This study investigated the effects of different leachate recirculation systems, viz. drainage blankets (DB), multiple horizontal trenches (HT), and combined system of horizontal trenches and vertical wells (HT-VW), on the slope stability of bioreactor landfills for heterogeneous anisotropic waste conditions. The validation of the numerical model was carried out, and the outcomes were compared with the existing literature. The maximum pore water pressure (PWP) was observed when multiple HT systems were used for leachate recirculation under different injection pressures. Therefore, injection through multiple HT results in a higher PWP, followed by HT-VW, with the least observed through DB systems. High-pressurized leachate injections of above 147 kPa were found to reduce stability of landfills. The leachate injection through the DB system resulted in a uniform distribution of moisture, even under low injection pressures, without affecting the slope stability. The HT-VW system achieved a degree of saturation of over 60%, wherein the vertical wells were installed between the horizontal trenches at a distance of 50 m. The factor of safety for the combined HT-VW system increased by 3–7% compared to HT systems alone, for various injection pressures. Based on the results, it was concluded that the combined HT-VW system is a cost-effective and efficient method for leachate recirculation in closed bioreactor landfills.