1
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Chi B, Huang Y, Xiong Z, Tan J, Zhou W, Yang Z, Zhou K, Duan X, Chen A, Zha R, Gui K. Investigation of lysing excess sludge slurry using hydrolase secreting thermophilic bacterial communities. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 349:119562. [PMID: 37952379 DOI: 10.1016/j.jenvman.2023.119562] [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: 05/12/2023] [Revised: 10/22/2023] [Accepted: 11/04/2023] [Indexed: 11/14/2023]
Abstract
Sludge reduction is a critical challenge in biological wastewater treatment. Combining excess sludge slurry lysis technology with traditional activated sludge processes is a promising approach for in-situ sludge reduction. Here, a strategy for excess sludge slurry lysis based on thermophilic bacterial communities (LTBC) was proposed. This investigation focused on the process of excess sludge slurry lysis dominated by thermophilic bacterial communities domesticated at different temperatures (55-75 °C). The evolution of sludge lysate was analyzed, and the mechanism of excess sludge slurry lysis under the action of thermophilic bacterial communities was elucidated through amplicon sequencing analysis. The results demonstrated that the aerobic thermophilic bacterial communities adapted to 75 °C exhibit the highest efficiency in sludge slurry lysis. During LTBC process, the removal efficiency of volatile suspended solids reached 53.9 ± 1.8% within 2 h, and 97.0 ± 1.0% of the protein and 96.0 ± 1.0% of the polysaccharide in the extracellular polymers was solubilized, and bacterial cell walls in sludge were disrupted. Fourier transform infrared spectroscopy and excitation-emission matrix spectroscopy of the sludge lysate demonstrated that the LTBC process was accompanied by humification process. The accumulation of humic acid primarily occurred at 55 °C and 65 °C, while fulvic acid occurred at 75 °C. The thermophilic bacterial communities adapted to 75 °C were dominated by Thermus and Thermaerobacter. Phylogenetic studies showed that the LTBC hydrolase system comprises enzymes related to protein hydrolysis, carbohydrate hydrolysis, and peptidoglycan hydrolysis, including metalopeptidase MepB, neutral α-glucosidase C, N-acetyl Muramyl-L-alanine amidase, and others enzymes. These results provide a theoretical basis for the application of LTBC technology in the reduction of sludge which generated in traditional waste water activated sludge processes.
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Affiliation(s)
- Baoyan Chi
- Solid Waste Treatment and Resource Recycle Research Laboratory, Department of Environmental Science and Technology, School of Energy and Environment, Southeast University, Nanjing, 210096, PR China; Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, Southeast University, Nanjing, 210096, PR China
| | - Ying Huang
- Solid Waste Treatment and Resource Recycle Research Laboratory, Department of Environmental Science and Technology, School of Energy and Environment, Southeast University, Nanjing, 210096, PR China; Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, Southeast University, Nanjing, 210096, PR China.
| | - Zhenfeng Xiong
- Solid Waste Treatment and Resource Recycle Research Laboratory, Department of Environmental Science and Technology, School of Energy and Environment, Southeast University, Nanjing, 210096, PR China; Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, Southeast University, Nanjing, 210096, PR China
| | - Jiali Tan
- Solid Waste Treatment and Resource Recycle Research Laboratory, Department of Environmental Science and Technology, School of Energy and Environment, Southeast University, Nanjing, 210096, PR China; Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, Southeast University, Nanjing, 210096, PR China
| | - Weidong Zhou
- Nanjing Water Group Co., Ltd., Nanjing, 210002, PR China
| | - Zhuo Yang
- Central & South China Municipal Engineering Design and Research Institute Co., Ltd., Wuhan, 430010, PR China
| | - Kemei Zhou
- Nanjing Water Group Co., Ltd., Nanjing, 210002, PR China
| | - Xinxin Duan
- Solid Waste Treatment and Resource Recycle Research Laboratory, Department of Environmental Science and Technology, School of Energy and Environment, Southeast University, Nanjing, 210096, PR China
| | - Ao Chen
- Solid Waste Treatment and Resource Recycle Research Laboratory, Department of Environmental Science and Technology, School of Energy and Environment, Southeast University, Nanjing, 210096, PR China
| | - Rong Zha
- Zhenjiang Esther Environment Protection Technology Co., Ltd., Jurong City, 212400, PR China
| | - Keting Gui
- Solid Waste Treatment and Resource Recycle Research Laboratory, Department of Environmental Science and Technology, School of Energy and Environment, Southeast University, Nanjing, 210096, PR China
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2
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Lu X, Oehmen A, Zhao J, Duan H, Yuan Z, Ye L. Insights on biological phosphorus removal with partial nitrification in single sludge system via sidestream free ammonia and free nitrous acid dosing. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 895:165174. [PMID: 37385509 DOI: 10.1016/j.scitotenv.2023.165174] [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: 03/14/2023] [Revised: 06/10/2023] [Accepted: 06/25/2023] [Indexed: 07/01/2023]
Abstract
The sidestream sludge treatment by free ammonium (FA)/free nitrous acid (FNA) dosing was frequently demonstrated to maintain the nitrite pathway for the partial nitrification (PN) process. Nevertheless, the inhibitory effect of FA and FNA would severely influence polyphosphate accumulating organisms (PAOs), destroying the microbe-based phosphorus (P) removal. Therefore, a strategic evaluation was proposed to successfully achieve biological P removal with a partial nitrification process in a single sludge system by sidestream FA and FNA dosing. Through the long-term operation of 500 days, excellent phosphorus, ammonium and total nitrogen removal performance were achieved at 97.5 ± 2.6 %, 99.1 ± 1.0 % and 75.5 ± 0.4 %, respectively. Stable partial nitrification with a nitrite accumulation ratio (NAR) of 94.1 ± 3.4 was attained. The batch tests also reported the robust aerobic phosphorus uptake based on FA and FNA adapted sludge after exposure of FA and FNA, respectively, suggesting the FA and FNA treatment strategy could potentially offer the opportunity for the selection of PAOs, which synchronously have the tolerance to FA and FNA. Microbial community analysis suggested that Accumulibacter, Tetrasphaera, and Comamonadaceae collectively contributed to the phosphorus removal in this system. Summarily, the proposed work presents a novel and feasible strategy to integrate enhanced biological phosphorus removal (EBPR) and short-cut nitrogen cycling and bring the combined mainstream phosphorus removal and partial nitrification process closer to practical application.
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Affiliation(s)
- Xuanyu Lu
- School of Chemical Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia; Australia Centre for Water and Environmental Biotechnology, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Adrian Oehmen
- School of Chemical Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Jing Zhao
- Sustainable minerals institute, the university of Queensland, St. Lucia, QLD 4072, Australia
| | - Haoran Duan
- School of Chemical Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia; Australia Centre for Water and Environmental Biotechnology, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Zhiguo Yuan
- Australia Centre for Water and Environmental Biotechnology, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Liu Ye
- School of Chemical Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia.
