Material and moisture balance in a full-scale bio-drying MBT system

抄録

Bio-drying MBT is a type of mechanical-biological treatment (MBT) system and moisture removal by an aerobic process is preceded to enhance separation efficiency of combustible fraction for fuel production. In this study, a full-scale biocell type bio-drying MBT system which implies material and air recirculation were investigated. Mass balance of each waste component was estimated through laboratory analyses of waste samples and waste tonnage data. During the separation of biodried outputs, about 60 % of fuel materials were recovered and the rest were transferred to the next reactor. Wood was decreased due to size reduction and its fine particles filled up the mixed fine component. This caused the changes in mass and biodegradability of mixed fine component as well as organic degradation. Moisture balance was simulated by using operation data. The bio-drying process was subjected to four consecutive phases by controlling the airflow rate and the mixing ratio of fresh air and recirculating air according to the waste temperature. Half of the water removal occurred at stabilization phase, the longest period. Rest water removal occurred for only 6 days in total and this was promoted by either high waste temperature or high airflow rate.