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Luo J, Xia X, Li Y, Fang S, Wang F, Cheng X, Feng L, Huang W, Wu Y. Distinct effects of chemical- and bio- flocculants on the sludge acidogenic fermentation for volatile fatty acids production by affecting the acidogenic steps, microbial community structure and metabolic functions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 905:167207. [PMID: 37730033 DOI: 10.1016/j.scitotenv.2023.167207] [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: 07/11/2023] [Revised: 08/30/2023] [Accepted: 09/17/2023] [Indexed: 09/22/2023]
Abstract
Flocculants play crucial roles in sludge treatment, while the specific impact of chemical and bio-flocculants on sludge anaerobic fermentation was unknown. This study unveiled the contrasting effects of chitosan (CTS) and poly‑aluminum chloride (PAC) on volatile fatty acids (VFAs) generation during sludge fermentation. CTS supplementation resulted in 17.2 % increase in VFAs production, while PAC exposure led to 7.6 % reduction compared to the control. Further investigation revealed that CTS facilitated sludge solubilization and hydrolysis, thus providing sufficient organic substrates for VFAs generation. Additionally, environmental-friendly CTS exposure positively influenced the abundance and activity of functional anaerobes, as well as the expression of genes associated with VFAs biosynthesis. In contrast, PAC exposure resulted in the formation of larger sludge flocs, which hindered WAS solubilization and hydrolysis. Meanwhile, its potential microbial toxicity also impeded the microbial metabolic activity (i.e., genetic expressions), resulting in unsatisfactory VFAs production.
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Affiliation(s)
- Jingyang Luo
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, China; College of Environment, Hohai University, Nanjing 210098, China
| | - Xue Xia
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, China; College of Environment, Hohai University, Nanjing 210098, China
| | - Yuxiao Li
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, China; College of Environment, Hohai University, Nanjing 210098, China
| | - Shiyu Fang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, China; College of Environment, Hohai University, Nanjing 210098, China
| | - Feng Wang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, China; College of Environment, Hohai University, Nanjing 210098, China
| | - Xiaoshi Cheng
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, China; College of Environment, Hohai University, Nanjing 210098, China
| | - Leiyu Feng
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Wenxuan Huang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, China; College of Environment, Hohai University, Nanjing 210098, China.
| | - Yang Wu
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
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2
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Ossiansson E, Bengtsson S, Persson F, Cimbritz M, Gustavsson DJI. Primary filtration of municipal wastewater with sludge fermentation - Impacts on biological nutrient removal. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 902:166483. [PMID: 37611717 DOI: 10.1016/j.scitotenv.2023.166483] [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: 06/08/2023] [Revised: 08/18/2023] [Accepted: 08/20/2023] [Indexed: 08/25/2023]
Abstract
Primary filtration is a compact pre-treatment process for municipal wastewater, which can lead to high removal of total suspended solids (TSS) if polymer is added prior to filtration. Extensive carbon removal with rotating belt filter (RBF) can be combined with filter primary sludge fermentation at ambient temperature, in order to produce volatile fatty acids (VFAs) as carbon source for biological nutrient removal (BNR). This process was implemented at large pilot-scale and operated for more than a year. The results showed that the RBF efficiently removed particles >10 μm, and that the TSS removal had a strong linear correlation to the influent TSS concentration. Fermentation of the sludge at ambient temperature and five days retention time and addition of the fermentate to the wastewater could nearly double the VFA concentration in the wastewater by adding 31 ± 9 mg VFA-COD/L. Meanwhile, an increase of 2 mg/L of ammonium nitrogen, and 0.7 mg /L of phosphate phosphorus would be added to the wastewater with the fermentate. Adding the fermented sludge to the wastewater stream and removing the particles with RBF makes it possible to utilize nearly all the produced VFAs for BNR, and the feasibility of this configuration was shown at pilot-scale. According to simulations of subsequent BNR, the pre-treatment would lead to lower effluent total nitrogen concentrations. Alternatively, the required BNR volume could be reduced by 11-18 %. The estimated total biogas production was similar for pre-treatment with primary settler and RBF with fermentation. RBF without fermentation gave the most favourable energy balance, but did not reach the same low effluent value for total nitrogen as RBF with fermentation.