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3
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Li J, Cai L, Lu H, Ma B, Chen G, Kong D, Hu Y, Ye Z, Ruan Y. Effects of Ion Combinations and Their Concentrations on Denitrification Performance and Gene Expressions of an Aerobic Strain Marinobacter Hydrocarbonoclasticus RAD-2. Microorganisms 2023; 11:1867. [PMID: 37630427 PMCID: PMC10456938 DOI: 10.3390/microorganisms11081867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 07/17/2023] [Accepted: 07/18/2023] [Indexed: 08/27/2023] Open
Abstract
Salinity is one of the most important factors affecting the nitrogen-removal efficiency of denitrifying bacteria. A series of different ion combinations and salinity gradients were carried out to clarify the effects of ion types and concentrations on nitrogen removal by halophilic aerobic denitrifying bacteria RAD-2. Nitrate concentrations, nitrite concentrations, TAN concentrations, and OD600 were monitored to investigate their effects on denitrification in each group. The results showed that Na+, K+, and Cl- accelerated the denitrification process and improved nitrogen-removal efficiency at moderate additions, while Ca2+ and Mg2+ showed no significant effect. Na+ was effective alone, while K+ or Cl- needed to be combined with at least one of Na+, K+, or Cl- to achieve similar efficiency. The batch tests of salinity confirmed that the addition of a moderate concentration of NaCl/Na2SO4 could effectively improve nitrogen-removal efficiency, while excessive salinity might hinder denitrification metabolism. In the salinity range of 5~40‱, a 5‱ dosage might be the most economical method for strain RAD-2. Real-time PCR experiments on 17 key nitrogen metabolism-related genes revealed that chloride was widely involved in the nitrogen and carbon metabolism of microorganisms by altering cell osmotic pressure and opening ion channel proteins, thereby affecting the efficiency of denitrification. The results of this study may contribute to a better understanding of the different roles of various ions in aerobic denitrification and highlight the importance of salinity control in highly salted wastewater treatment.
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Affiliation(s)
- Junchi Li
- Institute of Agricultural Bio-Environmental Engineering, College of Bio-Systems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China; (J.L.); (Y.H.)
- The Rural Development Academy, Zhejiang University, Hangzhou 310058, China;
| | - Lei Cai
- Laboratory of Microbial Resources, College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310035, China;
| | - Huifeng Lu
- Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China;
| | - Bin Ma
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China;
| | - Guangsuo Chen
- The Rural Development Academy, Zhejiang University, Hangzhou 310058, China;
| | - Dedong Kong
- Institute of Digital Agriculture, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China; (D.K.); (Z.Y.)
| | - Yiming Hu
- Institute of Agricultural Bio-Environmental Engineering, College of Bio-Systems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China; (J.L.); (Y.H.)
- The Rural Development Academy, Zhejiang University, Hangzhou 310058, China;
| | - Ziran Ye
- Institute of Digital Agriculture, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China; (D.K.); (Z.Y.)
| | - Yunjie Ruan
- Institute of Agricultural Bio-Environmental Engineering, College of Bio-Systems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China; (J.L.); (Y.H.)
- The Rural Development Academy, Zhejiang University, Hangzhou 310058, China;
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4
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Yue X, Liu H, Wei H, Chang L, Gong Z, Zheng L, Yin F. Reactive and microbial inhibitory mechanisms depicting the panoramic view of pH stress effect on common biological nitrification. WATER RESEARCH 2023; 231:119660. [PMID: 36716566 DOI: 10.1016/j.watres.2023.119660] [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: 10/09/2022] [Revised: 01/03/2023] [Accepted: 01/22/2023] [Indexed: 06/18/2023]
Abstract
pH is a crucial factor of microbial nitrification, which often combines with high-strength ammonium to influence nitrogen removal pathway in wastewater treatment. However, the detailed inhibitory mechanisms of pH stress are not sufficiently disclosed yet. In this study, the pH stress effect on nitrification was comprehensively studied by a set of experiments which identified the reactivity of nitrification processes and activity of nitrifiers, the time dependence of inhibition effect and the hybrid pH stress effect with ammonium. The results revealed two distinct inhibitory mechanisms dominating in alkaline and acid ranges. In alkaline range (pH > 8), pH stress causes physiological damages on microorganisms which is named as microbial inhibition. It has the features of less recoverability of nitrifiers, time-dependent inhibition effect and low pH-tolerance of nitrite oxidation bacteria. Free ammonia enhanced microbial inhibition and greatly promoted nitrite accumulation. A novel reactive inhibition mechanism dominated in acid range (pH < 7) was disclosed. It only impedes ammonia oxidation process (AOP) but not impair microbial activity obviously and the effect is time-independent. The mechanism was clarified from H+ transport because AOP involved H+ production. The H+ transport was impeded under acid stress owing to the decrease of pH gradient across cell membrane. The two mechanisms formed a panoramic view of pH stress effect on nitrification advancing the understanding of nitrifier adaptability and nitritation regulation in wastewater treatment processes.
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Affiliation(s)
- Xuehai Yue
- Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu 611756, China
| | - Hong Liu
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - Haotian Wei
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - Lin Chang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - Zhengjun Gong
- Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu 611756, China
| | - Lei Zheng
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - Fengjun Yin
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China.
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5
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Lu X, Wang Z, Duan H, Wu Z, Hu S, Ye L, Yuan Z, Zheng M. Significant production of nitric oxide by aerobic nitrite reduction at acidic pH. WATER RESEARCH 2023; 230:119542. [PMID: 36603308 DOI: 10.1016/j.watres.2022.119542] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 12/20/2022] [Accepted: 12/27/2022] [Indexed: 06/17/2023]
Abstract
The acidic (i.e., pH ∼5) activated sludge process is attracting attention because it enables stable nitrite accumulation and enhances sludge reduction and stabilization, compared to the conventional process at neutral pH. Here, this study examined the production and potential pathways of nitric oxide (NO) and nitrous oxide (N2O) during acidic sludge digestion. With continuous operation of a laboratory-scale aerobic digester at high dissolved oxygen concentration (DO>4 mg O2 L-1) and low pH (4.7±0.6), a significant amount of total nitrogen (TN) loss (i.e., 18.6±1.5% of TN in feed sludge) was detected. Notably, ∼40% of the removed TN was emitted as NO, with ∼8% as N2O. A series of batch assays were then designed to explain the observed TN loss under aerobic conditions. All assays were conducted with a low concentration of volatile solids (VS), i.e., VS<4.5 g L-1. This VS concentration is commensurate with the values commonly found in the aeration tanks of full-scale wastewater treatment systems, and thus no significant nitrogen loss should be expected when DO is controlled above 4 mg O2 L-1. However, nitrite disappeared at a significant rate (with the chemical decomposition of nitrite excluded), leading to NO production in the batch assays at pH 5. The nitrite reduction could be associated with endogenous microbial activities, e.g., nitrite detoxification. The significant NO production illustrates the importance of aerobic nitrite reduction during acidic aerobic sludge digestion, suggesting this process cannot be neglected in developing acidic activated sludge technology.
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Affiliation(s)
- Xi Lu
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Zhiyao Wang
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Haoran Duan
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Ziping Wu
- School of Chemical Engineering, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Shihu Hu
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Liu Ye
- School of Chemical Engineering, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Zhiguo Yuan
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Min Zheng
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, St Lucia, QLD 4072, Australia.
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6
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Faust V, van Alen TA, Op den Camp HJ, Vlaeminck SE, Ganigué R, Boon N, Udert KM. Ammonia oxidation by novel " Candidatus Nitrosacidococcus urinae" is sensitive to process disturbances at low pH and to iron limitation at neutral pH. WATER RESEARCH X 2022; 17:100157. [PMID: 36262799 PMCID: PMC9574496 DOI: 10.1016/j.wroa.2022.100157] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 09/06/2022] [Accepted: 10/02/2022] [Indexed: 05/06/2023]
Abstract
Acid-tolerant ammonia-oxidizing bacteria (AOB) can open the door to new applications, such as partial nitritation at low pH. However, they can also be problematic because chemical nitrite oxidation occurs at low pH, leading to the release of harmful nitrogen oxide gases. In this publication, the role of acid-tolerant AOB in urine treatment was explored. On the one hand, the technical feasibility of ammonia oxidation under acidic conditions for source-separated urine with total nitrogen concentrations up to 3.5 g-N L-1 was investigated. On the other hand, the abundance and growth of acid-tolerant AOB at more neutral pH was explored. Under acidic conditions (pH of 5), ammonia oxidation rates of 500 mg-N L-1 d-1 and 10 g-N g-VSS-1 d-1 were observed, despite high concentrations of 15 mg-N L-1 of the AOB-inhibiting compound nitrous acid and low concentration of 0.04 mg-N L-1 of the substrate ammonia. However, ammonia oxidation under acidic conditions was very sensitive to process disturbances. Even short periods of less than 12 h without oxygen or without influent resulted in a complete cessation of ammonia oxidation with a recovery time of up to two months, which is a problem for low maintenance applications such as decentralized treatment. Furthermore, undesirable nitrogen losses of about 10% were observed. Under acidic conditions, a novel AOB strain was enriched with a relative abundance of up to 80%, for which the name "Candidatus (Ca.) Nitrosacidococcus urinae" is proposed. While Nitrosacidococcus members were present only to a small extent (0.004%) in urine nitrification reactors operated at pH values between 5.8 and 7, acid-tolerant AOB were always enriched during long periods without influent, resulting in an uncontrolled drop in pH to as low as 2.5. Long-term experiments at different pH values showed that the activity of "Ca. Nitrosacidococcus urinae" decreased strongly at a pH of 7, where they were also outcompeted by the acid-sensitive AOB Nitrosomonas halophila. The experiment results showed that the decreased activity of "Ca. Nitrosacidococcus urinae" correlated with the limited availability of dissolved iron at neutral pH.
