Disposal of heat from wastewater power plants using long channels (wastewater pit) is one of the ways that can
be used to achieve the requirements for the standard quality of wastewater. The purpose of this study was to determine the
characteristics of fluid flow in the wastewater pit of the power plant system which is equipped with water wheels with fins. The other aims of the study are to determine the fins effect on the performance of the water wheel applied to the wastewater pit and to find out the difference in temperature reduction of wastewater in a wastewater pit with and without a water wheel. The method of the research is composed of experimental methods and numerical methods. An experimental study was carried out by taking data on a prototype wastewater pit. While the numerical method is performed using t he Comput at ional Fluid Dynamics (CFD) method with the Ansys Fluent 2020 R1 software. Based on the research results obtained a water wheel has a positive effect in reducing wastewater temperature compared to a channel that is not equipped with a water wheel. The two fins transverse Parallel water wheel shows the highest improvement of reducing wastewater temperature around 5.564%. The difference temperature drop that can be generated between two-fins transverse parallel water wheel and without water wheel is 2.422⁰C. The computational results obtained from the present studies are in good agreement with the experimental data for the case of a wastewater pit without a water wheel.