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Affiliation(s)
- Elin Ossiansson
- VA SYD, Box 191, SE-20121 Malmö, Sweden; Chalmers University of Technology, Dep. of Architecture and Civil Engineering, SE-412 96 Gothenburg, Sweden.
| | - Simon Bengtsson
- VA SYD, Box 191, SE-20121 Malmö, Sweden; Sweden Water Research, Scheelevägen 15, SE-22370 Lund, Sweden.
| | - Frank Persson
- Chalmers University of Technology, Dep. of Architecture and Civil Engineering, SE-412 96 Gothenburg, Sweden.
| | - Michael Cimbritz
- Lund University, Dep. of Chemical Engineering, Box 124, SE-221 00 Lund, Sweden.
| | - David J I Gustavsson
- VA SYD, Box 191, SE-20121 Malmö, Sweden; Sweden Water Research, Scheelevägen 15, SE-22370 Lund, Sweden.
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3
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Ossiansson E, Persson F, Bengtsson S, Cimbritz M, Gustavsson DJI. Seasonal variations in acidogenic fermentation of filter primary sludge. WATER RESEARCH 2023; 242:120181. [PMID: 37343334 DOI: 10.1016/j.watres.2023.120181] [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: 04/05/2023] [Revised: 06/01/2023] [Accepted: 06/06/2023] [Indexed: 06/23/2023]
Abstract
Primary treatment of municipal wastewater by rotating belt filtration followed by hydrolysis and acidogenic fermentation of the filter primary sludge (FPS) at ambient temperature was studied at pilot-scale during one year. The seasonal variations of volatile fatty acids (VFAs), nutrient release and soluble COD production as well as microbial community assembly were assessed, leading to novel findings for fermentation at ambient temperature. The reproducibility of VFA production performance was first established by operating the two fermentation reactors under the same conditions, showing similar results regarding VFA production and microbial community structure. One year of operation at 5 d retention time (RT) and 16-29 °C resulted in an average VFA yield of 180±35 mg COD/g VSin and soluble COD yield of 242±40 mg COD/g VSin. The VFA formation was temperature-dependent, with ϴ=1.033±0.005 ( [Formula: see text] . The seasonal variations of the acetic and propionic acid productions were pronounced, whereas the productions of VFAs with longer chains were more stable regardless of temperature. The community structure of the reactor microbiomes was also clearly affected by season and temperature and linked with the production spectrum of VFAs. The ammonium and phosphate releases were stable during the year, leading to a decrease in ratios of soluble COD to NH4+-N and PO43--P during winter. The soluble COD yield was 11% and 27% higher at 5 d RT compared to 3 and 2 d RT respectively, but the corresponding volumetric productivities were lower. The dissimilarities between microbiomes in influent FPS and fermenters were significant even at a short RT of 2 d, and increased with longer RT of 3 and 5 d, primarily caused by selection of bacteria within Bacteroidota in the fermentation reactors.
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Affiliation(s)
- Elin Ossiansson
- VA SYD, Box 191, SE-20121 Malmö, Sweden; Chalmers University of Technology, Dep. of Architecture and Civil Engineering, SE-412, 96 Gothenburg, Sweden.
