Selecting a municipal wastewater-treatment technology requires more than comparing removal percentages because similar effluent quality can be achieved at substantially different energy and operational costs. This study developed a decision-oriented benchmark for three full-scale biological configurations—activated sludge, trickling filter, and natural lagooning—using 108 monthly plant records collected from January 2022 to December 2024 in north-central Morocco. Influent and effluent five-day biochemical oxygen demand, chemical oxygen demand, and total suspended solids were combined with treated volume and electricity use to calculate concentration-based and load-weighted removal, specific energy consumption, and electricity use per kilogram of five-day biochemical oxygen demand removed, while temporal variability was characterized from monthly and semester-level records. Activated sludge delivered the highest overall load-weighted removals (93.4%, 93.5%, and 93.9%, respectively) but required 0.651 kWh/m³. The trickling filter achieved 89.2%, 88.6%, and 92.4% removal at 0.319 kWh/m³ and 0.990 kWh per kilogram of five-day biochemical oxygen demand removed. Natural lagooning used only 0.018 kWh/m³ and removed 92.4% of five-day biochemical oxygen demand, but total suspended solids removal was lower and more variable (67.3%). Monthly specific energy consumption differed among configurations (Kruskal–Wallis H = 90.39, p < 0.001), and all Holm-adjusted pairwise comparisons were significant (p < 0.001). A qualitative Pareto interpretation identified activated sludge as the quality-priority option, natural lagooning as the electricity-minimization option, and the trickling filter as the most balanced solution under the studied conditions. The benchmark converts routine operational data into a transferable technology-selection framework for small and medium-sized communities in water-scarce and energy-constrained regions.