Biodrying of Organic Fraction of Municipal Solid Wastes

Abstract

The effect of air flow rate on the change of biomass (organic waste material) temperature and moisture content during an autothermal drying process is discussed. The laboratory-scale experiments were performed using a 240-dm³ horizontal composting reactor equipped with an air supply system, biomass temperature measuring system, and air humidity and temperature sensors. An organic fraction of municipal solid waste with the addition of a structural material was used as a substrate in this process. As a result of the autothermal biodrying process, the initial moisture content of organic waste ranging from 0.8 to 0.9 kg_H2O/kg of raw waste mass decreased by 50%. Water balances were calculated before and after biodrying, and the difference was less than 10%. The heat of combustion and the calorific value of dried wastes ranged respectively from 6,750 to 12,280 kJ/kg and from 8,050 to 10,980 kJ/kg. The biodrying efficiency varied from 0.73 to 0.97, depending on process conditions. Energy balances showed that average biological energy production rates varied between 1.66 and 6.90 W/kg of raw waste mass.

Keywords:

• Adiabatic composting reactor
• Biodrying
• Efficiency
• Municipal solid wastes
• Organic matter

ACKNOWLEDGMENTS

The work was supported by grant No. R14 017 01 founded by the Ministry of Science and Higher Education in Poland.