Int. J. Hum. Capital Urban Manage., 5(4): 277-290, Autumn 2020 *Corresponding Author: Email: zeinabamin13@gmail.com Phone: +90-5050572263 Fax: +90-224 2942118 Internatonal Journal of Human Capital in Urban Management (IJHCUM) Homepage: htp://www.ijhcum.net/ ORIGINAL RESEARCH PAPER Improvements to increase the efciency of solar dryers for diferent waste sludge management Z. Amin*, N.K. Salihoglu Department of Environmental Engineering, Faculty of Engineering, Uludag University, 16059, Bursa, Turkey BACKGROUND AND OBJECTIVES: In this study, an integrated phase change material drying system was designed to evaluate the efciency of the system with the use of renewable solar energy for diferent types of sludge with diferent moisture content. METHODS: This study was performed on the wastewater treatment plant sludge, paint, and marble sludge. By distributng the screws on the sludge tray, covering the system foor with a black trash bag, and mountng the refector around the absorber tubes has increased the efciency of the system. FINDINGS: All the types of equipment used in the constructon of the system are used as heat storage material and increase the internal air temperature, and the sludge temperature of the system. Temperature is transferred sequentally through air and objects. This research was conducted in winter by 1156 Wh/m 2 mean internal cumulatve solar radiaton. Due to the reducton of solar radiaton, as the system was upgraded, more water was released from the sludge surfaces. By Scanning Electron Microscopy imaging, the porous surface was observed afer sludge drying. CONCLUSION: In this study, the waste sludge moisture decreased from 80% to 52.2% during three improvement stages. The paint sludge moisture content reduced from 56% to 25%, and marble sludge moisture in the fnal stage reached from 26% to 5.2%. The proposed solar dryer system is an economical way to reduce the sludge volume in the transportaton process. ©2020 IJHCUM. All rights reserved. ARTICLE INFO Artcle History: Received 27 May 2020 Revised 30 July 2020 Accepted 16 August 2020 Keywords: Absorber tubes Cumulatve solar radiaton Refector Renewable Solar Energy Scanning Electron Microscopy ABSTRACT DOI: 10.22034/IJHCUM.2020.04.01 NUMBER OF REFERENCES 39 NUMBER OF FIGURES 7 NUMBER OF TABLES 3 Note: Discussion period for this manuscript open untl January 1, 2020 on IJHCUM website at the “Show Artcle.