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Co-biodrying of sewage sludge and organic fraction of municipal solid waste: A thermogravimetric assessment of the blends

Zhang, Difang, Luo, Wenhai, Liu, Yifei, Yuan, Jing, Li, Guoxue
Waste management 2019 v.95 pp. 652-660
burning, combustion, corn stover, mixing, municipal solid waste, raw materials, sewage sludge, temperature, thermogravimetry, waste management
This study investigated the thermogravimetric properties of sewage sludge and organic fraction of municipal solid waste (OFMSW) during their co-biodrying at different fractions. Sewage sludge and OFMSW were co-biodried at the mass proportion of 0%, 42.5% and 85% (of the total wet weight), respectively, with 15% cornstalk as the bulking agent. Results show that of these three raw materials, OFMSW exhibited the lowest ignition temperature and the highest burnout temperature. Moreover, OFMSW had a better comprehensive combustion performance (S) than sewage sludge. Blending OFMSW, sewage sludge and cornstalk showed the highest S value (4.0 × 10−7%2 min−2 °C−3). In addition, there existed certain interactions between the co-combustion process, especially at high temperature stage. The burning characteristics, including ignition performance, burnout efficiency, DTGmax and S increased with fluctuations in the first 6–9 days of co-biodrying process, and then declined in all treatments. Hence, 15-day of biodrying made the product with poor burning behavior (S value of 1.0 × 10−7–1.4 × 10−7%2 min−2 °C−3). More importantly, the optimal combustion performance was observed when co-biodrying the same amount (42.5%) of sewage sludge and OFMSW with the peak of 8.3 × 10−7%2 min−2 °C−3 achieved on day 9. In addition, the blends were easier to burn after the biodrying process.