Integrating Fluorescent Dye Flow‐Curve Testing and Acoustic Doppler Velocimetry Profiling for In Situ Hydraulic Evaluation and Improvement of Clarifier Performance

Abstract

Enhancing the performance of clarifiers requires a thorough understanding of their hydraulics. Fluorescence spectroscopy and acoustic doppler velocimeter (ADV) profiling generally have been used separately to evaluate secondary settlers. We propose that simultaneous use of these techniques is needed to obtain a more reliable and useful evaluation. Experiments were performed on laboratory-and full-scale clarifiers. Factors affecting Fluorescein and Rhodamine 6G properties were identified. Underestimations up to 500% in fluorescence intensities may be derived from differential fluorescence quenching by oxygen. A careful control and interpretation of fluorescent dye experiments is needed to minimize artifacts in real settings. While flowcurve tests constructed under controlled conditions provided a more accurate overall quantitative estimation of the hydraulic performance, ADV velocity and turbulence profiling provided a detailed spatial understanding of flow patterns that was used to troubleshoot and fix the causes of hydraulic short-circuits. Water Environ. Res., 82, 675 (2010).

Photocatalytic Degradation of Aqueous Rhodamine 6G Using Supported TiO2 Catalysts. A Model for the Removal of Organic Contaminants From Aqueous Samples

“…Rhodamine 6G is a cationic polar dye with a rigid heterocyclic structure, which exhibits a strong absorption in the visible and an intense fluorescence (Magde et al, 1999;Bujdak and Iyi, 2012;Zehentbauer et al, 2014). Rh6G is widely used in acrylic, nylon, silk, wool and dyeing, it is the dye most used for dye laser applications and as a fluorescent tracer to visualize flow patterns as for example in the field of hydraulics (Tarud et al, 2010). Rh6G is commonly used as a sensitizer (Wu et al, 1998).…”

Concentration profiling of a horizontal sedimentation tank utilising a bespoke acoustic backscatter array and CFD simulations

“…For flow characteristics, in situ measurements can be achieved through techniques such as Doppler profilers (Mohanarangam et al, 2013;Tarud et al, 2010;Vanrolleghem et al, 2006). In terms of particle property measurement, while image analysers (Concha et al, 2017;Derlon et al, 2017) and focused beam reflectance monitors (De Clercq et al, 2004;Farrow et al, 2000) have been utilised to measure particle size or shape, characterising the settling dynamics within sludge settling zones is generally achieved only through interfacial sludge blanket monitors (Schewerda et al, 2013).…”