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Affiliation(s)
- Valentin Faust
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- ETH Zürich, Institute of Environmental Engineering, 8093 Zürich, Switzerland
| | - Theo A. van Alen
- Department of Microbiology, RIBES, Radboud University Nijmegen, 0268 Nijmegen, The Netherlands
| | - Huub J.M. Op den Camp
- Department of Microbiology, RIBES, Radboud University Nijmegen, 0268 Nijmegen, The Netherlands
| | - Siegfried E. Vlaeminck
- Research Group of Sustainable Energy, Air and Water Technology, Department of Bioscience Engineering, Faculty of Science, University of Antwerp, 2020 Antwerpen, Belgium
- Centre for Advanced Process Technology for Urban Resource Recovery (CAPTURE), 9052 Gent, Belgium
| | - Ramon Ganigué
- Centre for Advanced Process Technology for Urban Resource Recovery (CAPTURE), 9052 Gent, Belgium
- Center for Microbial Ecology and Technology (CMET), Faculty of Bioscience Engineering, Ghent University, 9000 Gent, Belgium
| | - Nico Boon
- Centre for Advanced Process Technology for Urban Resource Recovery (CAPTURE), 9052 Gent, Belgium
- Center for Microbial Ecology and Technology (CMET), Faculty of Bioscience Engineering, Ghent University, 9000 Gent, Belgium
| | - Kai M. Udert
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- ETH Zürich, Institute of Environmental Engineering, 8093 Zürich, Switzerland
- Corresponding author at: Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland.
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7
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Wu Z, Duan H, Li K, Ye L. A comprehensive carbon footprint analysis of different wastewater treatment plant configurations. ENVIRONMENTAL RESEARCH 2022; 214:113818. [PMID: 35843274 DOI: 10.1016/j.envres.2022.113818] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 05/30/2022] [Accepted: 06/30/2022] [Indexed: 06/15/2023]
Abstract
With the growing concern of global warming, many water utilities are pioneering in mitigating greenhouse gas (GHG) emissions, with some water utilities aiming to achieve net-zero emissions operation in the next decade. However, for wastewater treatment plants (WWTPs), the carbon footprint of different treatment technologies and its contribution among various units within each treatment configuration is still unclear. This study evaluates the impacts of process design on the carbon footprint of WWTPs through the analysis of scope 1 (direct emission), scope 2 (indirect emission), and scope 3 (value chain emission) emissions. The comprehensive configuration design in this work considered three nutrient removal processes including typical aerobic and anaerobic wastewater treatment technologies. Emissions from the sludge management processes are also calculated, including aerobic and anaerobic sludge stabilization processes, short-term and long-term sludge storage, and three sludge disposal options. In total, 45 processes were analysed and the results were compared. The results showed the carbon footprints are highly dependent on the treatment configurations of WWTPs. Analysis suggested scope 2 & 3 emissions can be reduced by selecting suitable processes. In general, anaerobic wastewater and sludge stabilization technologies are more suitable than aerobic technologies to reduce scope 2 & 3 emissions, leading to a lower overall carbon footprint. In comparison, configuration design offers limited opportunities to reduce scope 1 emissions, which may be the future challenge for WWTP to achieve carbon neutrality.
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Affiliation(s)
- Ziping Wu
- School of Chemical Engineering, The University of Queensland, St Lucia, QLD, Australia
| | - Haoran Duan
- School of Chemical Engineering, The University of Queensland, St Lucia, QLD, Australia; Australian Centre for Water and Environmental Biotechnology (ACWEB, Formerly AWMC), The University of Queensland, St. Lucia, QLD, 4072, Australia.
| | - Kaili Li
- School of Chemical Engineering, The University of Queensland, St Lucia, QLD, Australia
| | - Liu Ye
- School of Chemical Engineering, The University of Queensland, St Lucia, QLD, Australia.
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8
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Duan H, Watts S, Zheng M, Wang Z, Zhao J, Li H, Liu P, Dwyer J, McPhee P, Rattier M, Larsen E, Yuan Z, Hu S. Achieving robust mainstream nitrite shunt at pilot-scale with integrated sidestream sludge treatment and step-feed. WATER RESEARCH 2022; 223:119034. [PMID: 36067606 DOI: 10.1016/j.watres.2022.119034] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 08/19/2022] [Accepted: 08/27/2022] [Indexed: 06/15/2023]
Abstract
As a promising energy- and carbon efficient process for nitrogen removal from wastewater, mainstream nitrite shunt has been extensively researched. However, beyond the laboratory it is challenging to maintain stable performance by suppressing nitrite-oxidising bacteria (NOB). In this study, a pilot-scale reactor system receiving real sewage was operated in two stages for >850 days to evaluate two novel NOB suppression strategies for achieving nitrite shunt: i) sidestream sludge treatment based on alternating free nitrous acid (FNA) and free ammonia (FA) and ii) sidestream FNA/FA sludge treatment integrated with in-situ NOB suppression via step-feed. The results showed that, with sidestream sludge treatment alone, NOB developed resistance relatively quickly to the treatment, leading to unstable nitrite shunt. In contrast, robust nitrite shunt was achieved and stably maintained for more than a year when sidestream sludge treatment was integrated with a step-feed strategy. Kinetic analyses suggested that sludge treatment and step-feed worked in synergy, leading to stable NOB suppression. The integrated strategy demonstrated in this study removes a key barrier to the implementation of stable mainstream nitrite shunt.
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Affiliation(s)
- Haoran Duan
- Australian Centre for Water and Environmental Biotechnology (formerly AWMC), The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Shane Watts
- Australian Centre for Water and Environmental Biotechnology (formerly AWMC), The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Min Zheng
- Australian Centre for Water and Environmental Biotechnology (formerly AWMC), The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Zhiyao Wang
- Australian Centre for Water and Environmental Biotechnology (formerly AWMC), The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Jing Zhao
- Australian Centre for Water and Environmental Biotechnology (formerly AWMC), The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Huijuan Li
- Australian Centre for Water and Environmental Biotechnology (formerly AWMC), The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Peng Liu
- Australian Centre for Water and Environmental Biotechnology (formerly AWMC), The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Jason Dwyer
- Urban Utilities, Brisbane, QLD, 4000, Australia
| | - Paul McPhee
- Urban Utilities, Brisbane, QLD, 4000, Australia
| | - Maxime Rattier
- Australian Centre for Water and Environmental Biotechnology (formerly AWMC), The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Eloise Larsen
- Australian Centre for Water and Environmental Biotechnology (formerly AWMC), The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Zhiguo Yuan
- Australian Centre for Water and Environmental Biotechnology (formerly AWMC), The University of Queensland, Brisbane, QLD, 4072, Australia.
| | - Shihu Hu
- Australian Centre for Water and Environmental Biotechnology (formerly AWMC), The University of Queensland, Brisbane, QLD, 4072, Australia.