| | - Frank Persson
- Chalmers University of Technology, Dep. of Architecture and Civil Engineering, SE-412, 96 Gothenburg, Sweden
| | - Simon Bengtsson
- VA SYD, Box 191, SE-20121 Malmö, Sweden; Sweden Water Research, Scheelevägen 15, SE-22370 Lund, Sweden
| | - Michael Cimbritz
- Lund University, Dep. of Chemical Engineering, Box 124, SE-221 00 Lund, Sweden
| | - David J I Gustavsson
- VA SYD, Box 191, SE-20121 Malmö, Sweden; Sweden Water Research, Scheelevägen 15, SE-22370 Lund, Sweden
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4
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Diaz R, Goswami A, Clark HC, Michelson R, Goel R. Volatile fatty acid production from primary and secondary sludges to support efficient nutrient management. CHEMOSPHERE 2023:138984. [PMID: 37315862 DOI: 10.1016/j.chemosphere.2023.138984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 05/16/2023] [Accepted: 05/17/2023] [Indexed: 06/16/2023]
Abstract
Enhanced hydrolysis of sludges during fermentation is an important factor to achieve solubilization of complex carbon sources and increase the amount of soluble COD that microorganisms could use as food during biological nutrient removal processes. This research shows that a combination of mixing, bioaugmentation, and co-fermentation can be used to increase the hydrolysis of sludges and enhanced the production of volatile fatty acids (VFA). Mixing of primary sludge (PS) at 350 revolutions per minute (RPM) during fermentation increased the hydrolysis of the sludge and increased the soluble chemical oxygen demand (sCOD) by 72% compared to no mixing. Mixing also increased the production of VFA by 60% compared to no mixing conditions. PS hydrolysis was also evaluated using bioaugmentation with the bacteria Bacillus amyloliquefacients, a known producer of the biosurfactant surfactin. Results showed that bioaugmentation enhanced the hydrolysis of the PS by increasing the amount of soluble carbohydrates and soluble proteins present in the form of sCOD. Methanogenesis experiments performed with co-fermentation of decanted primary sludge (PS) and raw waste-activated sludge (WAS) at 75:25 and 50:50 ratios displayed a decreased in production of total biogas by 25.58% and 20.95% and a reduction on methane production by 20.00% and 28.76% respectively, compared to co-fermentation of raw sludges. Compared to fermentation of the sludges separately, co-fermentation of PS and WAS increased the production of VFA and it was determined that 50:50 was the optimum co-fermentation ratio for production of VFA while reducing the reintroduction of nutrients produced during the fermentation process to BNR processes.
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Affiliation(s)
- Ruby Diaz
- Civil & Environmental Engineering, University of Utah, Salt Lake City, USA
| | - Anjan Goswami
- Civil & Environmental Engineering, University of Utah, Salt Lake City, USA
| | - Herald C Clark
- Civil & Environmental Engineering, University of Utah, Salt Lake City, USA
| | | | - Ramesh Goel
- Civil & Environmental Engineering, University of Utah, Salt Lake City, USA.
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Kang D, Zhao X, Wang N, Suo Y, Yuan J, Peng Y. Redirecting carbon to recover VFA to facilitate biological short-cut nitrogen removal in wastewater treatment: A critical review. WATER RESEARCH 2023; 238:120015. [PMID: 37146394 DOI: 10.1016/j.watres.2023.120015] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 04/24/2023] [Accepted: 04/27/2023] [Indexed: 05/07/2023]
Abstract
Wastewater treatment plants (WWTPs) are facing a great challenge to transition from energy-intensive to carbon-neutral and energy-efficient systems. Biological nutrient removal (BNR) can be severely impacted by carbon limitation, particularly for wastewater with a low carbon-to-nitrogen (C/N) ratio, which can significantly increase the operational costs. Waste activated sludge (WAS) is a valuable byproduct of WWTPs, as it contains high levels of organic matter that can be utilized to improve BNR management by recovering and reusing the fermentative volatile fatty acids (VFAs). This review provides a comprehensive examination of the recovery and reuse of VFAs in wastewater management, with a particular focus on advancing the preferable biological short-cut nitrogen removal process for carbon-insufficient municipal wastewaters. First, the method of carbon redirection for recovering VFAs was reviewed. Carbon could be captured through the two-stage A/B process or via sludge fermentation with different sludge pretreatment and process control strategies to accelerate sludge hydrolysis and inhibit methanogens to enhance VFA production. Second, VFAs can support the metabolism of autotrophic N-cycling microorganisms involved in wastewater treatment, such as AOB, NOB, anammox, and comammox bacteria. However, VFAs can also cause inhibition at high concentrations, leading to the partition of AOB and NOB; and can promote partial denitrification as an efficient carbon source for heterotrophic denitrifiers. Third, the lab- and pilot-scale engineering practices with different configurations (i.e., A2O, SBR, UASB) were summarized that have shown the feasibility of utilizing the fermentate to achieve superior nitrogen removal performance without the need for external carbon addition. Lastly, the future perspectives on leveraging the relationships between mainstream and sidestream, nitrogen and phosphorus, autotrophs and heterotrophs were given for sustainable and efficient BNR management.
