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Cheng S, Li H, He X, Chen H, Li L. Improving anammox activity and reactor start-up speed by using CO 2/NaHCO 3 buffer. J Environ Sci (China) 2024; 139:60-71. [PMID: 38105078 DOI: 10.1016/j.jes.2023.05.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 04/28/2023] [Accepted: 05/12/2023] [Indexed: 12/19/2023]
Abstract
Anammox bacteria grow slowly and can be affected by large pH fluctuations. Using suitable buffers could make the start-up of anammox reactors easy and rapid. In this study, the effects of three kinds of buffers on the nitrogen removal and growth characteristics of anammox sludge were investigated. Reactors with CO2/NaHCO3 buffer solution (CCBS) performed the best in nitrogen removal, while 4-(2-hydroxyerhyl)piperazine-1-ethanesulfonic acid (HEPES) and phosphate buffer solution (PBS) inhibited the anammox activity. Reactors with 50 mmol/L CCBS could start up in 20 days, showing the specific anammox activity and anammox activity of 1.01±0.10 gN/(gVSS·day) and 0.83±0.06 kgN/(m3·day), respectively. Candidatus Kuenenia was the dominant anammox bacteria, with a relative abundance of 71.8%. Notably, anammox reactors could also start quickly by using 50 mmol/L CCBS under non-strict anaerobic conditions. These findings are meaningful for the quick start-up of engineered anammox reactors and prompt enrichment of anammox bacteria.
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Affiliation(s)
- Shaoan Cheng
- State Key Laboratory of Clean Energy Utilization, College of Energy Engineering, Zhejiang University, Hangzhou 310027, China.
| | - Huahua Li
- State Key Laboratory of Clean Energy Utilization, College of Energy Engineering, Zhejiang University, Hangzhou 310027, China
| | - Xinyuan He
- State Key Laboratory of Clean Energy Utilization, College of Energy Engineering, Zhejiang University, Hangzhou 310027, China
| | - Hua Chen
- State Key Laboratory of Clean Energy Utilization, College of Energy Engineering, Zhejiang University, Hangzhou 310027, China
| | - Longxin Li
- State Key Laboratory of Clean Energy Utilization, College of Energy Engineering, Zhejiang University, Hangzhou 310027, China
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Yi X, Wang Z, Zhao P, Song W, Wang X. New insights on destruction mechanisms of waste activated sludge during simultaneous thickening and digestion process via forward osmosis membrane. WATER RESEARCH 2024; 254:121378. [PMID: 38430758 DOI: 10.1016/j.watres.2024.121378] [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: 01/14/2024] [Revised: 02/22/2024] [Accepted: 02/23/2024] [Indexed: 03/05/2024]
Abstract
This study delved into the efficacy of sludge digestion and the mechanisms involved in sludge destruction during the implementation of forward osmosis process for sludge thickening and digestion (FO-MSTD). Utilizing a lab-scale FO membrane reactor for the thickening and digestion of waste activated sludge (WAS), the investigation explored the effects of sludge thickening and digestion in FO-MSTD processes using draw solutions of varying concentrations. The findings underscored the significance of hydraulic retention time (HRT) as a pivotal parameter influencing the swift thickening or profound digestion of sludge. Consequently, tailoring the HRT to specific processing objectives emerged as a key strategy for achieving desired treatment outcomes. In the investigation, the use of a 1 M NaCl draw solution in the FO-MSTD process showcased enhanced thickening and digestion capabilities. This specific setup raised the concentration of mixed liquor suspended solids (MLSS) to over 30 g/L and achieved a 42.7% digestion efficiency of mixed liquor volatile suspended solids (MLVSS) within an operational timeframe of 18 days. Furthermore, the research unveiled distinct stages in the sludge digestion process of the FO-MSTD system, characterized by fully aerobic digestion and aerobic-local anaerobic co-existing digestion. In the fully aerobic digestion stage, the sludge digestion rate exhibited a steady increase, leading to the breakdown of sludge floc structures and the release of a substantial amount of nutrients into the sludge supernatant. The predominant microorganisms during this stage were typical functional microorganisms found in wastewater treatment systems. Transitioning into the aerobic-local anaerobic co-existing digestion stage, both MLSS concentration and MLVSS digestion efficiency continued to rise, accompanied by a decreasing dissolved oxygen (DO) concentration. More organic matter was released into the supernatant, and sludge microbial flocs tended to reaggregate. The localized anaerobic environment within the FO-MSTD reactor fostered an increase in the relative abundance of bacteria with nitrogen and phosphorus removal functions, thereby positively impacting the mitigation of total nitrogen (TN) and total phosphorus (TP) concentrations in the sludge supernatant. The results of this research enhance comprehension of the advanced FO-MSTD technology in the treatment of WAS.
