Significance of Physical Parameters of Coagulation-Flocculation in Water Treatment with Moringa Oleifera

摘要

Rapid and slow mixing of coagulant with the waterto be treated are the steps in the process of coagulation-flocculation. There are several factors, both physical and chemical, which influence the process of coagulation-flocculation. Design criteria suggest that the principal parameters of rapid mix and slow mix for the purpose of design and functional evaluation are velocity gradient and time of mixing. The shape of the mixing unit and the baffles into it also affect the process of coagulation-flocculation. Also the turbidity and nature of turbidity have influence on effective turbidity removal. The experiments were performed to study the significance of type of turbidity, shape of mixing unit and the baffles into it, velocity gradient and time of mixing on turbidity removal. The herbal coagulant Moringa oleifera and its various forms were used in the study. The experiments were performed using two types of clay turbidities with 50 NTU, 150 NTU and 450 NTU turbidity value. The circular baffled jar was found to be most efficient for turbidity removal. The rapid mix velocity gradient of 720 s(-1) and slow mix velocity gradient of 90 s~(-1) gave the maximum turbidity removal efficiency.