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Affiliation(s)
- Da Kang
- Department of Environmental Engineering, National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, China
| | - Xuwei Zhao
- Department of Environmental Engineering, National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, China
| | - Nan Wang
- Department of Environmental Engineering, National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, China
| | - Yirui Suo
- Department of Environmental Engineering, National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, China
| | - Jiawei Yuan
- Department of Environmental Engineering, National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, China
| | - Yongzhen Peng
- Department of Environmental Engineering, National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, China.
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6
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Yang S, Chang H, Peng Y, Zhang S, Han X, Sun S, Liu J, Zhang L. Advanced nutrient removal and external sludge reduction: Demonstration in a pilot-scale sequencing batch reactor. WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2023; 95:e10837. [PMID: 36683357 DOI: 10.1002/wer.10837] [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: 09/27/2022] [Revised: 12/29/2022] [Accepted: 01/07/2023] [Indexed: 06/17/2023]
Abstract
Although the addition of excess sludge fermentation products to improve nutrient removal from sewage is cost-effective, its application has rarely been demonstrated. In this study, the external sludge was first collected and fermented under a sludge retention time of 10 days, then introduced into SBR with a 1:15 sewage ratio. The results revealed a gradual increase in the nitrite accumulation ratio to 34.7% in the SBR at the end of the oxic stage after 64 days of adding fermented sludge products. In addition, the average effluent total nitrogen and phosphorous decreased to 7.3 and 0.5 mg/L, corresponding to removal efficiencies of 86.7% and 95.5%, respectively. On the other hand, the use of the fermented sludge products as external organic carbon sources in the SBR increased the external sludge reduction ratio to 42.5%. High-throughput sequencing demonstrated that the increase in the endogenous denitrifier community, polyphosphate-accumulating organisms, and fermentation bacteria were the main factors contributing to the increase in nutrient removal and excess sludge reduction. The economic evaluation indicated that the operational cost of the pilot-scale system saves 0.011$/m3 of sewage treated. PRACTITIONER POINTS: Fermented sludge addition effectively enhanced nutrient removal in pilot-scale SBR. Average effluent TN and PO4 3- -P decreased to 7.3 and 0.5 mg/L, respectively. Highest external sludge reduction rate was 42.5% in pilot-scale reactor. Sewage treatment cost can save 0.011$/m3 under advanced nutrient removal.
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Affiliation(s)
- Shenhua Yang
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing, China
- SDIC XinKai Water Environment Investment Co., Ltd, Beijing, China
| | - Haibin Chang
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing, China
| | - Yongzhen Peng
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing, China
| | - Shujun Zhang
- Beijing Drainage Group Co., Ltd (BDG), Beijing, China
| | - Xiaoyu Han
- Beijing Drainage Group Co., Ltd (BDG), Beijing, China
| | - Shihao Sun
- SDIC XinKai Water Environment Investment Co., Ltd, Beijing, China
| | - Jinjin Liu
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing, China
| | - Liang Zhang
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing, China
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7
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Intensification of Acidogenic Fermentation for the Production of Biohydrogen and Volatile Fatty Acids—A Perspective. FERMENTATION-BASEL 2022. [DOI: 10.3390/fermentation8070325] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Utilising ‘wastes’ as ‘resources’ is key to a circular economy. While there are multiple routes to waste valorisation, anaerobic digestion (AD)—a biochemical means to breakdown organic wastes in the absence of oxygen—is favoured due to its capacity to handle a variety of feedstocks. Traditional AD focuses on the production of biogas and fertiliser as products; however, such low-value products combined with longer residence times and slow kinetics have paved the way to explore alternative product platforms. The intermediate steps in conventional AD—acidogenesis and acetogenesis—have the capability to produce biohydrogen and volatile fatty acids (VFA) which are gaining increased attention due to the higher energy density (than biogas) and higher market value, respectively. This review hence focusses specifically on the production of biohydrogen and VFAs from organic wastes. With the revived interest in these products, a critical analysis of recent literature is needed to establish the current status. Therefore, intensification strategies in this area involving three main streams: substrate pre-treatment, digestion parameters and product recovery are discussed in detail based on literature reported in the last decade. The techno-economic aspects and future pointers are clearly highlighted to drive research forward in relevant areas.
