EMERGING DEVELOPMENTS OF OPTIMIZATION OF ANAEROBIC DIGESTION PERFORMANCE USING RESPONSE SURFACE METHODOLOGY AND CENTRAL COMPOSITE DESIGN

The study evaluated the conversion of agricultural waste into renewable bioenergy through anaerobic digestion with emphasis on optimization of operating parameters. Agricultural residues including rice husk, sugarcane bagasse, corn stalks, vegetable waste, and cattle manure were considered for their physicochemical characteristics and digestion performance. Response Surface Methodology (RSM) combined with Central Composite Design (CCD) was used to optimize temperature, hydraulic retention time, and organic loading rate. Before optimization, methane purity was 58%; after optimization, methane concentration increased to 72%. The optimized conditions were a temperature of 37C, retention time of 25 days, and organic loading rate of 2.5 kg VS/m3/day. Under mesophilic conditions, peak gas production was observed around Day 20, with cumulative biogas yield of approximately 140-150 m3. The results demonstrate that parameter optimization improved methane quality and overall anaerobic digestion performance.