CFD-based process optimization of a dissolved air flotation system for drinking water production

Abstract

<jats:title>Abstract</jats:title> <jats:p>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.</jats:p>

Bubble-particle collision efficiency in rotating dissolved air flotation in paper-recycling wastewater treatment: experiments and modeling

“…Several research works show the significant role of the air bubbles' behavior and concentration and their collisions with particles in optimization (Aqing et al 2016;Bahadori et al 2013;Behin & Bahrami 2012;Han et al 2009;Hussain & Idris 2016;Shuofu et al 2020, Shuofu et al 2019). Computational fluid dynamics (CFD) has been used as a suitable tool to simulate the behavior of single or multiphase flows (Bondelind et al, 2010;Bridgeman et al 2009;Raimund et al 2020;Satpathy et al 2020). This technique has been extensively employed for the simulation of the interactions of fluid phases in DAF (Emmanuil et al 2011;Emmanuil et al 2007;Wang et al 2018;Wang et al 2020).…”

Particle removal optimization in rotating dissolved air flotation used in paper‐recycling wastewater treatment

“…Previous studies on DAF have shown that the concentration and behaviour of air bubbles and their collision with particles play an essential role in reaching an optimized condition (Bahadori et al, 2013; Behin & Bahrami, 2012; Chen et al, 2016; Han et al, 2009; Hussain & Idris, 2016; Shuofu et al, 2019, 2020). On the other hand, computational fluid dynamics (CFD) is considered as the best tool for the computational analysis and optimization based on different turbulence models (Bridgeman et al, 2009; Bondelind et al, 2010; Raimund et al, 2020; Satpathy et al, 2020). CFD has been widely used to investigate and simulate the flow behaviour and phase interactions in DAF (Emmanouil et al, 2007, 2011; Wang et al, 2018, 2020).…”