Page 91 - Energy from Toxic Organic Waste for Heat and Power Generation

Toxic Waste From Biodiesel Production Industries and Its Utilization 77

form a by-product of biodiesel production, which is then sold to a glycerin
refiner [15]. The uncleaned wastewater can likewise be utilized for farm
cultivation, as long as it does not contain methanol. Small-scale producers
frequently send their wastewater to a municipal sewage treatment plant and
pay for this disposal.
6.3.2 Ion Exchange Resins

Biodiesel is sometimes cleaned utilizing a waterless technique. One tech-
nique includes utilizing ion exchange resins-styrene plastic beads which ex-
pel contaminants from biodiesel. This technique brings about significantly
less waste—just 1 pound of beads for every 900 gal of biodiesel produced
[16]. In principle, ion exchange resin beads can be reused, but nobody is
ready to reuse them because the cost of reusing is about the same as that of
purchasing new beads.
6.3.3 Magnesium Silicate (Magnesol)

Magnesium silicate is a mineral that can be utilized to clean biodiesel in
a waterless procedure. One normal brand name for synthetic magnesium
silicate is Magnesol. Likewise with ion exchange resins, less quantity waste is
produced—equivalent to about 1% of the weight of the biodiesel. Once uti-
lized, this mineral is not reusable in the biodiesel cleaning process. Generally
used minerals are disposed in a landfill [16]. Because this mineral is not
poisonous and the contaminants it has accumulated from the biodiesel have
nutritional value for animals, the waste magnesium silicate could theoreti-
cally be added to animal feed.

6.3.4 Used Oil Sediment
Once in a while, biodiesel is produced from waste cooking oil. This oil
contains solids, for example, meat and bone fragments or breading that must
be removed from the oil before preparing into biodiesel. The solids that
are removed from the waste cooking oil can be sold as animal feed. A few
biodiesel producers run the sludge from the strained oil through their oil
extraction press along with other products from their rendering process.

6.3.5 Glycerin
Biodiesel production will generate about 10% glycerol as the main
by-product [15]. The chemical compositions of adulterated glycerol for
different types of feedstock are listed in Table 6.3. In its adulterated form,