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Luo X, Guo M, Zheng X, Zheng S, Li S. Distinguished denitrifying phosphorus removal in the high-rate anoxic/microaerobic system for sewage treatment. CHEMOSPHERE 2024; 359:142377. [PMID: 38768781 DOI: 10.1016/j.chemosphere.2024.142377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 04/25/2024] [Accepted: 05/16/2024] [Indexed: 05/22/2024]
Abstract
This study re-evaluated the role of anoxic and anaerobic zones during the enhanced biological phosphorus (P) removal process by investigating the potential effect of introducing an anoxic zone into a high-rate microaerobic activated sludge (MAS) system (1.60-1.70 kg chemical oxygen demand (COD) m-3 d-1), i.e., a high-rate anoxic/microaerobic (A/M) system for sewage treatment. In the absence of a pre-anaerobic zone, introducing an anoxic zone considerably reduced effluent NOx--N concentrations (7.2 vs. 1.5 mg L-1) and remarkably enhanced total nitrogen (75% vs. 89%) and total P (18% vs. 60%) removal and sludge P content (1.48% vs. 1.77% (dry weight)) due to further anoxic denitrifying P removal in the anoxic zone (besides simultaneous nitrification and denitrification in the microaerobic zone). High-throughput pyrosequencing demonstrated the niche differentiation of different polyphosphate accumulating organism (PAO) clades (including denitrifying PAO [DPAO] and non-DPAO) in both systems. Introducing an anoxic zone considerably reduced the total PAO abundance in sludge samples by 42% and modified the PAO community structure, including 17-19 detected genera. The change was solely confined to non-DPAOs, as no obvious change in total abundance or community structure of DPAOs including 7 detected genera was observed. Additionally, introducing an anoxic zone increased the abundance of ammonia-oxidizing bacteria by 39%. The high-rate A/M process provided less aeration, higher treatment capacity, a lower COD requirement, and a 75% decrease in the production of waste sludge than the conventional biological nutrient removal process.
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Affiliation(s)
- Xiaojie Luo
- School of Environment, MOE Key Laboratory of Water and Sediment Sciences/State Key Lab of Water Environment Simulation, Beijing Normal University, Beijing, 100875, China
| | - Mengya Guo
- School of Environment, MOE Key Laboratory of Water and Sediment Sciences/State Key Lab of Water Environment Simulation, Beijing Normal University, Beijing, 100875, China
| | - Xiangnan Zheng
- School of Environment, MOE Key Laboratory of Water and Sediment Sciences/State Key Lab of Water Environment Simulation, Beijing Normal University, Beijing, 100875, China
| | - Shaokui Zheng
- School of Environment, MOE Key Laboratory of Water and Sediment Sciences/State Key Lab of Water Environment Simulation, Beijing Normal University, Beijing, 100875, China.
| | - Shida Li
- School of Environment, MOE Key Laboratory of Water and Sediment Sciences/State Key Lab of Water Environment Simulation, Beijing Normal University, Beijing, 100875, China
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Zheng S, Zheng X, Guo M, Li S. Metabolic inhibitor-free assessment of the heterotrophic ammonia-oxidizing activity in activated sludge. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 901:165907. [PMID: 37527723 DOI: 10.1016/j.scitotenv.2023.165907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 07/20/2023] [Accepted: 07/28/2023] [Indexed: 08/03/2023]
Abstract
When the contributions of three ammonia-oxidizing pathways (heterotrophic or autotrophic aerobic ammonia oxidization, and anammox) to wastewater biological nitrogen removal systems was compared by determining their ammonia-oxidizing activities, the key question is how to accurately determine the potential heterotrophic aerobic ammonia-oxidizing (PHAe) activity when the potential autotrophic aerobic ammonia-oxidizing (PAAe) activity (by ammonia-oxidizing bacteria (AOB) or archaea, or complete ammonia oxidization bacteria) also contributes to ammonia oxidization in PHAe activity assay medium. Using a AOB species and three heterotrophic AOB species as inocula, we demonstrated the feasibility of PHAe activity evaluation in the absence of a metabolic inhibitor, i.e., by subtracting the PAAe activity determined in PAAe activity assay medium from a combination of PAAe and PHAe activity determined in PHAe activity assay medium. Binary organic carbon sources (i.e., glucose and acetate) were included in the PHAe activity assay medium to fulfill the carbon requirements of most heterotrophic AOB genera. Higher ammonia-oxidizing activity in AOB biomass than heterotrophic AOB biomass (35.6 vs. 2.6-10.0 mg NH4+-N g-1 MLSS h-1) provides the remarkable advantages of autotrophic aerobic ammonia oxidization in biological nitrogen removal systems. Ammonia removal in three full-scale biological nitrogen removal systems for sewage treatment was predominantly mediated by PAAe activity (1.9-3.3 vs. 0.0-0.3 mg NH4+-N g1 MLSS h-1).
