Bioresource Technology 2015-06-01

Process development for scum to biodiesel conversion.

Chong-hao Bi, Min Min, Yong Nie, Qing-long Xie, Qian Lu, Xiang-yuan Deng, Erik Anderson, Dong Li, Paul Chen, Roger Ruan

Index: Bioresour. Technol. 185 , 185-93, (2015)

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Abstract

A novel process was developed for converting scum, a waste material from wastewater treatment facilities, to biodiesel. Scum is an oily waste that was skimmed from the surface of primary and secondary settling tanks in wastewater treatment plants. Currently scum is treated either by anaerobic digestion or landfilling which raised several environmental issues. The newly developed process used a six-step method to convert scum to biodiesel, a higher value product. A combination of acid washing and acid catalyzed esterification was developed to remove soap and impurities while converting free fatty acids to methyl esters. A glycerol washing was used to facilitate the separation of biodiesel and glycerin after base catalyzed transesterification. As a result, 70% of dried and filtered scum was converted to biodiesel which is equivalent to about 134,000 gallon biodiesel per year for the Saint Paul waste water treatment plant in Minnesota. Copyright © 2015 Elsevier Ltd. All rights reserved.