Impact of biodiesel production on wastewater generation

Abstract

Biodiesel production has intensified in recent years and the traditionally applied method for its production is homogeneous alkaline transesterification, with the formation of esters and glycerol, which need to be separated. Also, the crude biodiesel needs to be purified at the end of the reaction to remove the remaining catalyst, glycerol, soap, oil, and alcohol, which can impair engine performance. This process generates large quantities of wastewater that need to be properly disposed of to avoid polluting the environment. This article provides a review of the biodiesel production process and the need for a purification step, focusing on wastewater generation. Traditional and advanced methods for treating wastewater originating from biodiesel production are described and discussed. Details regarding patents published in the past 5 years, related to techniques for the treatment of these wastewaters, are also included.