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9
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Wang Z, Zheng M, Duan H, Yuan Z, Hu S. A 20-Year Journey of Partial Nitritation and Anammox (PN/A): from Sidestream toward Mainstream. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:7522-7531. [PMID: 35657148 DOI: 10.1021/acs.est.1c06107] [Citation(s) in RCA: 70] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Anaerobic ammonium oxidation (anammox) was discovered as a new microbial reaction in the late 1990s, which led to the development of an innovative energy- and carbon-efficient technology─partial nitritation and anammox (PN/A)─for nitrogen removal. PN/A was first applied to remove the nitrogen from high-strength wastewaters, e.g., anaerobic digestion liquor (i.e., sidestream), and further expanded to the main line of wastewater treatment plants (i.e., mainstream). While sidestream PN/A has been well-established with extensive full-scale installations worldwide, practical application of PN/A in mainstream treatment has been proven extremely challenging to date. A key challenge is achieving stable suppression of nitrite-oxidizing bacteria (NOB). This study examines the progress of NOB suppression in both sidestream- and mainstream PN/A over the past two decades. The successful NOB suppression in sidestream PN/A was reviewed, and these successes were evaluated in terms of their transferability into mainstream PN/A. Drawing on the learning over the past decades, we anticipate that a hybrid process, comprised of biofilm and floccular sludge, bears great potential to achieve efficient mainstream PN/A, while a combination of strategies is entailed for stable NOB suppression. Furthermore, the recent discovery of novel nitrifiers would trigger new opportunities and new challenges for mainstream PN/A.
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Affiliation(s)
- Zhiyao Wang
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Min Zheng
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Haoran Duan
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Zhiguo Yuan
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Shihu Hu
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, Brisbane, Queensland 4072, Australia
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10
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He D, Zheng S, Xiao J, Ye Y, Liu X, Yin Z, Wang D. Effect of lignin on short-chain fatty acids production from anaerobic fermentation of waste activated sludge. WATER RESEARCH 2022; 212:118082. [PMID: 35123382 DOI: 10.1016/j.watres.2022.118082] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/12/2022] [Accepted: 01/14/2022] [Indexed: 05/21/2023]
Abstract
Lignin, a biological resource with great potential, can be as high as ∼16% of the total organics in the waste activated sludge (WAS). This work therefore aims to fill the knowledge gap about the effect of lignin on short-chain fatty acids (SCFAs) production from anaerobic fermentation of sludge. Experimental results showed that lignin promoted rather than inhibited SCFAs production. Specifically, the presence of 15% lignin promoted the SCFAs production from 129.1 ± 6.5 to 223.14 ± 7.8 mg COD/g VSS compared with the control, and the proportion of acetic increased by 61.8%, while that of propionic decreased by 44.9%. Mechanism exploration revealed that lignin improved the solubilization of biodegradable substrates due to its hydrophobic characteristics. In addition, lignin enhanced the acidogenesis process, possibly by perfecting the electron transfer chain in the fermentation system, and the quinone structure in lignin may compete electrons with methanogens to inhibit the consumption of SCFAs. Microbiological analysis showed that the abundance of microorganisms related to acidogenesi, especially the acetogenesis, including Proteiniclasticum sp., Acetoanaerobium sp., in the fermenter with lignin increased, which caused the community to shift towards specialized and diverse SCFAs production.
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Affiliation(s)
- Dandan He
- Department of Dermatology, Second Xiangya Hospital, Central South University, Changsha 410011, PR China; College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Shilin Zheng
- Department of Dermatology, Second Xiangya Hospital, Central South University, Changsha 410011, PR China; College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Jun Xiao
- Department of Dermatology, Second Xiangya Hospital, Central South University, Changsha 410011, PR China; College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Yuhang Ye
- Department of Dermatology, Second Xiangya Hospital, Central South University, Changsha 410011, PR China; College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Xuran Liu
- Department of Dermatology, Second Xiangya Hospital, Central South University, Changsha 410011, PR China; College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Zhuo Yin
- Department of Dermatology, Second Xiangya Hospital, Central South University, Changsha 410011, PR China.
| | - Dongbo Wang
- Department of Dermatology, Second Xiangya Hospital, Central South University, Changsha 410011, PR China; College of Environmental Science and Engineering, Hunan University and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
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11
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Wang C, Wei W, Mannina G, Dai X, Ni BJ. Unveiling the distinctive role of titanium dioxide nanoparticles in aerobic sludge digestion. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 813:151872. [PMID: 34826477 DOI: 10.1016/j.scitotenv.2021.151872] [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: 10/11/2021] [Revised: 11/17/2021] [Accepted: 11/18/2021] [Indexed: 06/13/2023]
Abstract
Aerobic digestion is considered to be a common process for the stabilization of waste activated sludge (WAS) in the small-sized wastewater treatment systems, while the broad application of titanium dioxide nanoparticles (TiO2 NPs) results in their unavoidable existence in WAS aerobic digestion, with its role in aerobic sludge digestion being never documented. This study set up a series of aerobic sludge digesters to evaluate the previously unknown role of TiO2 NPs on the performance of the digesters. The volatile solids (VS) degradation percentage increased from 21.9 ± 0.6% to 26.9 ± 0.1% - 30.0 ± 0.3% with the different contents of TiO2 NPs (0, 1, 20 and 50 mg/L). Similarly, the total inorganic nitrogen production increased from 23.1 ± 0.3 to 31.0 ± 0.1 mg N/g VS with the rising TiO2 NPs concentrations from 0 to 50 mg/L. The microbial analysis suggested that TiO2 NPs contributed to the accumulation of specific microbes correlated with the degradation of organic substances and the conversion of nitrogen compounds. Model-based analysis showed the higher biodegradability and hydrolysis rate of sludge with TiO2 NPs. Further mechanistic studies indicated that the enhancement of WAS solubilization and the degradation of recalcitrant substances (e.g., humic acid and cellulose) contributed to the better performance of experimental aerobic digesters, which was confirmed by the fourier transformation infrared spectroscopy (FTIR) indicating the converting of these materials into biodegradable substrates for digestion with TiO2 NPs. It could be inferred from this investigation that aerobic digestion rather than anaerobic digestion would be a more suitable treatment method for sludge containing TiO2 NPs.
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Affiliation(s)
- Chen Wang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China
| | - Wei Wei
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Giorgio Mannina
- Engineering Department, Palermo University, Viale delle Scienze, Ed.8, 90128 Palermo, Italy
| | - Xiaohu Dai
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China
| | - Bing-Jie Ni
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia.
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12
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Wang C, Wei W, Dai X, Ni BJ. Calcium peroxide significantly enhances volatile solids destruction in aerobic sludge digestion through improving sludge biodegradability. BIORESOURCE TECHNOLOGY 2022; 346:126655. [PMID: 34979280 DOI: 10.1016/j.biortech.2021.126655] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/23/2021] [Accepted: 12/26/2021] [Indexed: 06/14/2023]
Abstract
This work put up a novel strategy of applying calcium peroxide (CaO2) in aerobic sludge digestion and provided insights into such system. The degradation percentage of sludge and total inorganic nitrogen production in the digesters with CaO2 at 0.02 g/g-VS-WAS increased by 25.8% and 18.8% of control. CaO2 addition allowed various key microbes related to organics degradation to accumulate in the system. Moreover, the modelling and chemical (i.e., excitation emission matrix (EEM) fluorescence and fourier transformation spectroscopy (FTIR)) analyses revealed that CaO2 addition enhanced sludge biodegradability with more release of biodegradable organics and increased degradation of recalcitrant organics, which can be transformed into biodegradable organics with the action of CaO2. Subsequent transformation test indicated that CaO2 enabled to promote hydrolysis and catabolism of biodegradable substrates in sludge. Further investigations on function mechanism suggested that CaO2 carried on positive action for sludge aerobic digestion mainly through the enhancement by ·OH.
