Effects of Earthworm Cast Addition on Food Waste Compost under Co-composting with Sawdust

Food waste has been recognized as a critical problem in Korea and many research was conducted to efficiently reutilize or treat food waste. Main purpose of this research was to evaluate a feasibility for producing fermented organic fertilizer with mixture of earthworm cast (EC). Four different treatments were mixed with food waste and EC at the rate of 0, 10, 20, and 30%, respectively. Total days of composting experiment were 84 days and each sub samples were collected at every 7 days from starting of composting. Results showed that inner temperature in composting was increased to 70 ± 4°C within 5~10 days depending on mixing ratio of EC. Among different treatment, the highest increase of inner temperature was observed in treatment mixed with food waste and EC 30%. After finishing composting experiment, maturity was evaluated with solvita and germination test. Maturity index (MI) of each treatment was ranged between 5~7 indicating that manufactured fertilizer was curing or finished stage. Calculated germination index (GI) was at the range of 104~116 depending on mixing ratio of EC. Both MI and GI showed that manufactured fertilizer was suitable for fertilizer criteria while control (FW only) was not adequate for composting. Overall, earthworm cast can be utilized for improving compost maturity by mixing with food waste and more research should be conducted to make high quality of food waste compost with earthworm cast in agricultural fields. Changes of temperature in compost piles during co-composting with earthworm cast.