ENHANCED ANAEROBIC DIGESTION BY ADDING BIOCHAR AND SELENIUM OXIDE

Abstract

The continuous use of fossil fuels and the effect of greenhouse gases (GHGs) on the environment have initiated research efforts into producing alternative fuels from bioresources. To tackle GHGs emissions in the environment, biogas produced from solid waste and residues through anaerobic digestion (AD) presents a promising alternative to fossil fuels. Re- cent evaluations indicate that biogas offers significant advantages in both energy efficiency and environmental sustainability. Waste control and its management are crucial to the envi- ronment. While AD of FW is a sustainable method for producing biogas, it faces several chal- lenges that can limit its efficiency. In recent years, significant attention has been given to the AD of organic waste, with the use of additives to enhance biogas yield and process stability. This study investigates the synergistic effects of biochar and Se as additives. By incorporating these substances, the study aims to optimize the AD process and enhance the methane pro- duction rate. This research aligns with the global transition towards renewable energy sources and sustainable waste management. Low concentrations of Se added as sodium selenite (2.5 mg/L and 5 mg/L) boost bio- gas production, with 2.5 mg/L improving yields by 8% over the control. However, higher concentrations (10 mg/L) can inhibit the anaerobic digestion (AD) process. The combination of Se and biochar enhances AD performance, particularly when Se is deposited in smaller bi- ochar particles at 10 mg/L, yielding an 18% increase over control with biochar and a 75% in- crease over those without. Biochar mitigates the toxic effects of higher Se levels, fostering mi- crobial communities and promoting electron transfer. Overall, the synergy between Se and biochar can optimize biogas production enabling the use of higher Se concentrations effec- tively.