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Affiliation(s)
- Chen Wang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China
| | - Wei Wei
- School of Civil and Environmental Engineering, Centre for Technology in Water and Wastewater, University of Technology Sydney, Sydney, NSW 2007, Australia.
| | - Xiaohu Dai
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China
| | - Bing-Jie Ni
- School of Civil and Environmental Engineering, Centre for Technology in Water and Wastewater, University of Technology Sydney, Sydney, NSW 2007, Australia
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13
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Calderon AG, Duan H, Seo KY, Macintosh C, Astals S, Li K, Wan J, Li H, Maulani N, Lim ZK, Yuan Z, Hu S. The origin of waste activated sludge affects the enhancement of anaerobic digestion by free nitrous acid pre-treatment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 795:148831. [PMID: 34246135 DOI: 10.1016/j.scitotenv.2021.148831] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 06/29/2021] [Accepted: 06/29/2021] [Indexed: 06/13/2023]
Abstract
Anaerobic digestion is a common stabilization method for treating primary sludge (PS) and waste activated sludge (WAS). However, its application is often limited by the degradation of WAS. Recent studies have demonstrated FNA to be an effective pre-treatment for enhancing WAS degradability, while having limited effect on PS degradability. WAS characteristics are impacted by wastewater treatment plant (WWTP) configuration and this study is the first to compare the effectiveness of FNA pre-treatment on WAS from WWTP with and without primary treatment. In this study, WAS samples were collected from four full-scale WWTPs with or without primary treatment. Sludge characterization, biomethane potential tests and mathematical modeling were conducted to assess the impacts of FNA pre-treatment on anaerobic digestion. The results showed that FNA pre-treatment was consistently effective for WAS from different WWTPs, while the extent of enhancement varied between WWTPs. For WAS from WWTPs without primary treatment, FNA pretreatment increased the rate of hydrolysis by 54-66% compared to 22-33% increase for WAS without primary treatment. In contrast, WAS from WWTPs with primary treatment experienced greater increases in methane potential (22-24%) compared to WAS from WWTPs without primary treatment (14-16%). These variances could be associated with primary treatment impacting the wastewater COD/N ratio and thus portion of extracellular polymetric substances (EPS) and cells in WAS. FNA pre-treatment targets the destruction of polymetric substances and cells, therefore WAS with a higher proportion of cells (i.e., WAS with primary treatment) experienced greater improvements in methane yield. Similarly, greater improvements in hydrolysis rate were observed for WAS from WWTP without primary sedimentation which contain higher proportions of large EPS molecules. Despite its consistent effectiveness on WAS samples, FNA pre-treatment was ineffective for improving the digestibility of high-rate activated sludge (HRAS).
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Affiliation(s)
| | - Haoran Duan
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia; School of Chemical Engineering, The University of Queensland, St Lucia, QLD 4072, Australia.
| | - Kai Yee Seo
- School of Chemical Engineering, The University of Queensland, St Lucia, QLD 4072, Australia
| | | | - Sergi Astals
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia; Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, C/ Martí i Franquès 1, 08028 Barcelona, Spain
| | - Kaili Li
- School of Chemical Engineering, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Jingjing Wan
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Huijuan Li
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Nova Maulani
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Zhuan Khai Lim
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Zhiguo Yuan
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Shihu Hu
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
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14
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Liu T, Lu Y, Zheng M, Hu S, Yuan Z, Guo J. Efficient nitrogen removal from mainstream wastewater through coupling Partial Nitritation, Anammox and Methane-dependent nitrite/nitrate reduction (PNAM). WATER RESEARCH 2021; 206:117723. [PMID: 34637975 DOI: 10.1016/j.watres.2021.117723] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 08/29/2021] [Accepted: 09/26/2021] [Indexed: 06/13/2023]
Abstract
The application of partial nitritation and anammox to remove nitrogen from mainstream wastewater is of great interest because of the potential to reduce energy cost and carbon dosage. However, this process confronts a dilemma of relatively high effluent nitrogen concentration (>10 mg N/L), owning to the unwanted prevalence of nitrite-oxidizing bacteria (NOB) and the intrinsic nitrate production by anammox bacteria. Here, a novel technology, named the one-stage PNAM, that integrates Partial Nitritation, Anammox and Methane-dependent nitrite/nitrate reduction reactions, was developed in a single membrane biofilm reactor (MBfR). With feeding of synthetic mainstream wastewater containing ∼50 mg NH4+-N/L at a hydraulic retention time of 12 h, more than 95% nitrogen was removed in the established one-stage PNAM process at a practically useful rate of 0.1 kg N/m3/d. Microbial community characterization and in-situ batch tests revealed a sophisticated microbial structure consisting of ammonia-oxidizing bacteria (AOB), anammox bacteria, nitrite/nitrate-dependent anaerobic methane oxidation (n-DAMO) bacteria and archaea, and a small fraction of NOB and aerobic methanotrophs. The role of methane in removing nitrate was confirmed by switching on/off the methane supply, which relaxed the requirement for NOB suppression. In addition, the established system was relatively robust against temperature variations, evidenced by a total nitrogen removal efficiency above 80% at temperature as low as 14 ℃. The results provide a promising alternative for efficient nitrogen removal from domestic wastewater using methane as the sole carbon source.
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Affiliation(s)
- Tao Liu
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Yan Lu
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Min Zheng
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Shihu Hu
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Zhiguo Yuan
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Jianhua Guo
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, St. Lucia, Queensland 4072, Australia.
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15
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Wang Z, Liu T, Duan H, Song Y, Lu X, Hu S, Yuan Z, Batstone D, Zheng M. Post-treatment options for anaerobically digested sludge: Current status and future prospect. WATER RESEARCH 2021; 205:117665. [PMID: 34547700 DOI: 10.1016/j.watres.2021.117665] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/15/2021] [Accepted: 09/10/2021] [Indexed: 05/16/2023]
Abstract
Anaerobic digestion is the most commonly used sludge treatment technology in large-scale wastewater treatment plants (WWTPs), generating two main products, i.e., biogas and anaerobically digested (AD) sludge. Biogas can be used as a source of renewable energy, and AD sludge is often transported for agricultural land application. Land application of AD sludge is confronted with ever-increasing economic and regulatory pressures due to its high water content, high organic content and related odour and pathogen content (if poorly stabilized), as well as potential toxic metal and organic contaminants. To address these challenges, a number of technologies have been developed for the further treatment of AD sludge before final disposal. This review aims to critically evaluate these state-of-the-art technologies. These technologies were categorized based on their primary aims: 1) dewaterability enhancement; 2) solids reduction and stabilization; 3) toxic metals removal. At present, the goal of post-treatment mainly focuses on dewaterability enhancement, to reduce transport costs. In future, we propose that the post-treatment of AD sludge should orient towards multiple aims, i.e., an integrated approach enabling sludge volume reduction, stabilization (including pathogen removal), and metal solubilization simultaneously. Two promising technical routes are suggested as examples, i.e. physio-chemical iron-based advanced oxidation and biological acidic aerobic digestion, while more approaches need to be developed in future studies. We concluded that post-treatment of AD sludge will promote the AD sludge management towards a more economically favourable, socially acceptable, and environmentally sustainable way; however, further development and rigorous evaluation are required for a wider adoption.
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Affiliation(s)
- Zhiyao Wang
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Tao Liu
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Haoran Duan
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Yarong Song
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Xi Lu
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Shihu Hu
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Zhiguo Yuan
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Damien Batstone
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Min Zheng
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia.
