Dissolved air flotation (DAF) has received more attention recently as a separation technique in both drinking water as well as wastewater treatment. However, the process as well as the preceding flocculation step is complex and not completely understood. Given the multiphase nature of the process, fluid dynamics studies are important to understand and optimize the DAF system in terms of operation and design. The present study is intended towards a comprehensive computational analysis for design optimization of the treatment plant in Kluizen, Belgium. Setting up the modelling framework involving the multiphase flow problem is briefly discussed. 3D numerical simulations on a scaled down model of the DAF design were analysed. The flow features give better confidence, but the flocs escape through the outlet still prevails which is averse to the system performance. In order to improve the performance and ease of maintenance, design modifications have been proposed by using a perforated tube for water extraction and are found to be satisfactory. The discussion is further reinforced through validating the numerical model against the experimental findings for stratified flow conditions.
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http://dx.doi.org/10.2166/wst.2020.028 | DOI Listing |
Nat Commun
December 2024
Key Laboratory of Molecular Nanostructure and Nanotechnology, Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China.
Zn-air batteries (ZABs) present high energy density and high safety but suffer from low oxygen reaction reversibility and dendrite growth at Zn electrode in alkaline electrolytes. Non-alkaline electrolytes have been considered recently for improving the interfacial processes in ZABs. However, the dynamic evolution and reaction mechanisms regulated by electrolytes at both the positive and Zn negative electrodes remain elusive.
View Article and Find Full Text PDFLangmuir
December 2024
Institute of Physics, Academia Sinica, Nankang, Taipei 115, Taiwan.
In the present study, we deposited buffer solutions containing hydrophobic (GA) fibrils onto highly oriented pyrolytic graphite (HOPG) and imaged the surfaces through atomic force microscopy (AFM). Within 3 h of applying ambient (nondegassed) buffers, we observed the formation of two-dimensional stripe-like domains on the HOPG surfaces surrounding the (GA) fibrils. However, these stripe domains did not form under degassed buffers.
View Article and Find Full Text PDFHuan Jing Ke Xue
January 2025
National Engineering Laboratory of Urban Sewage Advanced Treatment and Resource Utilization Technology, Faculty of Architecture, Civil and Transportation Engineering, Beijing University of Technology, Beijing 100124, China.
To achieve non-carbon dioxide greenhouse gas emission reduction and control in municipal wastewater treatment plants (WWTPs), this study conducted one-year long-term monitoring of nitrous oxide (NO) in the anaerobic-anoxic-aerobic (AO) process of a large-scale municipal wastewater treatment plant in Beijing. The experimental results showed that the anaerobic and anoxic zones of the AO process could effectively remove dissolved NO contained in the return sludge, while the aerobic zone was the main area for NO generation and emission, and its generation pathway may have been dominated by ammonia oxidizing bacteria (AOB) denitrification. A significant difference was observed between winter and summer NO production, and the difference in the average NO release flux was up to 7.
View Article and Find Full Text PDFWater Res
December 2024
Faculty of Applied Science, School of Engineering, University of British Columbia Okanagan Campus, Kelowna, British Columbia V1V 1V7, Canada.
In this research, a sustainable blue-green infrastructure (BGI) was developed to efficiently remove contaminants from stormwater through a combined use of modified porous asphalt (PA) and microalgae cultivation to provide a potential drinking water (DW) source. According to the results, the modified PA with powder activated carbon (PAC) could successfully reduce the level of total suspended solids (TSS), turbidity, polycyclic aromatic hydrocarbons (PAHs), oil and grease to below the DW standards but failed to efficiently remove some heavy metals (HMs) and nutrient pollutants. The results revealed that the treated stormwater was an appropriate medium for microalgae cultivation.
View Article and Find Full Text PDFWei Sheng Yan Jiu
November 2024
Shanghai University of Medicine & Health Sciences, Shanghai 200237, China.
Objective: To investigate the protective effect of lycopene on lung oxidative damage induced by atmospheric fine particulate matter(PM_(2.5)) in rats.
Methods: Sixty 7-week-old male Sprague-Dawley rats were randomly divided into six groups: normal control group, PM_(2.
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