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8
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Perez-Esteban N, Vinardell S, Vidal-Antich C, Peña-Picola S, Chimenos JM, Peces M, Dosta J, Astals S. Potential of anaerobic co-fermentation in wastewater treatments plants: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 813:152498. [PMID: 34968594 DOI: 10.1016/j.scitotenv.2021.152498] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/13/2021] [Accepted: 12/13/2021] [Indexed: 05/25/2023]
Abstract
Fermentation (not anaerobic digestion) is an emerging biotechnology to transform waste into easily assimilable organic compounds such as volatile fatty acids, lactic acid and alcohols. Co-fermentation, the simultaneous fermentation of two or more waste, is an opportunity for wastewater treatment plants (WWTPs) to increase the yields of sludge mono-fermentation. Most publications have studied waste activated sludge co-fermentation with food waste or agri-industrial waste. Mixing ratio, pH and temperature are the most studied variables. The highest fermentation yields have been generally achieved in mixtures dominated by the most biodegradable substrate at circumneutral pH and mesophilic conditions. Nonetheless, most experiments have been performed in batch assays which results are driven by the capabilities of the starting microbial community and do not allow evaluating the microbial acclimation that occurs under continuous conditions. Temperature, pH, hydraulic retention time and organic load are variables that can be controlled to optimise the performance of continuous co-fermenters (i.e., favour waste hydrolysis and fermentation and limit the proliferation of methanogens). This review also discusses the integration of co-fermentation with other biotechnologies in WWTPs. Overall, this review presents a comprehensive and critical review of the achievements on co-fermentation research and lays the foundation for future research.
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Affiliation(s)
- N Perez-Esteban
- Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
| | - S Vinardell
- Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
| | - C Vidal-Antich
- Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain; Water Research Institute, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
| | - S Peña-Picola
- Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
| | - J M Chimenos
- Department of Materials Science and Physical Chemistry, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
| | - M Peces
- Department of Chemistry and Bioscience, Centre for Microbial Communities, Aalborg University, Fredrik Bajers Vej 7H, 9220 Aalborg, Denmark
| | - J Dosta
- Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain; Water Research Institute, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
| | - S Astals
- Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain.
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9
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Sun C, Guo L, Zheng Y, Yu D, Jin C, Zhao Y, Yao Z, Gao M, She Z. Effect of mixed primary and secondary sludge for two-stage anaerobic digestion (AD). BIORESOURCE TECHNOLOGY 2022; 343:126160. [PMID: 34678447 DOI: 10.1016/j.biortech.2021.126160] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Revised: 10/12/2021] [Accepted: 10/15/2021] [Indexed: 06/13/2023]
Abstract
As an energy-efficient and eco-friendly sludge treatment process, two-stage anaerobic digestion (AD) is widely employed to recovery biomass energy from waste sludge. However, the effect of primary and secondary sludge for two-stage AD was not clear. In this study, two-stage AD of mixed sludge in different volume ratio was investigated. The maximum cumulative H2 yield (100.5 ml) and CH4 yield (2643.6 ml) were obtained in volume ratio of 1:3 (primary sludge: secondary sludge). In two-phase AD, mixed sludge could induce positive effect on both organics releasing in extracellular polymeric substances (EPS) and the utilization of volatile fatty acids (VFAs). By investigating the compositional characteristics of dissolved organic matters (DOM) through excitation-emission matrix (EEM) coupling with fluorescence regional integration (FRI), it revealed more degradable substances utilization in mixture of sludge. Results from this work suggest that two-phase AD with mixed sludge is efficient for renewable energy recovery.
