As concerns rise over depletion of fossil fuels and their contributions
to global warming, biodiesel has grown in popularity and worldwide
production is increasing annually. The National Biodiesel Board reports
that the United States produced approximately 1.8 billion gallons of biodiesel
in 2013. Similarly, the European Union produced slightly more
than 1.8 billion gallons in each of the last several years. Other countries,
like Brazil, have implemented a mandate to include at least 7% by volume
biodiesel in all diesel fuels.While biodiesel offers a myriad of benefits,
its production engenders a big waste problem. The production of
glycerol generates approximately 10% by volume of a glycerol co product
(see Fig. 1). Consequently, this means that approximately 200
million gallons of biodiesel-waste glycerol was generated in 2013 in
the U.S. alone.