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Yan W, Kaiwen H, Yuchen Z, Bingzheng W, Shuo W, Ji L. Response characteristics of the microbial community, metabolic pathways, and anti-resistance genes under high nitrate and sulfamethoxazole stress in a fluidized sulfur autotrophic denitrification process. BIORESOURCE TECHNOLOGY 2025; 425:132310. [PMID: 40023337 DOI: 10.1016/j.biortech.2025.132310] [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: 12/31/2024] [Revised: 01/31/2025] [Accepted: 02/26/2025] [Indexed: 03/04/2025]
Abstract
The adaptability and microbial response mechanism of a sulfur autotrophic denitrification (SADN) biofilm under high nitrate (NO3--N) and sulfamethoxazole (SMX) stress through long-term operation of a fluidized bioreactor was evaluated. The SADN biofilm adapted to nitrate contents of up to 150 mg/L, and at 1 mg/L SMX, the nitrogen removal efficiency and SMX removal efficiency were as high as 85 % and 64 %, respectively. Microbial adaptation was driven by upregulated secretion of acyl-homoserine lactone (AHL) signal molecules, specifically 3OC6-HSL and 3OC8-HSL, which stabilized at concentrations of 575.7 ng/L and 579.9 ng/L, respectively. These molecules dynamically regulated the composition of extracellular polymeric substances, with total EPS content increasing from 113.37 mg/gVSS in the initial phase to 456.85 mg/gVSS under early SMX exposure, ensuring biofilm structural integrity. Under prolonged SMX stress, Simplicispira emerged as a key genus with a relative abundance of 21.20 %, utilizing apoptotic autotrophic denitrifiers and EPS metabolites as carbon sources for heterotrophic denitrification. This genus harbored critical nitrate reductase genes, including NarG, which accounted for 28.5 % of total functional gene abundance. In addition, SMX stress reduced the abundance of total anti-resistance genes (ARGs), with resistance mechanisms dominated by antibiotic efflux pumps, with the contribution increased from 63 % to 67 %. The relevance of this pump continuously increased, which hindered binding of SMX to cells and effectively reduced its toxicity. The results of this study provide scientific evidence for the application of SADN technology in a high-nitrate and antibiotically stressed environment. The results can further guide practical operations and provide technical support for increasing denitrification efficiency and antibiotic removal capacity in the SADN process.
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Affiliation(s)
- Wang Yan
- Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Ecology, Jiangnan University, Wuxi 214122, China
| | - Huang Kaiwen
- Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Ecology, Jiangnan University, Wuxi 214122, China
| | - Zhou Yuchen
- Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Ecology, Jiangnan University, Wuxi 214122, China
| | - Wang Bingzheng
- Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Ecology, Jiangnan University, Wuxi 214122, China
| | - Wang Shuo
- Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Ecology, Jiangnan University, Wuxi 214122, China; Jiangsu College of Water Treatment Technology and Material Collaborative Innovation Center, Suzhou 215009, China.
| | - Li Ji
- Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Ecology, Jiangnan University, Wuxi 214122, China; Jiangsu College of Water Treatment Technology and Material Collaborative Innovation Center, Suzhou 215009, China.
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Pyo M, Kim D, Kim HS, Hwang MH, Lee S, Lee EJ. Sulfur powder utilization and denitrification efficiency in an elemental sulfur-based membrane bioreactor with coagulant addition. WATER RESEARCH 2025; 272:122882. [PMID: 39674135 DOI: 10.1016/j.watres.2024.122882] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2024] [Revised: 11/15/2024] [Accepted: 11/27/2024] [Indexed: 12/16/2024]
Abstract
The integration of elemental sulfur-based autotrophic denitrification with membrane bioreactor (MBR) technology offers a cost-effective solution for nitrate removal; however, stable operation demands efficient sulfur utilization and phosphorus management. This study explores sulfur consumption dynamics and the impacts of coagulant injection on denitrification efficiency. Sulfur consumption was closely correlated with nitrate removal rates, highlighting the critical role of stoichiometric sulfur availability for sustained denitrification. While coagulant addition enhanced phosphorus removal, excessive dosing impaired elemental sulfur-based microbial activity, reducing nitrate removal efficiency and increasing nitrite accumulation. Notably, microbial community analysis revealed a decline in the abundance of key sulfur-oxidizing bacteria, such as Sulfurimonas, under high coagulant concentrations. These findings emphasize the need for optimized sulfur and coagulant dosing strategies to balance phosphorus and nitrate removal while preserving microbial diversity and reactor stability. This study provides practical insights into operational parameters for efficient and sustainable ESAD-MBR processes.
