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Wang Z, Zeng Y, Pan Z, Shen L, Zeng B, Teng J, Lin H. A synergistic approach combining computational fluid dynamics simulation with hydrolysis-acidification for dye wastewater treatment. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 368:122100. [PMID: 39126845 DOI: 10.1016/j.jenvman.2024.122100] [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: 11/28/2023] [Revised: 07/19/2024] [Accepted: 08/03/2024] [Indexed: 08/12/2024]
Abstract
Wastewater treatment is effectively conducted using anaerobic biological methods. Nevertheless, the efficiency of these methods can be hindered by challenges like short-circuits and dead zones, particularly in treating persistent contaminants. This work utilized computational fluid dynamics (CFD) simulations to enhance water distribution, ensuring uniform interactions between solid and liquid phases, and thus mitigating issues related to short-circuits and dead zones. Such enhancements notably amplified the anaerobic biological process's efficiency. Furthermore, dye biodegradability was improved through the application of the hydrolysis acidification technique. Optimal hydraulic retention time for the hydrolysis-acidification reactor, established at 9 h, was determined via sludge cultivation and domestication for stable operation. During stable operation, an elevation in effluent volatile fatty acids was observed, alongside a COD removal rate fluctuating between 15% and 29%. Approximately 50% was noted as the rate of color removal. Simultaneously, a noticeable decrease in effluent pH occurred, with total nitrogen removal approximating 8%. An estimated BOD5/COD ratio of 0.32 was recorded. The incorporation of microbial agents led to an enhanced COD removal, ranging from 28% to 33%, thereby stabilizing the effluent BOD5/COD ratio at around 0.35. This research highlights the advantages of optimizing water distribution in anaerobic reactors, particularly when combined with hydrolysis-acidification techniques, effectively addressing issues of short-circuits and dead zones.
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Affiliation(s)
- Zhe Wang
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, China; Key Laboratory of Watershed Earth Surface Processes and Ecological Security, Zhejiang Normal University, Jinhua 321004, China.
| | - Yansha Zeng
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, China; Key Laboratory of Watershed Earth Surface Processes and Ecological Security, Zhejiang Normal University, Jinhua 321004, China.
| | - Zhenxiang Pan
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, China; Key Laboratory of Watershed Earth Surface Processes and Ecological Security, Zhejiang Normal University, Jinhua 321004, China.
| | - Liguo Shen
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, China; Key Laboratory of Watershed Earth Surface Processes and Ecological Security, Zhejiang Normal University, Jinhua 321004, China.
| | - Bizhen Zeng
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, China; Key Laboratory of Watershed Earth Surface Processes and Ecological Security, Zhejiang Normal University, Jinhua 321004, China.
| | - Jiaheng Teng
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, China; Key Laboratory of Watershed Earth Surface Processes and Ecological Security, Zhejiang Normal University, Jinhua 321004, China.
| | - Hongjun Lin
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, China; Key Laboratory of Watershed Earth Surface Processes and Ecological Security, Zhejiang Normal University, Jinhua 321004, China.
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Ortiz A, Díez-Montero R, García J, Khalil N, Uggetti E. Advanced biokinetic and hydrodynamic modelling to support and optimize the design of full-scale high rate algal ponds. Comput Struct Biotechnol J 2021; 20:386-398. [PMID: 35070164 PMCID: PMC8753131 DOI: 10.1016/j.csbj.2021.12.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 12/26/2021] [Accepted: 12/27/2021] [Indexed: 11/22/2022] Open
Abstract
High rate algal ponds (HRAP) are known for their suitability to treat wastewater and to produce microalgal biomass, which can be converted into bioproducts. However, full-scale application of HRAP is still limited to few cases, and design procedures are not consolidated or standardized. In this study, a demonstrative-scale HRAP system for secondary wastewater treatment to be implemented in India (treatment capacity of 50 m3·d-1) has been designed combining conventional dimensioning techniques and advanced modelling tools. The objective of the study was to assist, verify and optimize the conventional dimensioning of the secondary HRAP by means of simulations predicting the behaviour of the system in the specific local conditions under different configurations and operational strategies. Biokinetic modelling and hydrodynamic analysis using Computational Fluid Dynamics (CFD) were carried out. The simulations performed with the biokinetic model showed that the optimal hydraulic retention time to enhance nutrient removal and biomass production is 4 days. For the hydrodynamic modelling, a 3D model of the HRAP was built to simulate the hydrodynamic behaviour of 36 different designs. Simulations allowed quantifying the presence of low velocity zones as well as the land use efficiency of the different designs in terms of the useful area vs. the total occupied area. Two baffles and tear-shapes with a diameter equal to ¼ of the channel width was the most efficient configuration. Moreover, a technical-economic assessment of the system was carried out, resulting in an investment cost of 483 € per population equivalent and an operational cost of 0.19 € per m3 of treated wastewater.
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Affiliation(s)
- Antonio Ortiz
- GEMMA-Group of Environmental Engineering and Microbiology, Department of Civil and Environmental Engineering, Universitat Politècnica de Catalunya-BarcelonaTech. c/ Jordi Girona 1-3, Building D1, E-08034 Barcelona, Spain
| | - Rubén Díez-Montero
- GEMMA-Group of Environmental Engineering and Microbiology, Department of Civil and Environmental Engineering, Universitat Politècnica de Catalunya-BarcelonaTech. c/ Jordi Girona 1-3, Building D1, E-08034 Barcelona, Spain
| | - Joan García
- GEMMA-Group of Environmental Engineering and Microbiology, Department of Civil and Environmental Engineering, Universitat Politècnica de Catalunya-BarcelonaTech. c/ Jordi Girona 1-3, Building D1, E-08034 Barcelona, Spain
| | - Nadeem Khalil
- Department of Civil Engineering, Z H College of Engineering & Technology, Aligarh Muslim University, Aligarh 202001 UP India
| | - Enrica Uggetti
- GEMMA-Group of Environmental Engineering and Microbiology, Department of Civil and Environmental Engineering, Universitat Politècnica de Catalunya-BarcelonaTech. c/ Jordi Girona 1-3, Building D1, E-08034 Barcelona, Spain
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