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Affiliation(s)
- Cheng Sun
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, PR China
| | - Liang Guo
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, PR China; Key Laboratory of Marine Environmental and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, PR China.
| | - Yongkang Zheng
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, PR China
| | - Dan Yu
- QingDao Municipal Engineering Design Research Institute, Qingdao 266100, PR China
| | - Chunji Jin
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, PR China
| | - Yangguo Zhao
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, PR China
| | - Zhiwen Yao
- QingDao Municipal Engineering Design Research Institute, Qingdao 266100, PR China
| | - Mengchun Gao
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, PR China
| | - Zonglian She
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, PR China
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10
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Bahreini G, Elbahrawi M, Elbeshbishy E, Santoro D, Nakhla G. Biological nutrient removal enhancement using fermented primary and rotating belt filter biosolids. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 796:148947. [PMID: 34273832 DOI: 10.1016/j.scitotenv.2021.148947] [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: 04/30/2021] [Revised: 07/06/2021] [Accepted: 07/06/2021] [Indexed: 06/13/2023]
Abstract
This research compared the impact of two primary treatment options (i.e. primary clarification and rotating belt filtration (RBF)) on biological nutrients removal (BNR) process, using sludge fermentation liquid (SFL) as a carbon source. The liquid fraction of both fermented primary and RBF sludges comparably enhanced BNR. Despite the significant contribution of the unpurified SFL to the sharp increase in nutrient levels; i.e. 47%-64% (primary effluent; PE), and 45%-53% (RBF) of the soluble nitrogen and phosphorus loads; readily biodegradable COD and volatile fatty acids (VFAs) fractions of the combined feed increased significantly (2.5-6.1 times), compared to the original feed by additional SFL. Removal efficiencies in the reactors reached 57% (total nitrogen) and 92% (total phosphorus) after addition of SFL. Effluent nitrogen and phosphorus of the two reactors were close in the range of 15 ± 6 mg N/L, and 0.5 ± 0.3 mg P/L, respectively. Kinetics studies showed denitrification rates of 1.3, and 1.13 kg NO3-N/m3.d for primary effluent and RBF effluent-fed reactors, respectively. Phosphorus release rates were 11.7 and 9.7 mg PO4-P/g VSS.h, for primary, and RBF effluents, respectively; showing 20%-22% lower rates in the RBF SFL. Incorporating experimental data into a plant-wide model for a 100 MLD facility receiving typical medium strength wastewater, showed that although primary treatment enhanced the biogas production by 96% (primary clarification) and 62% (RBF) trains; combined fermentation and anaerobic digestion was effective to enhance the biogas production by 59% on average, compared to the base scenario without primary treatment. Additionally, if primary clarification exists, then the addition of fermentation results in additional revenue of C$1890/d in the plant, considering additional revenue of C$2230/d due to VFA generation in contrast to only C$340/d loss due to the reduced methane production.
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Affiliation(s)
- Gholamreza Bahreini
- Department of Civil and Environmental Engineering, Western University, London, ON N6A 5B9, Canada.
