The cellulose hydrazone derivative is a novel product prepared from dialdehyde cellulose with 2-hydrazino3,5,6,7tetrahydrocyclopentanethieno[2,3-d]-pyrimidin-4(4H)-on e under suitably selected conditions. It was found that the reaction of dialdehyde cellulose with the 2-hydrazino derivative decreased progressively in the series cellulose powder, viscose wood pulp and cotton linter. The principal objective of this research was to evaluate the effectiveness of dialdehyde cellulose hydrazone derivatives on sewage wastewater settling, percentage of total suspended solids (TSS), carbon oxygen demand (COD), and iron and chromium removal. About 30-50% of chlorine was removed after treatment using dialdehyde cellulose hydrazone derivatives, thus indicating their good efficiency for halogen removal. Cellulose hydrazone derivatives were recommended as good coagulants and removed Fe and Cr by 73.9% and 66.7%, respectively. Jar tests revealed that the wastewater was best treated with the addition of chemical coagulants such as FeCl3 or Al-2(SO4)(3) combined with cellulose hydrazone derivatives at optimum doses. The optimum conditions produced better cleaning-up and improved removal of COD and TSS up to 77% and 97%, respectively.