Measurement of bubble bed depth in dissolved air flotation using a particle counter

Abstract

In the development of dissolved air flotation (DAF) technology, it is noteworthy that higher hydraulic loading rates are achieved while the reactors become deeper resulting in a smaller footprint. One of the reasons for the increased efficiency is claimed to be the deeper bubble bed depth in the flotation separation zone; however, there has been limited research on the characterization of the bubble bed. In this research, a method for locating the bubble bed interface using a commercially available particle counter is presented. The results compared remarkably well with observations by the naked eye at a pilot plant with a transparent acrylic wall. The method is then applied to locate the bubble bed interface at an operating DAF plant in Wonju, Korea. We can observe that the bubble bed profile changes according to the operational conditions and that higher effluent water quality is obtained with a deeper bubble bed. Based on these results, optimization of DAF process might be possible by monitoring the bubble bed profile in the reactor.

Generation of sub-micron (nano) bubbles and characterization of their fundamental properties

“…The induced coalescence method It was found that, when certain design parameters change, the size of generated bubbles gradually decreases. Bubble size was measured by particle counting method (PCM) (2400D, Chemtrac) [6,11], and when 10 μm bubbles were generated, visibly milky colored water was produced as shown in Fig. 1(a).…”

Comparative evaluation of particle separation efficiency based on carbon dioxide and air bubble sizes in flotation separation processes

“…According to Han et al [5], air bubble sizes decrease as the pressure increases but do not change under constant pressure. Bubble volume concentrations (BVC) with changing pressure and temperature can be calculated using mathematical models and measured from the flotation column directly.…”

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

“…The collision of particles and their attachment to one another to form a greater floc is the basis of flocculation (Amjad 2010;Benjamin et al 2013;George et al 2018). 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).…”