As the global population continues to grow at an alarming pace, the generation of Human Waste (HW) has become a serious challenge to environmental and public health. Anaerobic Digestion (AD) offers a means to convert human waste into valuable biogas. However, optimizing the performance of anaerobic digesters, particularly concerning mixing efficiency, residence time measurement, and biogas production, remains complex. While the significance of mixing and residence time in anaerobic digesters is well-established, determining the most effective approach remains challenging. Computational Fluid Dynamics (CFD) modeling proves instrumental in addressing this challenge, providing insights into flow dynamics within the digester. A key parameter in this study is the Uniformity Index (UI), crucial for assessing mixing efficiency. In this study, with the help of CFD, the effect of various shapes of the biodigester and the configuration of baffles on the mixing efficiency of the biodigesters has been investigated. The UI index of the unbaffled rectangular cuboid with curved edges biodigester is the least. The highest UI is for a baffled rectangular with a curve-shaped biodigester. The mixing performance of an unbaffled cylindrical-shaped biodigester is the same as that of a baffled rectangular-shaped biodigester.