2021 Volume 32 Pages 86-98
In recent years, the creation of a recycling-based society has become necessary. The aim of this study was to investigate relationships between the properties of construction sludge and humic substances contained in it. Significant correlations were confirmed between the ignition loss and pH of construction sludge and the content of humic acid. Moreover, significant correlations were observed between the pH and ignition loss of construction sludge, and between the pH and oxidation-reduction potential. This suggests that the values of ignition loss and pH are suitable parameters for estimating the content of humic acid in construction sludge. Through the application of a hydrothermal process to the construction sludge, fluvic acid was extracted selectively in measurements using a three dimensional-excitation and emission matrix. Analysis of the elemental composition showed there was a correlation between the construction sludge nitrogen content and humic acid.
