Diffused Air Flotation (DAF) has been successfully used for removal of
turbidity in water treatment plants through numerous applications. The
optimization of the system is dependent of several factors such as coagulant
dose, flocculation time, and waterbed depth along the separation zone of the
DAF. This paper addresses mainly the effect of bubble bed depth in the
separation column on turbidity removal from water. Effects of varying
alum coagulant dose from 5 to 45mgll and changing the influent hydraulic
loading from 1 to 4 m3/m2ihr on DAF performance were also addressed.
Results showed increased efficiency of turbidity removal with the increase
of bubble depth in the separation column, as fewer particles were dragged
out from the process effluent port situated at the bottom of the tank. The
increase in hydraulic loading though beneficial in reducing the required
surface area resulted in increased turbidity in the treated effluent.