Effects of the aeration pattern, aeration rate, and turning frequency on municipal solid waste biodrying performance

Interactive influences of the aeration pattern, aeration rate, and turning frequency on municipal solid waste biodrying performance were investigated. Energy and water mass balances were used to identify the main water-removal routes and determine the amount of energy used and efficiency. Changing the aeration pattern and turning frequency did not significantly affect biodrying performance when the other conditions and total aeration volume were constant. The total aeration volume controlled the pile temperature and evaporation, making it the main factor affecting water loss during biodrying. A continuous aeration rate of 0.5 L kg^-1 dry matter·min^-1 gave the best biodrying performance (the highest water-removal rate, biodrying index, and sorting efficiency, 0.5 kg kg^-1, 4.12, and 86.87%, respectively, and the highest lower heat value (LHV) and heat utilization rate, 9440 kJ kg^-1 and 68.3%, respectively). There was an optimum aeration rate, water loss reaching a maximum at an aeration rate of 0.5 L kg^-1 DM·min^-1 and not increasing further as the aeration rate increased further. Lower aeration rates gave higher volatile solid degradation rates. The effects of turning could be achieved by increasing the aeration rate. The recommended biodrying parameters are continuous aeration at an aeration rate of 0.5 L kg^-1 dry matter min^-1 and one turn every 3 d.