Quality improvement of mixed MSW drying using a pilot-scale solar greenhouse biodrying system

Abstract

This paper addresses on improving the drying performance of high-moisture content (57.76%) municipal solid waste (MSW) using novel-design solar greenhouse biodrying (SGB) reactors under various operating conditions. Approximately, 4000 kg of MSW was loaded into 3 reactors with passive and active aeration to investigate the pilot-scale system’s performance. We found that the pilot-scale reactor using passive aeration SGB, with a final moisture content of 30.51 ± 19.70%, does not meet requirements for cement production companies, although the system can maintain both the air temperature in the greenhouse and the highest energy-content gain in this study (6134.75 ± 245.30 kcal/kg). The active aeration method using 1.96 m3/kgMSW/day presented the highest performances for water removal, reducing water content from 57.76 ± 10.41% to 16.58 ± 10.88%, while the 0.78 m3/kgMSW/day method showed a final moisture content of 21.26 ± 12.60. Both conditions can raise the heating value above the user standard of 4500 kcal/kg. Nevertheless, the 1.96 m3/kgMSW/day method loses more carbon mass and yields a lower energy content than the other active aeration. We found that, with the pilot scale, an aeration rate of 0.78 m3/kgMSW/day showed good performance due to the high moisture content loss with and above the standard heating value. This condition can be implemented on a commercial scale.