Exploring Liquefied Dimethyl Ether for Lipid Extraction from Fat Balls in Wastewater Pumping Stations

Fat balls are floating solid substances formed by fat, oil, and grease (FOG) that are discharged into wastewater systems. This material has a high proportion of organic and calorific content, which could serve as an alternative lipid feedstock for biodiesel production. This study aimed to characterize and evaluate an effective method for recovering lipids from fat balls by using liquefied DME (L-DME). The lipid extraction performance of L-DME was compared with that of mechanical shaking extraction using hexane. Fat balls consisted of 55% of the total solid content, with 52% of raw lipids (based on hexane extraction). The results showed that the L-DME method extracted 46% of the lipids, with a recovery efficiency of approximately 89% of the total lipid content. The characteristics of methyl esters showed that the unsaturated fatty acids and saturated fatty acids represent 52.3% and 47.8% of total methyl ester produced, respectively. The results demonstrate the great potential of utilizing the L-DME technique to extract lipids from fat balls.