Analysis of the Extraction Capacity of Lipid Material from Landfill Leachate for Biofuel Production

Abstract

Landfill leachate, a pollutant with potential risks to groundwater, contains lipidic materials that can be recovered for biodiesel production. This study evaluated the efficiency of three pretreatment methods—thermal (200˚C and 250˚C), acidification (pH 2), and ultrasound (40 Hz for 120 min)—on lipid extraction from leachate samples collected in a landfill in southern Minas Gerais, Brazil. Lipid extraction was performed using a Soxhlet apparatus, and parameters relevant to biodiesel production were analyzed, including acidity, free fatty acid (FFA) content, and saponification index. Leachate characterization included pH, acidity, alkalinity, and oil and grease content (OGC). Thermal treatment at 250˚C resulted in the highest lipid yield (104.67 ± 5.04 mg·g − 1 ), followed closely by ultrasound (101.17 ± 0.59 mg·g − 1 ), indicating that both methods were effective, with thermal treatment slightly outperforming ultrasound in terms of yield. Despite a lower yield (55.7 ± 3.01 mg·g − 1 ), acidification was the most economically viable method due to lower energy demands. The extracted lipids contained approximately 98% FFA, indicating the necessity of acid-catalyzed pre-esterification prior to biodiesel synthesis. The study highlights the potential of transforming landfill leachate into a renewable energy resource through scalable and cost-effective processes.