Use of Waste Sludge from the Tannery Industry

In this study, the conversion of waste sludge from a tannery industry into useful materials was the aim. For this purpose, the thermal behavior of waste sludge was investigated using thermogravimetry (TG) and a vertical fixed-bed reactor. Thermogravimetric analysis was performed at different heating rates to the temperature of 750 degrees C. The main pyrolytic decomposition step was observed in the temperature range of 248-500 degrees C. In the fixed-bed reactor, waste sludge was pyrolyzed at 450 and 600 degrees C in a nitrogen atmosphere. Pyrolysis products were separated as gas, liquid, and char. The temperature was found to be slightly effective on the product distribution. Pyrolysis gas had a considerable gross calorific value (23.22 MJ N m(-3)). Although the pyrolylic oils had reasonable calorific value, they contained a high amount of nitrogenated and oxygenated compounds. Using waste sludge as a raw material for activated carbon production was also investigated. For this purpose, activated carbons were produced from waste sludge by physical and chemical activation methods. To check the potential of activated carbons to be used as adsorbents, methylene blue, phenol, and Cr(VI) adsorption studies were carried out with selected activated carbons.