Hydrolyzed cassava starch was a modified polymer from bio-flocculants. This modification aims to improve cassava starch performance as flocculants on tannery waste water treatment. In this research, cassava starch was mixed with calcium hydroxide and aluminium sulphate. The mixture was heated increasingly 0,5oC per minute until reaching 90 oC with constant speedat 100 rpm. When maximum viscosity is reached then sodium chloride is immediately added. After that, the product ability was tested in reducing turbidity, removing chromium (VI) and total suspended solid of tannery waste water. The study was done to compare the effect between flocculants and salt dose variation on flocculation processes. The test result shows that the percentage of turbidity reduction, chromium (VI) removal and TSS removal increases as the raising of flocculants dose. Flocculants dose of 10 ml gives turbidity reduction up to 95,77%, chromium(VI) removal to 82,5% and TSS removal to 99,28%. Salt dose of 110% gives best turbidity removal on the average of 84,13%, salt dose 65% gives best chromium(VI) removal on the average of 50,38% and salt dose of 80% give best TSS removal on the average of 93,83%. From this research, it can be concluded that hydrolyzed cassava starch flocculantsare potentially implemented in waste collecting vessels.
Keyword: Hydrolyzed Cassava Starch, bio-flocculants, waste water