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Affiliation(s)
- Shaokui Zheng
- School of Environment, MOE Key Laboratory of Water and Sediment Sciences/State Key Lab of Water Environment Simulation, Beijing Normal University, Beijing 100875, China.
| | - Xiangnan Zheng
- School of Environment, MOE Key Laboratory of Water and Sediment Sciences/State Key Lab of Water Environment Simulation, Beijing Normal University, Beijing 100875, China
| | - Mengya Guo
- School of Environment, MOE Key Laboratory of Water and Sediment Sciences/State Key Lab of Water Environment Simulation, Beijing Normal University, Beijing 100875, China
| | - Shida Li
- School of Environment, MOE Key Laboratory of Water and Sediment Sciences/State Key Lab of Water Environment Simulation, Beijing Normal University, Beijing 100875, China
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Luo X, Guo M, Zheng X, Zheng S, Li S. Distinguished denitrifying phosphorus removal in the high-rate anoxic/microaerobic system for sewage treatment. CHEMOSPHERE 2023:139712. [PMID: 37536543 DOI: 10.1016/j.chemosphere.2023.139712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 08/01/2023] [Indexed: 08/05/2023]
Abstract
This study re-evaluated the role of anoxic and anaerobic zones during the enhanced biological phosphorus (P) removal process by investigating the potential effect of introducing an anoxic zone into a high-rate microaerobic activated sludge (MAS) system (1.60-1.70 kg chemical oxygen demand (COD) m-3 d-1), i.e., a high-rate anoxic/microaerobic (A/M) system for sewage treatment. In the absence of a pre-anaerobic zone, introducing an anoxic zone considerably reduced effluent NOx--N concentrations (7.2 vs. 1.5 mg L-1) and remarkably enhanced total nitrogen (75% vs. 89%) and total P (18% vs. 60%) removal and sludge P content (1.48% vs. 1.77% (dry weight)) due to further anoxic denitrifying P removal denitrification in the anoxic zone (besides simultaneous nitrification and denitrification in the microaerobic zone). High-throughput pyrosequencing demonstrated the niche differentiation of different polyphosphate accumulating organism (PAO) clades (including denitrifying PAO [DPAO] and non-DPAO) in both systems. Introducing an anoxic zone considerably reduced the total PAO abundance in sludge samples by 42% and modified the PAO community structure, including 17-19 detected genera. The change was solely confined to non-DPAOs, as no significant change in total abundance or community structure of DPAOs including seven detected genera was observed. Additionally, introducing an anoxic zone increased the abundance of ammonia-oxidizing bacteria by 39%. The high-rate A/M process provided less aeration, higher treatment capacity, a lower COD requirement, and a 75% decrease in the production of waste sludge than the conventional biological nutrient removal process.
