Palm Oil Mill Effluent (POME) Treatment—Current Technologies, Biogas Capture and Challenges

Abstract

Palm pressed fibre (PPF) is a by-product from palm oil milling process. There are approximately 5-7% of residual oils retained in PPF after the oil extraction process. Hexane is commonly used as solvent for extraction of the residual oil due to its low cost and high oil solubility. However, the high boiling point of hexane leads to degradation of carotenes during oil recovery. Besides, hexane is highly flammable and causes air pollution through fugitive emissions. Thus, there is interest in identifying alternative solvents to extract residual oil from PPF. In this chapter, a new approach that combines Computer-Aided Molecular Design (CAMD) and Analytic Hierarchy Process (AHP) is presented. The proposed approach can determine the alternative solvents that exert favourable attributes for oil extraction. Both physical and environmental properties are chosen as design criteria to generate solvents with improved performance and environmental characteristics. Nonetheless, it is difficult to evaluate the relative importance of each property since properties that belong to different categories cannot be compared on a common scale. This issue needs to be addressed seriously as different relative weights will identify different solvents. The main attraction of this AHP-CAMD approach is that the relative importance weight of those identified properties can be systematically defined. AHP structures the CAMD problem in a hierarchical manner that allows physical and environmental properties to be compared under the same analysis. Through this approach, the identified alternative solvents have comparable or better performance as compared to hexane.