Applications of column flotation are increasing in the environmental
area, especially in the treatment of oil and grease (removal
from water), metallic ions, de-inking, and suspended solids removal
(Finch, 1995; Filippov et al., 2000; Capponi et al., 2006). This device
facilitates the prompt rise of the aerated flocs to the top (surface)
of the column. Its high hydraulic-load and flux pattern (plug flow)
are the main observed advantages. The float layer at the surface of
the column consists of a mixture of foam and aerated flocs.