Abstract
The main objective of this study is to compare the performance of three alternative materials used to improve dewatering of sludge produced from secondary settling tank of Mosul medical city wastewater treatment plant, those materials are Kaolin, Limestone and Clay stone.Six dry weight percentages for each alternative are used (2, 4, 6, 8, 10, 12) % from dry weight of sludge. The specific resistance to filtration (SRF) was used as a criterion to compare the studied materials. Experimental results showed that SRF is 4.1×1012, 5.9×1012, 5.8×1012 m/kg when 8% additional dose were used for each of Kaolin, Limestone and Clay stone respectively, this study showed that the best alternative material studied is kaolin which achieve decreasing efficiency in SRF more than 70%.