Feasibility of Recycling Residual Solid from Hydrothermal
Treatment of Excess Sludge |
Kyoungrean Kim1†, Koichi Fujie2, and Toshiharu Fujisawa3 |
1Marine Environment Research Department, Korea Ocean Research and Development Institute, Ansan P.O. Box 29, 425-600, KOREA 2Department of Ecological Engineering, Toyohashi University of Technology, Hibarigaoka 1-1, Tempaku-cho, Toyohashi, Aichi 441-8580, JAPAN 3EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, JAPAN |
Corresponding Author:
Kyoungrean Kim ,Tel: +82-31-400-6185, Fax: +82-31-408-4493, Email: kyoungrean@kordi.re.kr |
Received: June 15, 2007; Accepted: December 16, 2007. |
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ABSTRACT |
Residual solid in excess sludge treated by hydrothermal reaction was investigated as raw material for its recycling. Treated excess sludge and
residual solid were also focused on their content change during hydrothermal reaction. Two kinds of excess sludge, obtained from a local food
factory and a municipal wastewater treatment process, were tested under various conditions. Following hydrothermal reaction, depending on the
reaction conditions, biodegradable substrates in treated excess sludge appeared to increase. The separated residual solid was a composite composed
of organic and inorganic materials. The proportion of carbon varied from 34.0 to 41.6% depending on reaction conditions. Although 1.89% of
hazardous materials were detected, SiO2 (Quartz) was a predominant constituent of the residual solid. X-ray diffraction (XRD) experiments revealed
that the residual solid was of a partially amorphous state, suggesting that the residual solids could be easily converted to stable and non harmful
substances through a stabilization process. Thus, this technology could be successfully used to control excess sludge and its reuse. |
Keywords:
Biodegradability improvement | Excess sludge | Hydrothermal reaction | Residual solid | Resource recovery |
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