Biodiesel is typically defined as the alkyl ester of a fatty acid. Biodiesel is produced by the trans-esterification of lipid feed stocks that are extracted from plant or animal sources. Unfortunately, the future of this fuel based on its current status appears to provide limited impact to truly reducing foreign oil dependency because of high cost (approximately 190Rs. Per gallon) and relatively low US production capability (if all of the existing oleo-chemical capability within the US is utilized only 500 million gallons of biodiesel could be produced per year; yet, the US burned over 60 billion gallons of petroleum-based biodiesel last year).
Lipid feedstocks represent over 75% of biodiesel production costs. This project focused significant efforts on developing potential lipid feedstocks for the production of biodiesel using sewage sludge. Additionally, several other methods are also discussed for the extraction of lipid from other alternate sources for the production of biodiesel.
As a means of further enhancing the market appeal of biodiesel, several techniques to improve environmental performance were evaluated including reducing oxide emissions and utilization of more environmentally friendly process chemical reagents.
The US Congress during the 2005 session passed a biodiesel tax incentive (a blender’s credit) which amounted to 47.00Rs per gallon blended if the lipid derived from most major oilseeds grown within the US or animal-based lipids (the law provides a list of all involved lipid feedstocks eligible for the 47.00Rs per gallon).
All other lipid feedstocks receive 23.50 per gallon when blended. This tax incentive has sparked a dramatic growth in the biodiesel industry.
(MTF) in the USA produce (dry basis) of microbial sludge annually. This sludge is composed of a variety of organisms which consume organic matter in wastewater. The content of phospholipids in these cells has been estimated at 24% to 25% of dry mass [4,5]. Since phospholipids can be transesterified they could serve as a ready source of biodiesel. The sludge produced is currently viewed as a waste product and disposed of through landfills, the land application on farms, or incineration. Since the sludge is produced through an established, necessary process, there is no extra cost associated with raising the microorganisms.