counteract the unfavorable NaDCC stress and maintain high microbial activities for efficient VFAs yields. This study would provide a novel strategy for synergistic realization of harmless and resourceful treatment of WAS, and identify the interrelations between microbial metabolic regulations and adaptive responses.
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Affiliation(s)
- Wenxuan Huang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, China; College of Environment, Hohai University, Nanjing 210098, China
| | - Yi Li
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, China; College of Environment, Hohai University, Nanjing 210098, China
| | - Feng Wang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, China; College of Environment, Hohai University, Nanjing 210098, China
| | - Leiyu Feng
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Dongbo Wang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China
| | - Yingqun Ma
- Shaanxi Key Laboratory of Energy Chemical Process Intensification, School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Yang Wu
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
| | - Jingyang Luo
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, China; College of Environment, Hohai University, Nanjing 210098, China.
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10
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Han Z, Wang Y, Zhang D, Fan X, Zhang S, Liu M. Free nitrous acid-assisted asymmetrical alternating current electrochemistry (FNA-AACE) for multi-heavy metals decontamination in waste activated sludge. WATER RESEARCH 2023; 242:120259. [PMID: 37390660 DOI: 10.1016/j.watres.2023.120259] [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: 03/09/2023] [Revised: 06/18/2023] [Accepted: 06/21/2023] [Indexed: 07/02/2023]
Abstract
Heavy metal contamination of waste activated sludge (WAS) is a key factor limiting the land application of sludge for nutrients recovery. This study proposes a novel free nitrous acid (FNA)-assisted asymmetrical alternating current electrochemistry (FNA-AACE) process to achieve high-efficiency decontamination of multi-heavy metals (Cd, Pb, and Fe) in WAS. The optimal operating conditions, the heavy metal removal performance of FNA-AACE, and the related mechanisms for maintaining the high performance were systematically investigated. During the FNA-AACE process, FNA treatment was optimal with an exposure time of 13 h at a pH of 2.9 and an FNA concentration of 0.6 mg/g TSS. Then the sludge was washed with EDTA in a recirculating leaching system under asymmetrical alternating current electrochemistry (AACE). The 6-h working and the following electrode cleaning were defined as a working circle of AACE. After three cycles of working-cleaning periods in AACE treatment, the cumulative removal efficiency of the toxic metals Cd and Pb reached over 97% and 93%, respectively, whilst that of Fe was greater than 65%. This surpasses most previously reported efficiencies and possesses a shorter treatment duration and sustainable EDTA circulation. The mechanism analysis suggested that FNA pretreatment provoked the migration of heavy metals for leaching enhancement, as well as reduced the demand for EDTA eluent concentration and increased conductivity, which can improve the AACE efficiency. Meanwhile, the AACE process absorbed the anionic chelates of heavy metals and reduced them to zero-valent particles on the electrode, regenerating the EDTA eluent and maintaining its high extraction efficiency for heavy metals. In addition, FNA-AACE could provide different electric field operation modes, allowing it to have flexibility for the real application processes. This proposed process is expected to be coupled with anaerobic digestion in wastewater treatment plants (WWTPs) for high efficiency of heavy metal decontamination, sludge reduction, and resource/energy recovery.
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Affiliation(s)
- Zhibo Han
- Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Yili Wang
- Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China.
| | - Daxin Zhang
- Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China; School of Soil & Water Conservation, Beijing Forestry University, Beijing, 100083, China.
| | - Xiaoyang Fan
- Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Shuting Zhang
- Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Meilin Liu
- Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
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