A Study on the Possibility of Measuring Sludge Sedimentation Using Contrast Detection Characteristics of CdS Photoresistors

Although operators periodically measure the sludge volume index (SVI) to stabilize bioreactor and solid–liquid separation during wastewater treatment process, there is a problem of inconsistency attributed subjective judgment operator. This study aims investigate possibility securing objective data by employing CdS (cadmium–sulfur) photoresistors for SVI measurements. The sedimentation velocity settling was measured using LED (Light Emitting Diode) lights at same level as installed photoresistors. As result experiment, in photoresistors’ installation position H1 H8 (non-flocculent settling), H9 H12 (discrete flocculent settling) H13 H18 (zone compressive 0.594 mm/s, 0.180 mm/s 0.056 respectively. Through this study, it confirmed that measuring possible. If measurement solid matter several measurements enabled future, will be possible develop calculation algorithms SVI.