Sludge dewatering by pelletization/thickening system

ABSTRACT MS THESIS SLUDGE DEWATERING BY PELLETIZATION/THICKENING SYSTEM Hatice ERDEM Firat University Gratuate School of Natural and Applied Sciences Department of Environmental Engineering 2005, Page: 47 In this study, dewaterability of municipal wastewater sludge using a pelletization/thickening system that was recent developmented in order to eliminate problems associate with sludge dewatering and disposal has been investigated. In this system, ferric chloride and alum for conditioning and a polimer for dewatering was used. A laboratory-scale experimental equipment was utilized for dewatering. Dewatering efficiencies have been evaluated according to capillary suction time, specific resistance to filtration and filtration time. It was established that the water content of sludge passed from a pelletization/thickening system was 75.5% at 2.5 of pH while 94% at 7 of pH and that the lowest water content was reached at 2.5 of pH. In the conditioning stage of the system, first sludge was separately conditioned using ferric chloride and alum, and results of these experiments showed that ferric chloride was more effective than alum in sludge conditioning and provided a better dewaterability in comparison with alum. Then, the experiments was conducted by mixing at a specific ratios of this two coagulants, and it was found that the best conditioning was occured at mixing ratio of FeCİ3/alum=l/4. When obtained these findings were considered, it was established that using at mixing ratio of 1/4 of these coagulants provided a better dewatering efficiency than using a single coagulant (alum or ferric chloride). Finally, it was appeared that the dewatering performed using a pelletization/thickening system was as good as that of a conventional dewatering equipment,and even provided a better efficiency than that a conventional dewatering equipment due to the chemical type used. Keywords: Pelletization/thickening system, sludge, dewatering, conditioning, capillary suction time, specific resistance to filtration, filtration time IX