New optical method for water treatment control

A photosedimentation method for floc characterization was developed combining gravitational settling with photoelectric measurements. Settling particles cross a light beam that illuminates a detection system. The attenuation of the beam is related to the projected area of the particles and so the particle size distribution can be determined. When a floc crosses the beam the amount of light reaching the detector is reduced.The signal from the detection system is sent to the data acquisition system. Voltage/time signals are analyzed in order to produce the physical characteristics of flocs. Different detection systems were tested with a single or a double photodiode. Calibration tests were performed with glass beads of known physical characteristics and kaolin and silica suspensions were used for simulation tests. different experimental conditions of floc formation (mixing conditions and polymer concentration) were changed and the corresponding floc characteristics were calculated.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.