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Stricker M, Littfinski T, Heinz E, Pecher KH, Lübken M, Grüning H, Wichern M. Design-oriented evaluation of the hydrodynamics in a full-scale combined filter-lamella separator for urban stormwater treatment. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2022; 85:2854-2868. [PMID: 35638792 DOI: 10.2166/wst.2022.135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The development of compact treatment devices with high removal efficiencies and low space requirements is a key objective of urban stormwater treatment. Thus, many devices utilize a combination of sedimentation and upward flow filtration in a single system. This study, for the first time, evaluates the flow field inside a combined filter-lamella separator via computational fluid dynamics. Herein, three objectives are investigated: (i) the flow field for different structural configurations, (ii) the distribution of particulate matter along the filter bed and (iii) the dynamic clogging in discrete filter zones, which is addressed by a clogging model derived from literature data. The results indicate that a direct combination of a filtration stage with a lamella separator promotes a uniform flow distribution. The distribution of particulate matter along the filter bed varies with configuration and particle size. Clogging, induced by particles in the spectrum <63 μm, creates gradients of hydraulic conductivity along the filter bed. After treating about half of Germany's annual runoff-efficient precipitation at a rainfall intensity of 5 L/(s·ha), the filtration rates increase in the front of the filter bed by +10%. Thus, long-term operating behavior is sensitive to efficient filter utilization in compact treatment devices.
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Affiliation(s)
- Max Stricker
- Department of Civil and Environmental Engineering, Institute of Urban Water Management and Environmental Engineering, Ruhr-Universität Bochum, Universitätsstraße 150, Bochum 44801, Germany E-mail:
| | - Tobias Littfinski
- Department of Civil and Environmental Engineering, Institute of Urban Water Management and Environmental Engineering, Ruhr-Universität Bochum, Universitätsstraße 150, Bochum 44801, Germany E-mail:
| | - Eva Heinz
- Department of Civil and Environmental Engineering, Institute of Urban Water Management and Environmental Engineering, Ruhr-Universität Bochum, Universitätsstraße 150, Bochum 44801, Germany E-mail:
| | | | - Manfred Lübken
- Department of Civil and Environmental Engineering, Institute of Urban Water Management and Environmental Engineering, Ruhr-Universität Bochum, Universitätsstraße 150, Bochum 44801, Germany E-mail:
| | - Helmut Grüning
- Faculty of Energy, Building Services, Environmental Engineering, University of Applied Sciences Münster, Stegerwaldstraße 39, Steinfurt 48565, Germany
| | - Marc Wichern
- Department of Civil and Environmental Engineering, Institute of Urban Water Management and Environmental Engineering, Ruhr-Universität Bochum, Universitätsstraße 150, Bochum 44801, Germany E-mail:
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Björklund K, Li LY. Adsorption of organic stormwater pollutants onto activated carbon from sewage sludge. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2017; 197:490-497. [PMID: 28412620 DOI: 10.1016/j.jenvman.2017.04.011] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 10/14/2016] [Accepted: 04/05/2017] [Indexed: 05/07/2023]
Abstract
Adsorption filters have the potential to retain suspended pollutants physically, as well as attracting and chemically attaching dissolved compounds onto the adsorbent. This study investigated the adsorption of eight hydrophobic organic compounds (HOCs) frequently detected in stormwater - including four polycyclic aromatic hydrocarbons (PAHs), two phthalates and two alkylphenols - onto activated carbon produced from domestic sewage sludge. Adsorption was studied using batch tests. Kinetic studies indicated that bulk adsorption of HOCs occurred within 10 min. Sludge-based activated carbon (SBAC) was as efficient as tested commercial carbons for adsorbing HOCs; adsorption capacities ranged from 70 to 2800 μg/g (Cinitial = 10-300 μg/L; 15 mg SBAC in 150 mL solution; 24 h contact time) for each HOC. In the batch tests, the adsorption capacity was generally negatively correlated to the compounds' hydrophobicity (log Kow) and positively associated with decreasing molecule size, suggesting that molecular sieving limited adsorption. However, in repeated adsorption tests, where competition between HOCs was more likely to occur, adsorbed pollutant loads exhibited strong positive correlation with log Kow. Sewage sludge as a carbon source for activated carbon has great potential as a sustainable alternative for sludge waste management practices and production of a high-capacity adsorption material.
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Affiliation(s)
- Karin Björklund
- Department of Civil Engineering, University of British Columbia, 6250 Applied Science Lane, Vancouver, B.C, V6T 1Z4, Canada; Department of Civil and Environmental Engineering, Chalmers University of Technology, Sven Hultins Gata 8, 41296 Göteborg, Sweden.
| | - Loretta Y Li
- Department of Civil Engineering, University of British Columbia, 6250 Applied Science Lane, Vancouver, B.C, V6T 1Z4, Canada
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