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16
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Calderon AG, Duan H, Chen X, Wu Z, Yu W, Silva CE, Li Y, Shrestha S, Wang Z, Keller J, Chen Z, Yuan Z, Hu S. Enhancing anaerobic digestion using free nitrous acid: Identifying the optimal pre-treatment condition in continuous operation. WATER RESEARCH 2021; 205:117694. [PMID: 34607085 DOI: 10.1016/j.watres.2021.117694] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 08/17/2021] [Accepted: 09/20/2021] [Indexed: 05/23/2023]
Abstract
Free Nitrous Acid (FNA) pre-treatment is a promising technology demonstrated effective in improving waste activated sludge degradability and anaerobic digestion (AD) performance. Pre-treatment conditions including FNA concentration and treatment duration determine operational and capital cost of full-scale implementation, which have not been studied in long-term experiments. The knowledge of FNA pre-treatment conditions improving the AD performance is urgently required to determine suitable conditions for the technology implementation. In this work, five different FNA concentrations (2.2, 4.4, 7.2, 12 mgN/L and nitrite only without pH adjustment) and three treatment durations (8, 24 and 48 h) were studied in four lab-scale semi-continuous AD reactors for over 300 days. FNA pre-treatment was shown under all tested conditions effective in enhancing AD performances, while its effectiveness and resulted benefits varied substantially amongst different pre-treatment conditions. The long-term experiment demonstrated that the methane production, sludge reduction and digested sludge viscosity of AD are positively correlated with the FNA concentration and durations, until an optimal condition is reached, which was identified in this work to be FNA concentration of 7.2 mgN/L and treatment duration of 24 h. Microbial community changes supported the apparent observation of enhanced sludge degradation at elevating FNA concentrations applied during pre-treatment. The short-term sludge solubilization results were inconsistent with the long-term AD performance, which was potentially caused by inhibitions from stringent FNA pre-treatment conditions applied (FNA = 12 mgN/L with 24-hour treatment & FNA = 7.2 mgN/L with 48-hour treatment). Overall, results suggested FNA pre-treatment at the optimized condition is highly beneficial to WWTPs and competitive with other pre-treatment technologies, e.g., thermal hydrolysis pre-treatment. This work comprehensively evaluated the key design parameters of FNA pre-treatment process, reached a major milestone in the development and applications of FNA technologies.
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Affiliation(s)
| | - Haoran Duan
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia; School of Chemical Engineering, The University of Queensland, St Lucia, QLD 4072, Australia.
| | - Xiaoguang Chen
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia; State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China
| | - Ziping Wu
- School of Chemical Engineering, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Wenbo Yu
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia; School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Carlos E Silva
- Federal University of Piaui Campus Ministro Petronio Portela Ininga, Teresina, PI 64049550, Brazil
| | - Yijing Li
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Sohan Shrestha
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Zhiyao Wang
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Jurg Keller
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Zhongwei Chen
- School of Mechanical and Mining Engineering, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Zhiguo Yuan
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Shihu Hu
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia.
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17
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Lu X, Duan H, Oehmen A, Carvalho G, Yuan Z, Ye L. Achieving combined biological short-cut nitrogen and phosphorus removal in a one sludge system with side-stream sludge treatment. WATER RESEARCH 2021; 203:117563. [PMID: 34419918 DOI: 10.1016/j.watres.2021.117563] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 08/01/2021] [Accepted: 08/11/2021] [Indexed: 06/13/2023]
Abstract
Biological nitrogen (N) removal via the short-cut pathway (NH4+-N→NO2--N→N2) is economically attractive in wastewater treatment plants (WWTPs). However, biological phosphorus (P) removal processes remain a bottleneck in these systems due to the strong inhibitory effect of nitrite or its protonated form (HNO2, free nitrous acid - FNA) on polyphosphate accumulating organisms (PAOs). In this study, a novel combined nitrogen and phosphorus removal strategy was verified and achieved in a biological short-cut nitrogen removal system via side-stream sludge treatment with FNA, and the mechanisms impacting this process were investigated. The side-stream FNA treatment process applied here led to a significant reduction in the real sludge retention time (SRT) in the mainstream (approximately 2.7 days) based on the biocidal effect of FNA to the majority of the organisms. This work also found that around 40% of the P uptake activity was still maintained at a much higher FNA level of 38 μg N/L with potential PAOs, which highly broadened the current knowledge of PAOs community. An economic analysis revealed advantages of the proposed as compared to conventional biological nitrogen and phosphorus removal (13% savings in total cost), biological short-cut nitrogen removal (via FNA treatment) with chemical phosphorus precipitation (21% savings) and conventional biological nitrogen removal with chemical precipitation (27% savings). Overall, this study presents a novel and viable retrofit strategy in integrating biological short-cut nitrogen removal with EBPR for next generation WWTPs.
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Affiliation(s)
- Xuanyu Lu
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia; School of Chemical Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Haoran Duan
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia; School of Chemical Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Adrian Oehmen
- School of Chemical Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Gilda Carvalho
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Zhiguo Yuan
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Liu Ye
- School of Chemical Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia.
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18
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Wei W, Chen X, Liu Y, Ni BJ. Aerobic sludge digestion is distinguishingly affected by the different entering pathways of zinc oxide nanoparticles. JOURNAL OF HAZARDOUS MATERIALS 2021; 416:125799. [PMID: 33838507 DOI: 10.1016/j.jhazmat.2021.125799] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 03/28/2021] [Accepted: 03/29/2021] [Indexed: 06/12/2023]
Abstract
Zinc oxide nanoparticles (ZnO NPs) are widespread emerging pollutants raising global concerns about their influences on biological wastewater treatment processes. However, the impacts of ZnO NPs on aerobic sludge digestion that is a major sludge treatment process remain unknown. Herein, this study comprehensively investigated the key influences of ZnO NPs on aerobic digestion of waste activated sludge (WAS) and the potential mechanisms involved. Two different entering pathways, i.e., ZnO NPs directly entered into aerobic sludge digester and ZnO NPs initially entered into wastewater bio-treatment reactor, were tested to evaluate the different impacts. Compared to the control, ZnO NPs initially entering into wastewater bioreactor inhibited WAS degradation by 18.2 ± 0.1%, whereas ZnO NPs immediately entered into digester inhibited it by 29.7 ± 0.1%. This was accompanied by a similar decrease in inorganic nitrogen production and oxygen consumption. ZnO NPs exposure in wastewater bioreactor changed WAS characteristics in favor of solubilization in aerobic digestion. Modelling analysis indicated that ZnO NPs inhibited WAS hydrolysis, especially for their direct entering into aerobic digester. Correspondingly, microbial community was shifted in the direction against aerobic digestion by the ZnO NPs. Excessive oxidative stress and Zn2+ release represented the primary toxicity factors for the inhibition.
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Affiliation(s)
- Wei Wei
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Xueming Chen
- Fujian Provincial Engineering Research Center of Rural Waste Recycling Technology, College of Environment and Resources, Fuzhou University, Fuzhou, Fujian 350116, China
| | - Yiwen Liu
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Bing-Jie Ni
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia.