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Affiliation(s)
- Minsu Pyo
- Department of Environmental Engineering, Daegu University, 201 Daegudae-ro, Jillyang, Gyeongsan-si, Gyeongbuk 38453, Republic of Korea; Graduate School of Water Resources, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 440746, Republic of Korea
| | - Dongyeon Kim
- Department of Environmental Engineering, Daegu University, 201 Daegudae-ro, Jillyang, Gyeongsan-si, Gyeongbuk 38453, Republic of Korea
| | - Hyung Soo Kim
- Graduate School of Water Resources, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 440746, Republic of Korea
| | - Moon-Hyun Hwang
- Institute of Conversions Science, Korea University, 145, Anam-ro, Sungbuk-gu, Seoul 02841, Republic of Korea
| | - Sangyoup Lee
- Institute of Conversions Science, Korea University, 145, Anam-ro, Sungbuk-gu, Seoul 02841, Republic of Korea.
| | - Eui-Jong Lee
- Department of Environmental Engineering, Daegu University, 201 Daegudae-ro, Jillyang, Gyeongsan-si, Gyeongbuk 38453, Republic of Korea.
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Zhai T, Zhang L, Zhang F, Su X, Chen P, Xing Z, Liu H, Zhao T. Characteristics of biofilm layer in a bio-doubling reactor and their impact on aerobic denitrifying bacteria enrichment. ENVIRONMENTAL RESEARCH 2025; 267:120730. [PMID: 39736437 DOI: 10.1016/j.envres.2024.120730] [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: 11/09/2024] [Revised: 12/26/2024] [Accepted: 12/28/2024] [Indexed: 01/01/2025]
Abstract
Microbial loss significantly affects wastewater treatment efficiency. This study simulated the inoculation area of a self-developed biological doubling reactor (BDR) to evaluate the retention efficiency of seven different fillers for aerobic denitrifying bacteria. Over 90 days of continuous operation, the porous filler R3 demonstrated excellent performance, with OD600 values consistently exceeding 1.0 and minimal fluctuation. On day 90, the seed liquid amplified with R3 achieved removal efficiencies of 100% for ammonia nitrogen, 97.75% for total nitrogen, and 96.4% for chemical oxygen demand, outperforming other fillers. Scanning electron microscopy and microscopic analysis revealed that R3's large large specific surface area and volume formed a unique meshed biofilm structure, enhancing oxygen and nutrient transport while minimizing detachment. This promoted effective enrichment and retention of aerobic denitrifying bacteria. Microbial diversity analysis confirmed that Acinetobacter, a key genus involved in aerobic denitrification, dominated the network biofilm on R3, accounting for an average of 35.63%. while granular fillers, due to oxygen limitation, promoted the growth of anaerobic ammonium-oxidizing Alcaligenes. The use of BDR-enhanced MBBR for treating synthetic wastewater resulted in a 29.6% increase in TN removal efficiency, with stable system operation. The use of porous fillers with a high specific volume supports stable biofilm formation and consistent seed liquid output, providing a viable solution to microbial loss in wastewater treatment processes.
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Affiliation(s)
- Tianrui Zhai
- School of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing, 400054, China
| | - Lijie Zhang
- School of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing, 400054, China
| | - Fupan Zhang
- School of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing, 400054, China
| | - Xia Su
- School of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing, 400054, China
| | - Peipei Chen
- School of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing, 400054, China
| | - Zhilin Xing
- School of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing, 400054, China
| | - Hao Liu
- Chongqing shiji eco-environmental science and technology co., ltd, China
| | - Tiantao Zhao
- School of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing, 400054, China.
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Ma WJ, Zhang HM, Tian Y. Rapid start-up sulfur-driven autotrophic denitrification granular process: Extracellular electron transfer pathways and microbial community evolution. BIORESOURCE TECHNOLOGY 2024; 395:130331. [PMID: 38224786 DOI: 10.1016/j.biortech.2024.130331] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Accepted: 01/12/2024] [Indexed: 01/17/2024]
Abstract
Sulfur-driven autotrophic denitrification (SAD) granular process has significant advantages in treating low-carbon/nitrogen wastewater; however, the slow growth rate of sulfur-oxidizing bacteria (SOB) results in a prolonged start-up duration. In this study, the thiosulfate-driven autotrophic denitrification (TAD) was successfully initiated by inoculating anaerobic granular sludge on Day 7. Additionally, the electron donor was successfully transferred to the cheaper elemental sulfur from Day 32 to Day 54 at the nitrogen loading rate of 176.2 g N m-3 d-1. During long term experiment, the granules maintained compact structures with the α-helix/(β-sheet + random coil) of 29.5-40.1 %. Extracellular electron transfer (EET) pathway shifted from indirect to direct when electron donors were switched thiosulfate to elemental sulfur. Microbial analysis suggested that thiosulfate improved EET involving enzymes activity. Thiobacillus and Sulfurimonas were dominant in TAD, whereas Longilinea was enriched in elemental sulfur-driven autotrophic denitrification. Overall, this strategy achieved in-situ enrichment of SOB in granules, thereby shortening start-up process.
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Affiliation(s)
- Wen-Jie Ma
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, MOE), School of Environmental Science and Technology, Dalian University of Technology, No. 2 Linggong Road, Dalian 116024, PR China
| | - Han-Min Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, MOE), School of Environmental Science and Technology, Dalian University of Technology, No. 2 Linggong Road, Dalian 116024, PR China.
| | - Yu Tian
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Environment, Harbin Institute of Technology, Harbin 150090, PR China
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