Table of Contents
ISRN Chemical Engineering
Volume 2013, Article ID 268947, 6 pages
Research Article

Recovery of Value-Added Products from Hydrothermal Carbonization of Sewage Sludge

Department of Mechanical Engineering, Faculty of Engineering, Chiang Mai University, Chiang Mai 50200, Thailand

Received 3 May 2013; Accepted 5 June 2013

Academic Editors: D. Cazorla-Amoros, A. S. Chiang, and A. Ragauskas

Copyright © 2013 Pannarai Saetea and Nakorn Tippayawong. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


This paper is about the conversion of wet waste stream into valuable products via thermal processing. Hydrothermal carbonization of sewage sludge was carried out at 200°C and 2.1 MPa in a closed reactor for 1–6 h. Main products were in solid and liquid phases. The resulting hydrochar was shown to have H/C and O/C ratios moving towards natural lignite, improved energetic content, and adsorption property in terms of iodine number. The aqueous solution was found to contain high concentration of plant food nutrients, especially nitrogen and potassium. They may be desirable for subsequent fuel and chemical production as well as applications in agriculture. The study shows that valuable products can be generated successfully from sewage sludge using hydrothermal carbonization.