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19
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Wang Z, Ni G, Maulani N, Xia J, De Clippeleir H, Hu S, Yuan Z, Zheng M. Stoichiometric and kinetic characterization of an acid-tolerant ammonia oxidizer 'Candidatus Nitrosoglobus'. WATER RESEARCH 2021; 196:117026. [PMID: 33751975 DOI: 10.1016/j.watres.2021.117026] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 03/07/2021] [Accepted: 03/08/2021] [Indexed: 05/06/2023]
Abstract
Recently, acidic (i.e. pH<5) nitrification in activated-sludge is attracting attention because it enables stable nitritation (NH4+ → NO2-), and enhances sludge reduction and stabilization. However, the key acid-tolerant ammonia oxidizers involved are poorly understood. In this study, we performed stoichiometric and kinetic characterization of a new acid-tolerant ammonia-oxidizing bacterium (AOB) belonging to gamma-proteobacterium, Candidatus Nitrosoglobus. Ca. Nitrosoglobus was cultivated in activated-sludge in a laboratory membrane bioreactor over 200 days, with a relative abundance of 55.1 ± 0.5% (indicated by 16S rRNA gene amplicon sequencing) at the time of the characterization experiments. Among all known nitrifiers, Ca. Nitrosoglobus bears the highest resistance to nitrite, low pH, and free nitrous acid (FNA). These traits define Ca. Nitrosoglobus as an adversity-strategist that tends to prosper in acidic activated-sludge, where the low pH (< 5.0) and high levels of FNA (at parts per million levels) sustained and inhibited all other nitrifiers. In contrast, in the conventional pH-neutral activated-sludge process, Ca. Nitrosoglobus is less competitive with canonical AOB (e.g. Nitrosomonas) due to the relatively slow specific growth rate and low affinities to both oxygen and total ammonia. These results advance our understanding of acid-tolerant ammonia oxidizers, and support further development of the acidic activated-sludge process in which Ca. Nitrosoglobus can play a critical role.
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Affiliation(s)
- Zhiyao Wang
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Gaofeng Ni
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Nova Maulani
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Jun Xia
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Haydée De Clippeleir
- District of Columbia Water and Sewer Authority, 5000 Overlook Ave. SW, Washington, DC 20032, USA
| | - Shihu Hu
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Zhiguo Yuan
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Min Zheng
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia.
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20
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Calderon AG, Duan H, Meng J, Zhao J, Song Y, Yu W, Hu Z, Xu K, Cheng X, Hu S, Yuan Z, Zheng M. An integrated strategy to enhance performance of anaerobic digestion of waste activated sludge. WATER RESEARCH 2021; 195:116977. [PMID: 33684677 DOI: 10.1016/j.watres.2021.116977] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 01/20/2021] [Accepted: 02/23/2021] [Indexed: 05/06/2023]
Abstract
Anaerobic digestion (AD) is an essential process in wastewater treatment plants as it can reduce the amount of waste activated sludge (WAS) for disposal, and also enables the recovery of bioenergy (i.e. methane). Here, a new pretreatment method to enhance anaerobic digestion was achieved by treating thickened WAS (TWAS) with ferric (as FeCl3) and nitrite simultaneously for 24-hour at room temperature. Biochemical methane potential tests showed markedly improved degradability in the pretreated TWAS, with a relative increase in hydrolysis rate by 30%. A comparative experiment with the operation of two continuous-flow anaerobic digesters further demonstrated the improvement in biogas quantity and quality, digestate disposal, and phosphorus recovery in the experimental digester. The dosed FeCl3 (i.e. ~6 mM) decreased the pH of TWAS to ~5, which led to the formation of free nitrous acid (FNA, HNO2) at parts per million levels (i.e. ~6 mg N/L), after dosing nitrite at 250 mg NO2--N/L. This FNA treatment caused a 26% increase in methane yield and volatile solids destruction, 55% reduction in the viscosity of sludge in digester, and 24% less polymer required in further digestate dewatering. In addition, the dosed Fe(III) was reduced to Fe(II) which precipitated sulfide and phosphorus, leading to decreased hydrogen sulfide concentration in biogas, and increased percentage of vivianite in the total crystalline iron species in digested sludge. Our study experimentally demonstrated that combined dosing of FeCl3 and nitrite is a useful pretreatment strategy for improving anaerobic digestion of WAS.
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Affiliation(s)
| | - Haoran Duan
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Jia Meng
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia; State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, 73 Huanghe Road, Harbin 150090, China
| | - Jing Zhao
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Yarong Song
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Wenbo Yu
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia; School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, China
| | - Zhetai Hu
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Kangning Xu
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Collage of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Xiang Cheng
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Collage of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Shihu Hu
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Zhiguo Yuan
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Min Zheng
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia.
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21
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Wang Z, Zheng M, Duan H, Ni G, Yu W, Liu Y, Yuan Z, Hu S. Acidic aerobic digestion of anaerobically-digested sludge enabled by a novel ammonia-oxidizing bacterium. WATER RESEARCH 2021; 194:116962. [PMID: 33657493 DOI: 10.1016/j.watres.2021.116962] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 02/05/2021] [Accepted: 02/21/2021] [Indexed: 06/12/2023]
Abstract
Anaerobic digestion is a commonly used process for the reduction and stabilization of wasted activated sludge generated in wastewater treatment plants. However, anaerobically-digested (AD) sludge is still a problematic waste stream due to its large volume and often poor quality. In this study, two aerobic digesters were set up to treat anaerobically-digested sludge, with one digester operated in self-generated acidic condition as the experimental reactor, and one at neutral pH as the control reactor. The acidic condition in the experimental reactor was driven by an inoculated special ammonia-oxidizing bacterium, 'Candidatus Nitrosoglobus', which can tolerate low pH. As a result of ammonium oxidation by Ca. Nitrosoglobus, the pH decreased to 4.8 ± 0.2 and nitrite accumulated to and stayed at 200.0 ± 17.2 mg N L-1, from which free nitrous acid (FNA) at 8.5 ± 1.8 mg HNO2N L-1 formed in-situ. As a combined effect of low pH and high concentration of FNA, the experimental reactor reduced the total solids (TS), volatile solids (VS) and non-volatile solids (NVS) in the AD sludge by 25.2 ± 7.0%, 29.8 ± 4.3%, and 22.6 ± 5.5%, respectively. In contrast, the control reactor without Ca. Nitrosoglobus inoculation (operated at a near-neutral pH of 6.8 ± 0.3 and no FNA formation) only reduced VS in the AD sludge by 10.4 ± 4.3%, along with negligible NVS reduction. Additionally, the acidic aerobic digestion in the experimental reactor significantly stabilized AD sludge, decreasing the specific oxygen uptake rate (SOUR) to 0.5 ± 0.1 mg O2 g-1VS h-1 and the most probable number (MPN) of Faecal Coliforms to 2.4 ± 0.1 log(MPN g-1TS), both of which meet USEPA standards for Class A biosolids. In comparison, the control reactor produced biosolids at Class B level only, with an SOUR of 1.8 ± 0.2 mg O2 g-1VS h-1 and a Faecal Coliforms MPN of 3.6 ± 0.1 log(MPN g-1TS). By reducing the volume and improving the quality of the AD sludge, the acidic aerobic digestion of AD sludge enabled by Ca. Nitrosoglobus has the potential to significantly save the sludge disposal costs in wastewater treatment.
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Affiliation(s)
- Zhiyao Wang
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Min Zheng
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia.
| | - Haoran Duan
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Gaofeng Ni
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Wenbo Yu
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia; School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Yanchen Liu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Zhiguo Yuan
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Shihu Hu
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia.
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22
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Wei W, Chen X, Peng L, Liu Y, Bao T, Ni BJ. The entering of polyethylene terephthalate microplastics into biological wastewater treatment system affects aerobic sludge digestion differently from their direct entering into sludge treatment system. WATER RESEARCH 2021; 190:116731. [PMID: 33310440 DOI: 10.1016/j.watres.2020.116731] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 11/13/2020] [Accepted: 12/06/2020] [Indexed: 06/12/2023]
Abstract
The entering of the widespread polyethylene terephthalate (PET) microplastics into biological wastewater treatment system results in their retention in sewage sludge, which inevitably enters the sludge treatment system. However, all previous studies regarding the impact of microplastics on sludge treatment system were conducted by directly adding microplastics to system and focusing on anaerobic sludge digestion, although PET microplastics commonly enter into the biological wastewater treatment system first before sludge being subsequently treated. The potential impact of the microplastics on waste activated sludge (WAS) aerobic digestion is also completely missing. Therefore, herein the influences of PET microplastics with different entry paths on WAS aerobic digestion as well as the key mechanisms involved was firstly explored. Experimental results demonstrated that compared to the control test, the entering of PET microplastics to biological wastewater treatment system inhibited WAS aerobic digestion by 10.9 ± 0.1% through the decreased hydrolysis, although WAS solubilization during aerobic digestion was improved due to the change of generated WAS characteristics. In contrast, when PET microplastics was directly added to the sludge aerobic digester, there was little impact on solubilization, while the hydrolysis were inhibited seriously, thereby suppressing WAS aerobic digestion more severely by 28.9 ± 0.1%. Further investigation revealed that PET microplastics reduced the populations of key bacteria (e.g., Saprospiraceae, Chitinophagaceae and Xanthomonadaceae) involved in aerobic digestion via induced oxidative stress or/and releasing toxic chemical. This study provided a more accurate approach to assessing the real situation regarding the influences of PET microplastics on aerobic sludge digestion.
