of the suspension and causes bubbles to be nucleated as the pressure decreases which
raise the particles to the surface. The pressure applied produces bubbles which range
from 10 to 100 mm. Dispersed air flotation requires a higher pressure drop for
generating bubbles, and generates bubbles by continuously passing air through a
porous material. While less energy is consumed it is more costly (Moheimani et al.
2015).
1.3.7.2 Froth Floatation
It is a separation and harvest technique that involves segregation of algal cultures
from water. This is a method use since many years in the coal and mine cleaning
technology. It is based on materials differing in density. Air bubbles are usually
inserted within the device. Often a supplementary organic chemistry or change in pH
boosts the separation. It is achieved in a long column containing the solution for feed
which is ventilated below. A durable column of foam is produced from a side arm
close to the top of this column (Levin et al. 1962). It is an advanced technique which
can be too costly for commercial usage at this stage. The probability also exists of
merging with froth flotation and flocculation. If alum is added to algae as a
flocculant, for example, air is simmered over to isolate the flocculant by mass.
Also, it can unite with a compressor filter.
1.3.7.3 Dispersed Flotation
700–1500 μm bubbles formation takes place in dispersed flotation by mechanical
high-speed agitator coupled with air injection arrangement. Cationic N-cetyl-N-Ntrimetyl ammonium bromide (CTAB) and some other surfactants were used to
eliminate Scenedesmus quadricauda whereas non-ionic X-100 and anionic nature
SDS did not function (Chen et al. 2011).
Continuous-flow centrifuge is among the mostly utilized techniques. It is productive and collection of algae along with some other particles is the main motive of this
technique. However, it is used more frequently for the creation of algae-based valueadded products and usually not applied for generating fuel.
Besides to improve the shelf-life, moisture must be removed from the algae along
with separation techniques. Algae are extracted through a sequence of routes from
water including the separation phase.
1.3.7.4 Ozone Flotation
In one of the variants of the flotation, ozone bubbles are introduced into “disseminated flotation of ozone,” which were found to be effective in the Scenedesmus
obliquus harvest (Cheng et al. 2011). With this culture there was no conceivable
distinction along with traditional air flotation. Separation in ozone air-flotation was
1 Downstream Processing of Biofuels
23
raise the particles to the surface. The pressure applied produces bubbles which range
from 10 to 100 mm. Dispersed air flotation requires a higher pressure drop for
generating bubbles, and generates bubbles by continuously passing air through a
porous material. While less energy is consumed it is more costly (Moheimani et al.
2015).
1.3.7.2 Froth Floatation
It is a separation and harvest technique that involves segregation of algal cultures
from water. This is a method use since many years in the coal and mine cleaning
technology. It is based on materials differing in density. Air bubbles are usually
inserted within the device. Often a supplementary organic chemistry or change in pH
boosts the separation. It is achieved in a long column containing the solution for feed
which is ventilated below. A durable column of foam is produced from a side arm
close to the top of this column (Levin et al. 1962). It is an advanced technique which
can be too costly for commercial usage at this stage. The probability also exists of
merging with froth flotation and flocculation. If alum is added to algae as a
flocculant, for example, air is simmered over to isolate the flocculant by mass.
Also, it can unite with a compressor filter.
1.3.7.3 Dispersed Flotation
700–1500 μm bubbles formation takes place in dispersed flotation by mechanical
high-speed agitator coupled with air injection arrangement. Cationic N-cetyl-N-Ntrimetyl ammonium bromide (CTAB) and some other surfactants were used to
eliminate Scenedesmus quadricauda whereas non-ionic X-100 and anionic nature
SDS did not function (Chen et al. 2011).
Continuous-flow centrifuge is among the mostly utilized techniques. It is productive and collection of algae along with some other particles is the main motive of this
technique. However, it is used more frequently for the creation of algae-based valueadded products and usually not applied for generating fuel.
Besides to improve the shelf-life, moisture must be removed from the algae along
with separation techniques. Algae are extracted through a sequence of routes from
water including the separation phase.
1.3.7.4 Ozone Flotation
In one of the variants of the flotation, ozone bubbles are introduced into “disseminated flotation of ozone,” which were found to be effective in the Scenedesmus
obliquus harvest (Cheng et al. 2011). With this culture there was no conceivable
distinction along with traditional air flotation. Separation in ozone air-flotation was
1 Downstream Processing of Biofuels
23