At present, a cost-effective selection of parameters for Chemical Oxygen Demand (COD) and turbidity reduction is of great importance for wastewater treatment. Like most water treatment processes, the coagulation treatment process may sound simple but is considered as an important method for wastewater treatment as it helps to remove COD and other pollutants found in wastewater. Poly aluminum chloride (PAC) with Poly ammonia (PA) coagulants was used to study the performance of the coagulation process of sludge wastewater obtained after the dewatering process. A scanning Electron Microscope (SEM) machine was also used to compare the characteristic of the flocs produced after treatment. The influence of coagulant dosing and settling time characteristics of the flocs were examined. Based on the result, with the use of poly aluminum chloride, it shows a removal efficiency of 77.9% COD. Furthermore, with the addition of Poly ammonia (PA), a greater efficiency removal of 80.6% of COD was obtained with higher turbidity removal and better flocs cohesion. Results also indicate that varying other treatment parameters like pH and temperature for effective pre-treatment have little or no significant effect on COD as well as turbidity removal.