Biogas production from tofu liquid waste with effective microorganisms biocatalyst in anaerobic digester

The energy crisis is a challenge to develop alternative energy sources to sustain the energy availability now and in the future. An alternative energy source that can be used and easily developed is biogas. The liquid tofu waste from Somber Small Industrial Center (SSIC) Balikpapan was applied as alternative energy to replace fossil energy that can be developed in local society. This research aims to find the characteristic of biogas produced and the potential of liquid tofu waste to produce biogas. To obtain biogas, all raw materials (tofu liquid waste and biocatalyst) were added into the fixed-dome digester tank using a 25 Liters plastic jerry can and fermented for 35 days. The composition effect of tofu liquid waste and Biocatalyst Effective Microorganisms 4 (EM-4) were investigated. The result showed that the optimum digester temperature conditions were 25 – 30 °C while pH after fermentation measured was 7.0. In a flame test, the biogas obtained from the fermentation process produces a bluish-color flame containing at least 45% methane gas. Somber Small Industrial Center (SSIC) has excellent potential in utilizing liquid tofu waste to biogas because it can produce 63.417 m³/day of biogas which is enough for cooking in a production house.