The Relationship Between Particle Size andTurbidity Fluctuations in Coagulation Process

An on-line Nephelometric Turbidimeter Monitoring System (NTMS) was used in this study to measure water turbidity every second. The standard deviation (SD) of the measured turbidity was found proportional to the particle size; a greater turbidity SD indicated larger particle sizes. Also, a video camera (Watec Co Wat-202B) with image analysis (Matrox Inspector V2.2) was used to confirm whether NTMS is suitable for directly applying to particle size analysis. On the other hand, to understand the relationship between SD of the measured turbidity and particle size of the coagulated floc, the Poly Aluminum Chloride (PACl) prepared in laboratory was used as a coagulant in Jar Test to perform a solid-liquid separation study on a high turbidity (100 NTU) synthetic algae water (algae specie: Chlorella sp). The experimental results indicate that for 100 NTU Chlorella sp. suspensions, the NTMS is simple and effective to find the floc size change in flocculation and selection the optimal flocculation conditions.