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Affiliation(s)
- Xiaojie Luo
- School of Environment, MOE Key Laboratory of Water and Sediment Sciences/State Key Lab of Water Environment Simulation, Beijing Normal University, Beijing, 100875, China
| | - Mengya Guo
- School of Environment, MOE Key Laboratory of Water and Sediment Sciences/State Key Lab of Water Environment Simulation, Beijing Normal University, Beijing, 100875, China
| | - Xiangnan Zheng
- School of Environment, MOE Key Laboratory of Water and Sediment Sciences/State Key Lab of Water Environment Simulation, Beijing Normal University, Beijing, 100875, China
| | - Shaokui Zheng
- School of Environment, MOE Key Laboratory of Water and Sediment Sciences/State Key Lab of Water Environment Simulation, Beijing Normal University, Beijing, 100875, China.
| | - Shida Li
- School of Environment, MOE Key Laboratory of Water and Sediment Sciences/State Key Lab of Water Environment Simulation, Beijing Normal University, Beijing, 100875, China
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The Measurement, Application and Effect of Oxygen in Microbial Fermentations: Focusing on Methane and Carboxylate Production. FERMENTATION-BASEL 2022. [DOI: 10.3390/fermentation8040138] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Oxygen is considered detrimental to anaerobic fermentation processes by many practitioners. However, deliberate oxygen sparging has been used successfully for decades to remove H2S in anaerobic digestion (AD) systems. Moreover, microaeration techniques during AD have shown that small doses of oxygen may enhance process performance and promote the in situ degradation of recalcitrant compounds. However, existing oxygen dosing techniques are imprecise, which has led to inconsistent results between studies. At the same time, real-time oxygen fluxes cannot be reliably quantified due to the complexity of most bioreactor systems. Thus, there is a pressing need for robust monitoring and process control in applications where oxygen serves as an operating parameter or an experimental variable. This review summarizes and evaluates the available methodologies for oxygen measurement and dosing as they pertain to anaerobic microbiomes. The historical use of (micro-)aeration in anaerobic digestion and its potential role in other anaerobic fermentation processes are critiqued in detail. This critique also provides insights into the effects of oxygen on these microbiomes. Our assessment suggests that oxygen dosing, when implemented in a controlled and quantifiable manner, could serve as an effective tool for bioprocess engineers to further manipulate anaerobic microbiomes for either bioenergy or biochemical production.
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Zhang X, Li S, Zheng S, Duan S. Impact of dissolved oxygen and loading rate on NH 3 oxidation and N 2 production mechanisms in activated sludge treatment of sewage. Microb Biotechnol 2020; 14:419-429. [PMID: 32488999 PMCID: PMC7936313 DOI: 10.1111/1751-7915.13599] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Revised: 04/29/2020] [Accepted: 05/04/2020] [Indexed: 01/19/2023] Open
Abstract
Microaerobic activated sludge (MAS) is a one-stage process operated at 0.5-1.0 mg l-1 dissolved oxygen (DO) aiming at simultaneous nitrification and denitrification. We used molecular techniques and a comprehensive nitrogen (N)-transformation activity test to investigate the dominant NH3 -oxidizing and N2 -producing mechanism as well as the dominant ammonia-oxidizing bacteria (AOB) species in sludge samples individually collected from an MAS system and a conventional anoxic/oxic (A/O) system; both systems were operated at a normal loading rate (i.e. 1.0 kg chemical oxygen demand (COD) m-3 day-1 and 0.1 kg NH4 + -N m-3 day-1 ) in our previous studies. The DO levels in both systems (aerobic: conventional A/O system; microaerobic: MAS system) did not affect the dominant NH3 -oxidizing mechanism or the dominant AOB species. This study further demonstrated the feasibility of a higher loading rate (i.e. 2.30 kg COD m-3 day-1 and 0.34 kg NH4 + -N m-3 day-1 ) with the MAS process during sewage treatment, which achieved a 40% reduction in aeration energy consumption than that obtained in the conventional A/O system. The increase in loading rates in the MAS system did not affect the dominant NH3 -oxidizing mechanism but did impact the dominant AOB species. Besides, N2 was predominantly produced by microaerobic denitrification in the MAS system at the two loading rates.
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Affiliation(s)
- Xueyu Zhang
- MOE Key Laboratory of Water and Sediment Sciences/State Key Lab of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China
| | - Shida Li
- MOE Key Laboratory of Water and Sediment Sciences/State Key Lab of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China
| | - Shaokui Zheng
- MOE Key Laboratory of Water and Sediment Sciences/State Key Lab of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China
| | - Shoupeng Duan
- MOE Key Laboratory of Water and Sediment Sciences/State Key Lab of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China
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