THE EFFECT OF CONCENTRATED SOLAR ENERGY ON DRYING OF TREATMENT SLUDGE
- 1. Konya Technical University, Faculty of Engineering and Natural Sciences, Department of Environmental Engineering, Konya, Turkey
- 2. Konya Technical University, Faculty of Engineering and Natural Sciences, Department of Environmental Engineering, Konya, Turkey
Abstract: Treatment sludge are concentrated wastes including organic or inorganic impurities and resulted from separation process of wastewater treatment plants. Although the sludge is separated by dewatering processes, it contains a large amount of water in its contents. The water content of the non-fluidized sludge cake from the centrifugal dewatering unit varies between 82% and 78% in the Konya wastewater treatment plant. This high-water content in the sludge is a problem that needs to be overcome in the implementation of final disposal or reuse alternatives. It is necessary to increase the solid matter content of the sludge in order to burn, landfilling or to use as fertiliser. Therefore, drying is a mandatory process for these reuse or disposal options. Thermal dryers operated by fossil fuel could be achieve high drying rates, but its cost is disadvantage. Greenhouse type indoor or outdoor drying plants, where the sludge is laid on the floor in a thin layer to benefit from solar energy, have relatively low cost but requires large areas. It is necessary to increase the number of drying options that use the highest level of solar energy. Concentrated solar energy systems are promising alternative to overcome these problems. Parabolic trough types solar collectors where the heat generated at high temperatures is used for industrial application such as production of electricity by steam power. In this study, a mechanism of direct sludge passing through the tube located at the focal point of the parabolic collector was installed to concentrate solar energy on the lower area. The moisture was removed by means of ventilation while the sludge was heated in the metal tube. It was observed that the solid matter content increased from 21% to 64% on a day where the average solar radiation is 1047 W/m2 and the sludge flow rate of 29 g/min.