BIOGAS PRODUCTION FROM TOFU LIQUID WASTE ON TREATED AGRICULTURAL WASTES

The Tofu Liquid Waste (TLW) as a pollution might be processed into biogas which was environmentally friendly and had potential to replace burning wood or oil. However, the waste could not directly be employed as the biogas substrate due to the high nitrogen content which was not suitable to the methanogen microorganism on the biogas digester and did not produce biogas. It was therefore necessary to adapt the carbon-nitrogen ratio in TLW with the addition of other organic materials that had a lower nitrogen content so it would be a suitable substrate for generating biogas. The research was aimed to evaluate the addition of the other organic material on the TLW to increase the biogas production. The results showed that TLW combined with sheep dung, cabbage waste, bamboo leaves and paddy straw respectively produced biogas as much as 14,183, 7,250, 2,400, 895 cm³ in 20 days. The 4 treatments gave the same quality of biogas, which was determined using the water boiling test. The pH fluctuation during the process was in the right pH for anaerobic digestion, thus it was not the limiting factor.