Effect of Stillage Pretreatment During a Coupled Scoria-Supported Anaerobic Digestion Followed by Aerobic Degradation. Issue 14 (February 2021)

• Record Type: Journal Article
• Authors: Gebreeyessus, Getachew Dagnew; Mekonnen, Andualem; Chebude, Yonas; Asaithambi, Perumal; Sreekrishnan, Trichur Ramaswamy; Alemayehu, Esayas
• Is Part Of: Air, soil and water research. Volume 2021:Issue 14(2021)
• Publication Date: 2021-02
• Subjects: Chemical oxygen demand -- organic loading rate -- pretreatment -- scoria -- stillage; Air quality -- Research -- Periodicals; Soil science -- Periodicals; Water quality -- Research -- Periodicals; Conservation of natural resources -- Research -- Periodicals; Conservation of natural resources -- Periodicals; Agricultural conservation -- Research -- Periodicals; 363.7
• DOI: 10.1177/1178622121991810
• Languages: English
• ISSNs: 1178-6221

Abstract

The objective of this study was to evaluate the treatment efficiency of a coupled stillage anaerobic digestion, which was performed in scoria-packed continuous reactors and following aerobic degradation. The optimum organic loading rate was determined for the continuous anaerobic digestion of a molasses ethanol distillery stillage with and without wet air feed pretreatment. The pretreatment of the molasses ethanol distillery stillage brought a significantly higher chemical oxygen demand removal in anaerobic digestion with an increased loading rate of 2000 mg/L d when compared with the raw stillage. The results also showed a complete removal of the biological oxygen demand following the coupling of anaerobic digestion with aerobic degradation. During the later stillage aerobic treatment, 68% of the chemical oxygen demand was removed within 8 hours of retention time. Despite the color, the removal of organics in stillage due to integrating wet air pretreatment, continuous anaerobic digestion, and aerobic degradation was successful. The pretreatment and hybrid technique also appears as a promising technique toward the sustainable management of stillage, thereby meeting discharge limit set for the ethanol industry by regulators.