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Affiliation(s)
- Xiawen Yi
- Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Ecology, Jiangnan University, Wuxi 214122, PR China
| | - Zhiwei Wang
- School of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China
| | - Pin Zhao
- Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Ecology, Jiangnan University, Wuxi 214122, PR China
| | - Weilong Song
- Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Ecology, Jiangnan University, Wuxi 214122, PR China
| | - Xinhua Wang
- Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Ecology, Jiangnan University, Wuxi 214122, PR China; Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, Suzhou University of Science and Technology, Suzhou 215009, PR China.
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Zambrano-Romero A, Ramirez-Villacis DX, Barriga-Medina N, Sierra-Alvarez R, Trueba G, Ochoa-Herrera V, Leon-Reyes A. Comparative Methods for Quantification of Sulfate-Reducing Bacteria in Environmental and Engineered Sludge Samples. BIOLOGY 2023; 12:985. [PMID: 37508415 PMCID: PMC10375983 DOI: 10.3390/biology12070985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 06/28/2023] [Accepted: 07/06/2023] [Indexed: 07/30/2023]
Abstract
This study aimed to compare microscopic counting, culture, and quantitative or real-time PCR (qPCR) to quantify sulfate-reducing bacteria in environmental and engineered sludge samples. Four sets of primers that amplified the dsrA and apsA gene encoding the two key enzymes of the sulfate-reduction pathway were initially tested. qPCR standard curves were constructed using genomic DNA from an SRB suspension and dilutions of an enriched sulfate-reducing sludge. According to specificity and reproducibility, the DSR1F/RH3-dsr-R primer set ensured a good quantification based on dsrA gene amplification; however, it exhibited inconsistencies at low and high levels of SRB concentrations in environmental and sulfate-reducing sludge samples. Ultimately, we conducted a qPCR method normalized to dsrA gene copies, using a synthetic double-stranded DNA fragment as a calibrator. This method fulfilled all validation criteria and proved to be specific, accurate, and precise. The enumeration of metabolically active SRB populations through culture methods differed from dsrA gene copies but showed a plausible positive correlation. Conversely, microscopic counting had limitations due to distinguishing densely clustered organisms, impacting precision. Hence, this study proves that a qPCR-based method optimized with dsrA gene copies as a calibrator is a sensitive molecular tool for the absolute enumeration of SRB populations in engineered and environmental sludge samples.
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Affiliation(s)
- Aracely Zambrano-Romero
- Instituto de Microbiología, Universidad San Francisco de Quito USFQ, Campus Cumbayá, Diego de Robles y Vía Interoceánica, Quito 17-1200-841, Ecuador
| | - Dario X Ramirez-Villacis
- Instituto de Microbiología, Universidad San Francisco de Quito USFQ, Campus Cumbayá, Diego de Robles y Vía Interoceánica, Quito 17-1200-841, Ecuador
- Colegio de Ciencias e Ingeniería, Universidad San Francisco de Quito USFQ, Campus Cumbayá, Diego de Robles s/n y Vía Interoceánica, Quito 17-1200-841, Ecuador
- Laboratorio de Biotecnología Agrícola y de Alimentos, Ingeniería en Agronomía, Colegio de Ciencias e Ingenierías, Universidad San Francisco de Quito USFQ, Campus Cumbayá, Diego de Robles y Vía Interoceánica, Quito 17-1200-841, Ecuador
| | - Noelia Barriga-Medina
- Colegio de Ciencias e Ingeniería, Universidad San Francisco de Quito USFQ, Campus Cumbayá, Diego de Robles s/n y Vía Interoceánica, Quito 17-1200-841, Ecuador
- Laboratorio de Biotecnología Agrícola y de Alimentos, Ingeniería en Agronomía, Colegio de Ciencias e Ingenierías, Universidad San Francisco de Quito USFQ, Campus Cumbayá, Diego de Robles y Vía Interoceánica, Quito 17-1200-841, Ecuador
| | - Reyes Sierra-Alvarez
- Department of Chemical and Environmental Engineering, The University of Arizona, P.O. Box 210011, Tucson, AZ 85721-0011, USA
