Organic waste is both an escalating environmental burden and an underutilized renewable-energy resource, especially in arid, rapidly urbanizing contexts such as Oman. This study evaluates how biodigester performance can be improved through feedstock selection and pre-treatment to increase biogas yield and overall viability. A mixed-methods approach combined laboratory-scale biodigester experiments with simulated scenarios. Five feedstocks (food waste, agricultural residues, livestock manure, mixed organic waste, and food-and-crop waste) and three pre-treatment methods (mechanical, thermal, and chemical) were assessed. Process variables, including pH, temperature, volatile solids reduction, and chemical oxygen demand, were monitored, and regression modeling with ANOVA quantified their influence on biogas yield. Thermal pre-treatment delivered the most substantial gains, increasing biogas yield by 25–30% and raising methane content to ~65%, outperforming mechanical and chemical options. Food waste and food-and-crop waste achieved the highest daily outputs (>58 L/day), while co-digestion enhanced microbial activity and digestion stability. Biodigester deployment can reduce greenhouse gas emissions by up to 70% and divert up to 90% of organic waste from landfills. High-yield systems show payback periods of ~2–2.5 years and net returns exceeding 30%. Statistical results confirm pre-treatment choice and pH as significant predictors of biogas output. During monitoring, reactors operated near 35°C and pH 6.8–7.2, achieving ~35% reduction in volatile solids and a COD of ~27,500 mg/L. Digestate contained ~2.5% N, ~1.2% P, and ~1.8% K for agricultural use. The regression explained 82% of the variance (R² = 0.82). Overall, the findings support optimized biodigester systems as scalable waste-to-energy solutions.