Positive Operations on Wastewater Sludge Drying: Comparison of Back-Mixing and Sawdust Addition

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• 作者：Jie Li ; Erwan Plougonven ; Laurent Fraikin ; Thierry Salmon ; Dominique Toye ; Emmanuel Nistajakis ; Angélique Léonard
• 刊名：Energy & Fuels
• 出版年：2016
• 出版时间：April 21, 2016
• 年：2016
• 卷：30
• 期：4
• 页码：3014-3019
• 全文大小：295K
• 年卷期：0
• ISSN：1520-5029

文摘

This work compares two positive operations, back-mixing and sawdust addition, on the drying of wastewater sludges. The influences of back-mixing (with mass percentages of dried sludge of 40, 60, and 70% on a dry basis) and sawdust addition (40% on a dry basis) operations on the drying rates of sludge in a pilot-scale fixed bed were studied. X-ray tomography was used to monitor the evolution of structural characteristics of the samples during drying. When using the same mass percentage of dried materials (40%), the sawdust–sludge mixture has a higher drying rate than the back-mixed sludge as a result of higher initial and final bed volumes together with higher total exchange surface areas. To reach a similar rate increase with a back-mixing operation, 60% dried sludge must be back-mixed.