| | - Gabriel Trueba
- Instituto de Microbiología, Universidad San Francisco de Quito USFQ, Campus Cumbayá, Diego de Robles y Vía Interoceánica, Quito 17-1200-841, Ecuador
| | - Valeria Ochoa-Herrera
- Colegio de Ciencias e Ingeniería, Universidad San Francisco de Quito USFQ, Campus Cumbayá, Diego de Robles s/n y Vía Interoceánica, Quito 17-1200-841, Ecuador
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280, USA
| | - Antonio Leon-Reyes
- Colegio de Ciencias e Ingeniería, Universidad San Francisco de Quito USFQ, Campus Cumbayá, Diego de Robles s/n y Vía Interoceánica, Quito 17-1200-841, Ecuador
- Laboratorio de Biotecnología Agrícola y de Alimentos, Ingeniería en Agronomía, Colegio de Ciencias e Ingenierías, Universidad San Francisco de Quito USFQ, Campus Cumbayá, Diego de Robles y Vía Interoceánica, Quito 17-1200-841, Ecuador
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280, USA
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De Carluccio M, Sabatino R, Eckert EM, Di Cesare A, Corno G, Rizzo L. Co-treatment of landfill leachate with urban wastewater by chemical, physical and biological processes: Fenton oxidation preserves autochthonous bacterial community in the activated sludge process. CHEMOSPHERE 2023; 313:137578. [PMID: 36529163 DOI: 10.1016/j.chemosphere.2022.137578] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 12/02/2022] [Accepted: 12/14/2022] [Indexed: 06/17/2023]
Abstract
The impact of Fenton oxidation (FO) and Air stripping (AS) pre-treatments on the bacterial community of a biological activated sludge (B-AS) process for the co-treatment of mature landfill leachate (MLL) and urban wastewater (UWW) was assessed. In this work high-throughput sequencing was used to identify changes in the composition of the bacterial communities when exposed to different landfill leachate's pre-treatments. The combination of FO and AS to increase biodegradability (BOD5/COD) and reduce ammonia concentration (NH3) respectively, allowed to successfully operate the B-AS and effectively treat MLL. In particular, BOD5/COD resulted to be the key factor for bacterial community shifting. The microbiological community of the B-AS, mainly composed by the phylum Bacteroidota (Saprospiraceae, PHOS-HE51, Chitinophagaceae) after FO pre-treatment, shifted to Pseudomonadota (Caulobacteraceae and Hyphomicrobiaceae) when FO was not used. At the same time a drastic reduction in BOD5 removal was observed (90%-58%). On the other hand, high NH3 concentration affected the abundance of the family Saprospiraceae, known to play a key role in the degradation of complex organic compounds in B-AS. The results obtained suggest that a suitable combination of pre-treatments can reduce the negative effect of MLL on the B-AS process, reducing the pressure on autochthonous bacteria and therefore the acclimatization time of the biological process.
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Affiliation(s)
- Marco De Carluccio
- Water Science and Technology Group (WaSTe), Department of Civil Engineering, University of Salerno, Via Giovanni Paolo II 132, 84084, Fisciano SA, Italy
| | - Raffaella Sabatino
- Water Research Institute (IRSA) - MEG Molecular Ecology Group, CNR - National Research Council of Italy, Largo Tonolli 50, 28922, Verbania, Italy
| | - Ester M Eckert
- Water Research Institute (IRSA) - MEG Molecular Ecology Group, CNR - National Research Council of Italy, Largo Tonolli 50, 28922, Verbania, Italy
| | - Andrea Di Cesare
- Water Research Institute (IRSA) - MEG Molecular Ecology Group, CNR - National Research Council of Italy, Largo Tonolli 50, 28922, Verbania, Italy
| | - Gianluca Corno
- Water Research Institute (IRSA) - MEG Molecular Ecology Group, CNR - National Research Council of Italy, Largo Tonolli 50, 28922, Verbania, Italy
| | - Luigi Rizzo
- Water Science and Technology Group (WaSTe), Department of Civil Engineering, University of Salerno, Via Giovanni Paolo II 132, 84084, Fisciano SA, Italy.
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