Optimizing SCFAs Production from Tannery Sludge: Insights from Zeolite-Assisted Fermentation with Mild Thermal Pretreatment

Abstract

This study explores the potential of utilizing tannery sludge for short-chain fatty acids (SCFAs) production through fermentation, incorporating zeolites in the process. The study involved a mild thermal pretreatment of the sludge as well, aimed at enhancing the subsequent fermentation process by increasing the solubilization of the organic matter. Six thermophilic continuously stirred tank reactor runs with varying hydraulic retention times (HRT) and zeolite addition are conducted. Zeolites, known for their low cost and absorption properties, significantly impacted chromium concentrations. SCFA production levels remain relatively consistent across tests. However, the acidification efficiency, as reflected in the SCFAs/sCOD ratios, shows improvement in the presence of Chabazite. Specifically, the acidification efficiency is highest in test RB8 (0.92 COD/COD). This suggests that the addition of Chabazite enhances acidification efficiency in tannery sludge applications. The findings highlight zeolites' potential to absorb heavy metals and improve acidification efficiency, indicating promising practical applications for tannery sludge treatment.