EFFECT OF SEEDING ON THERMOPHILIC COMPOSTING OF TOFU REFUSE

Disposal of tofu processing residue is recently a serious problem in Japan. In this research, accelerated methods of composting tofu refuse were explored. The effect of seeding on the composting reaction rate of tofu refuse was examined by measuring changes in CO2 evolution, temperature, conversion of carbon, and microbial succession. The timing of CO2 evolution and microbial succession differed substantially when sterilized tofu refuse was seeded with two different inoculum sources. This difference was restricted only to early composting stages and the total amounts of CO2 evolved from both composts were similar in the later stage of refuse degradation. The analysis of microbial succession indicated that the types of microorganisms primarily responsible for composting of the refuse were the same in the later stages of both experiments. In contrast to the composting of sterilized tofu refuse, no measurable effect of seeding was observed when air-dried tofu refuse was composted. Large numbers of microorganisms responsible for composting inhabited the air-dried tofu refuse. Although the succession of thermophiles and patterns of CO2 evolution were different in composting sterilized and dried tofu refuses, no clear difference was observed in the final conversion of C of the raw refuse in all treatments.