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Affiliation(s)
- Wei Wei
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Xueming Chen
- College of Environment and Resources, Fuzhou University, Fujian 350116, China
| | - Lai Peng
- Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China
| | - Yiwen Liu
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Teng Bao
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Bing-Jie Ni
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia.
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23
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Meng J, Duan H, Li H, Watts S, Liu P, Shrestha S, Zheng M, Yu W, Chen Z, Song Y, Dwyer J, Hu S, Yuan Z. Free nitrous acid pre-treatment enhances anaerobic digestion of waste activated sludge and rheological properties of digested sludge: A pilot-scale study. WATER RESEARCH 2020; 172:115515. [PMID: 31986403 DOI: 10.1016/j.watres.2020.115515] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 12/28/2019] [Accepted: 01/15/2020] [Indexed: 06/10/2023]
Abstract
In this study, the effects of free nitrous acid (FNA) pre-treatment on the rheological properties of digested sludge were investigated at a pilot-scale, along with the improvement in volatile solids (VS) destruction and biogas production. Two pilot-scale anaerobic sludge digesters were operated for one year, one receiving thickened waste activated sludge (TWAS) without pre-treatment (control) and one receiving TWAS pre-treated for 24 h at an FNA concentration of 4.9-6.1 mgN/L (nitrite = 250 mgN/L, pH = 5.0, T = 22-30 °C). The results confirmed the enhancing effect of FNA pre-treatment on methane production (37 ± 1%), consistent with previous laboratory studies. Equally importantly, FNA pre-treatment substantially reduced the shear viscosity of TWAS by 51 ± 8% at 100 s-1 and 49 ± 7% at 250 s-1, likely due to the solubilization of the TWAS (11.1 ± 0.8%). Similarly, FNA pre-treatment also reduced these viscosity parameters of the digested sludge by 80 ± 4% and 78 ± 4%, respectively, caused by both enhanced VS destruction and disintegration of the digested sludge. The dewaterability of digested sludge, assessed by dewatered solids content, capillary suction time and specific resistance to filtration, was not improved by FNA pre-treatment. The polymer requirement for dewatering was reduced by 24 ± 0.6% due to the lower solids concentration in the digested sludge achieved with FNA pre-treatment. The changes to sludge rheological properties revealed in this study further enhances the business case for the FNA pre-treatment technology.
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Affiliation(s)
- Jia Meng
- Advanced Water Management Centre, The University of Queensland, St. Lucia, QLD, 4072, Australia; State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, 73 Huanghe Road, Harbin, 50090, China
| | - Haoran Duan
- Advanced Water Management Centre, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Huijuan Li
- Advanced Water Management Centre, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Shane Watts
- Advanced Water Management Centre, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Peng Liu
- Advanced Water Management Centre, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Sohan Shrestha
- Advanced Water Management Centre, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Min Zheng
- Advanced Water Management Centre, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Wenbo Yu
- Advanced Water Management Centre, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Zhongwei Chen
- School of Mechanical and Mining Engineering, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Yarong Song
- Advanced Water Management Centre, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Jason Dwyer
- Queensland Urban Utilities, Brisbane, QLD, 4000, Australia
| | - Shihu Hu
- Advanced Water Management Centre, The University of Queensland, St. Lucia, QLD, 4072, Australia.
| | - Zhiguo Yuan
- Advanced Water Management Centre, The University of Queensland, St. Lucia, QLD, 4072, Australia.
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24
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Duan H, Gao S, Li X, Ab Hamid NH, Jiang G, Zheng M, Bai X, Bond PL, Lu X, Chislett MM, Hu S, Ye L, Yuan Z. Improving wastewater management using free nitrous acid (FNA). WATER RESEARCH 2020; 171:115382. [PMID: 31855696 DOI: 10.1016/j.watres.2019.115382] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 12/06/2019] [Accepted: 12/07/2019] [Indexed: 05/06/2023]
Abstract
Free nitrous acid (FNA), the protonated form of nitrite, has historically been an unwanted substance in wastewater systems due to its inhibition on a wide range of microorganisms. However, in recent years, advanced understanding of FNA inhibitory and biocidal effects on microorganisms has led to the development of a series of FNA-based applications that improve wastewater management practices. FNA has been used in sewer systems to control sewer corrosion and odor; in wastewater treatment to achieve carbon and energy efficient nitrogen removal; in sludge management to improve the sludge reduction and energy recovery; in membrane systems to address membrane fouling; and in wastewater algae systems to facilitate algae harvesting. This paper aims to comprehensively and critically review the current status of FNA-based applications in improving wastewater management. The underlying mechanisms of FNA inhibitory and biocidal effects are also reviewed and discussed. Knowledge gaps and current limitations of the FNA-based applications are identified; and perspectives on the development of FNA-based applications are discussed. We conclude that the FNA-based technologies have great potential for enhancing the performance of wastewater systems; however, further development and demonstration at larger scales are still required for their wider applications.
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Affiliation(s)
- Haoran Duan
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD, 4072, Australia; School of Chemical Engineering, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Shuhong Gao
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, 73019, United States
| | - Xuan Li
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Nur Hafizah Ab Hamid
- School of Chemical Engineering, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Guangming Jiang
- School of Civil, Mining and Environmental Engineering, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Min Zheng
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Xue Bai
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Philip L Bond
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Xuanyu Lu
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD, 4072, Australia; School of Chemical Engineering, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Mariella M Chislett
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Shihu Hu
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Liu Ye
- School of Chemical Engineering, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Zhiguo Yuan
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD, 4072, Australia.
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25
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Ozone-assisted catalytic oxidation of aqueous nitrite ions on HZSM-5 zeolites. Sci Rep 2019; 9:14322. [PMID: 31586086 PMCID: PMC6778124 DOI: 10.1038/s41598-019-50662-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 09/17/2019] [Indexed: 12/05/2022] Open
Abstract
Simultaneous removal of NOx and SO2 during the wet absorption process has made it possible for nitrogen resource utilization. However, nitrites formation at high ratio in absorption solution would limit its application. In this study, the catalytic oxidation behaviors of aqueous nitrite ions assisted by ozone on HZSM-5 zeolites with different SiO2/Al2O3 ratios have been investigated. The experimental results revealed that the oxidation and disproportionation reactions of nitrite ions took place competitively, both of which were accelerated under acidic condition. Moreover, the introduction of HZSM-5 zeolites and ozone would significantly improve the nitrite oxidation rate, where the zeolites with high SiO2/Al2O3 ratios were found to be more effective owing to the enhanced adsorption of nitrite ions and ozone. Based on the results under different operating conditions (such as O3 concentration, HZSM-5 dosage, pH values and presence of radical scavengers etc.), the reaction mechanism was then proposed. The disproportionation reaction of nitrite ions mainly occurred in the bulk solution. And the catalytic oxidation of nitrite ions over zeolites proceeded via a non-radical surface reaction between the adsorbed nitrite ions and ozone/oxygen molecular.
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