Abstract
Currently, industries seek to optimize the development of technology from energy-saving, economic, and environmental perspectives. Dissolved air flotation (DAF) is one of the most effective wastewater treatment systems. However, it requires considerable energy and causes significant operating costs. A recently emerged application of using fluidic oscillators (FOs) to generate microbubbles has attracted extensive attention, as it consumes much less energy and has proven to be a more energy-efficient technique. In this article, a microbubble generator based on FOs is introduced into the flotation tank, and an energy-saving water treatment system, namely fluidic air flotation (FAF), is presented. Using the computational fluid dynamics (CFD) method, the flow pattern of the FAF is investigated. It is observed that FAF generates a dynamic flow pattern, which is beneficial for bubble removal. At the upper part of the separation zone, the flow pattern exhibits a wavy shape. The flow pattern at the lower part switches between clockwise and counterclockwise. The air distribution of the separation zone is also studied. It is found that the height of the “white water” zone almost linearly decreases with the increase in bubble diameter and diffuser size. FAF consumes almost no energy and occupies a small area, and it is expected to provide a promising solution to develop a new generation of the wastewater treatment system.
Highlights
The dissolved air flotation (DAF) system has been extensively used in the wastewater treatment field [1,2,3]
The coalescence model had a significant impact on air distribution, but unexpected behavior was observed; namely, the microbubbles did not distribute throughout the height of the separation zone
Lee et al [1] investigated the influence of turbulence models on the internal flow behavior inside a DAF tank, and it was found that the realizable k − ε model resulted in greater agreement with the experimental results
Summary
The dissolved air flotation (DAF) system has been extensively used in the wastewater treatment field [1,2,3]. It was presented that a dead area was observed under the sloping baffle, which had a negative effect on water purification [13,14] Another common approach to generate bubbles is to inject air into a diffuser with very small orifices [12]. Based on FOs, Zimmerman et al [21] designed a bespoke experimental rig that adopted the flexible membrane diffuser network and achieved conventional aeration for a tank with a 30 m3/h throughput They illustrated that this kind of microbubble generator is a promising component of wastewater treatment. A new wastewater treatment system composed of an oscillating air jet and DAF tank is presented It is called fluidic air flotation (FAF) in this paper. The results of this study are anticipated to enrich our understanding of the switching mechanism of FAF and offer references for effectively designing water treatment systems
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
