Continuous Flocs Image Analyser (C-FIA) For Flocs Dynamics Tracking During Conventional Water Treatment

In this paper an image analyser termed ‘Continuous Floc Image Analyser (C-FIA)’ developed for tracking the dynamics of floc formation, growth and settling during conventional water-treatment (i.e. coagulation, flocculation, and settling processes) is described. The C-FIA is proposed as an alternative to light-beam scattering and signal-based analysers such as Photometric Dispersion Analyser (PDA). A primary configuration of the C-FIA was developed for collecting video recordings of flocs in a flowing suspension of water sample during the treatment process. A MATLAB script was developed to analyse the image data. A Flocculation Index (FI) based on RGB data associated with video frame pixels was calculated as a measure of flocs concentration. The practicality of the C-FIA in comparison with the PDA was tested using jar testing under laboratory conditions for two different surface water samples with contrasting water qualities. The results demonstrated the C-FIA capability to track the floc dynamics during the conventional treatment process using the FI. The C-FIA showed distinct baseline, rapid mixing, flocculation, and settling stages by providing different levels of FI for each stage. The results obtained indicated impacts of light intensity and light beams radiation angle to the photography cell on the resulted FI. This through its effects on the pixels RGB values of the floc images and raw water image used for determining the background FI value. The comparison of the FI data obtained through the C-FIA with the PDA indicates similarity in FI signal trends during process time by either technique. To achieve a more reliable signal with comparable results between experiments, a more advanced configuration with higher consistency in the photography system is needed.