| | - Moustafa Elbahrawi
- Department of Civil and Environmental Engineering, Western University, London, ON N6A 5B9, Canada
| | - Elsayed Elbeshbishy
- Civil Engineering Department, Ryerson University, Toronto, ON M5B 2K3, Canada
| | | | - George Nakhla
- Department of Civil and Environmental Engineering, Western University, London, ON N6A 5B9, Canada; Department of Chemical and Biochemical Engineering, Western University, London, ON N6A 5B9, Canada
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11
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Kang X, Liu Y. Performance and mechanism of conductive magnetite particle-enhanced excess sludge anaerobic digestion for biogas recovery. RSC Adv 2021; 11:35559-35566. [PMID: 35493163 PMCID: PMC9043222 DOI: 10.1039/d1ra06236k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 10/13/2021] [Indexed: 01/01/2023] Open
Abstract
The aim of this study was to evaluate the effect of magnetite particles on the anaerobic digestion of excess sludge. The results showed that methane production increased with the increase in magnetite dosage in the range of 0–5 g L−1, and the cumulative methane production increased by 50.1% at a magnetite dosage of 5 g L−1 compared with the blank reactor after 20 days. Simultaneously, numerous volatile fatty acids (VFAs) were produced at high magnetite dosages, providing the required substrates for methanogenesis. The concentration of magnetite addition was positively correlated with methane production, which proved that magnetite was beneficial for the promotion of the conversion of VFAs to methane. Moreover, the degradation efficiencies of proteins and carbohydrates reached 64% and 52.6% at the magnetite dosage of 5 g L−1, respectively, and corresponding activities of protease and coenzyme F420 were 9.03 IU L−1 and 1.652 μmol L−1. In addition, the Methanosaeta and Methanoregula genus were enriched by magnetite, which often participate in direct interspecies electron transfer as electron acceptors. Magnetite particles were applied to excess sludge anaerobic digestion. The methane production and sludge reduction were related to magnetite particle dosage, and the Methanosaeta and Methanoregula involved in the electron transfer were enriched.![]()
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Affiliation(s)
- Xiaorong Kang
- School of Environmental Engineering, Nanjing Institute of Technology Nanjing 211167 PR China +86-18795465873
| | - Yali Liu
- School of Civil Engineering, Nanjing Forestry University Nanjing 210037 PR China
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Wang H, Xu J, Liu Y, Sheng L. Preparation of ceramsite from municipal sludge and its application in water treatment: A review. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 287:112374. [PMID: 33765522 DOI: 10.1016/j.jenvman.2021.112374] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 03/03/2021] [Accepted: 03/07/2021] [Indexed: 06/12/2023]
Abstract
Municipal sludge is a solid waste material, and resource utilization is the optimal way to dispose of this material. The amount of municipal sludge produced in China is large, and it can be used in the preparation of ceramsite. The content of Al2O3 in drinking water treatment sludge is significantly higher than that in wastewater treatment sludge, while the content of K2O, Na2O and MgO in the two kinds of sludge is similar. When sludge is used to prepare ceramsite, the amount of sludge in most raw materials for ceramsite is less than 50%. The bulk density of the prepared sludge ceramsite is less than 1000 kg m-3, and the highest water absorption rate is close to 40%. The leaching content of heavy metals in municipal sludge-based ceramsite is within the standard health safety limit, and heavy metals are better stabilized. The fitting effect of the pseudo-second-order kinetic equation of the dynamic adsorption of sludge ceramsite is obviously better than that of the pseudo-first-order kinetic equation. Sludge ceramsite used in bio-filter media and constructed wetland (CW) substrates is good able to purify wastewater. In the future, the preparation method of municipal sludge ceramsite and purification research of CW substrates based on sludge ceramsite need to be further improved.
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Affiliation(s)
- Hanxi Wang
- State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration / School of Environment, Northeast Normal University, Jingyue Street 2555, Changchun, 130117, Jilin, China.
| | - Jianling Xu
- State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration / School of Environment, Northeast Normal University, Jingyue Street 2555, Changchun, 130117, Jilin, China.
| | - Yunqing Liu
- Key Laboratory of Pollutant Chemistry and Environmental Treatment, College of Chemistry &; Environmental Sciences, Yili Normal University, Jiefang West Road 448, Yining, 835000, Xinjiang, China.
| | - Lianxi Sheng
- State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration / School of Environment, Northeast Normal University, Jingyue Street 2555, Changchun, 130117, Jilin, China.
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