2. Materials and methods
2.1. Site of investigation
The site of investigation was the food processing factory (Naoetsu-Yushi Co. Ltd. Japan) which has been
introduced the oil-water separation technology in wastewater treatment process. The technology was developed
based on specific gravity and flow rate control without chemical and biological treatment. The scheme of energy and
material balances is shown in Fig. 1. This factory produced boiled chicken from culled chicken and in the process of
boiling, wastewater was discharged with a high portion of organic oil. Oil-water separation technology recovered oil
from wastewater and reused as fuel and oil-removed wastewater was treated within the factory and reused as hot
water for melting snow.