The Effectiveness of Biogas Method from Rice Husks Waste: Liquid Anaerobic Digestion and Solid-State Anaerobic Digestion

Abstract

Liquid Anaerobic digestion (L-AD) generally was operated in the total solid between 0 until 15%, while the Solid- State Anaerobic Digestion (SS-AD) operated at total solid higher than 15%. In this research, waste of rice husk were evaluated to determine the effect of biogas production of Liquid Anaerobic Digestion (L-AD) and Solid-State Anaerobic Digestion (SS-AD). This experiment was operated in batch system in the laboratory scale of anaerobic digestions and at room temperature, with C/N ratio was set at 25oC. Total solids (TS) was varied from 5, 7, 9, 19, 21 and 23%. Pretreatment of rice husk was needed to lower the high lignin content in the material, with added sodium hydroxide (NaOH). Biogas produced was measured by using the method of water transfer every two days for 60 days. The results showed the chemical pretreatment of sodium hydroxide increase the production of biogas, with the highest yield biogas difference between LAD condition and SS-AD by 14%. The highest yield biogas production in rice husk was obtained at TS 19%, with a productivity volume of 935.5 ml. Specific biogas production in TS 5, 7, 9, 19, 21 and 23% was 57; 56.64; 45.36; 24.62; 15.15; and 12.45 ml/g TS. The concentration of total solid to L-AD higher than SS-AD conditions. Further research needs to be studied is to optimize the yield of biogas with SS-AD system.