Biogas Production from Wastes of Tofu Industry with Effects of Water Hyacinth and Cow Manure Additions

Abstract

Biogas is one of the potential sources of energy to cope with the limitations of fossil energy. On the other hand, liquid waste of tofu industry, water hyacinth, and cow manure are poorly managed that can potentially pollute the environment. The type of those wastes was potential source for biogas production through anaerobic digestion due to high content of protein and nutrient. This study aims to determine the effect of addition of liquid waste of tofu industry (WT) and water hyacinth (WH) to cow manure (CM) on the biogas production. The amount of water hyacinth and cow manure were varied at 0-4 kg, while the liquid waste of tofu industry was fixed to 8 kg. The anaerobic digestion was conducted in biodigester container equipped with thermometer and biogas shelter. The biogas production was then analyzed using Gas chromatography–mass spectrometry (GC-MS). The optimum biogas was achieved at raw material ratio of 4:2:2 (WT:WH:CM) for 21 d. At this condition, 60 ppm of CH4 and 10,744 ppm of CO2 were obtained. Thus, the utilization of liquid waste of tofu industry, water hyacinth and cow manure as raw material of biogas production can minimize the environment problem and supply energy.