Whole-plant electricity intensity is often available for wastewater treatment facilities, but its interpretation against nutrient quality is complicated by differences in plant scale, hydraulic loading, influent conditions, and treatment configuration. This study evaluated whether whole-plant specific electricity distinguished total phosphorus in treated effluent after accounting for those factors and for the phosphorus-treatment category documented in the annual French Urban Waste Water registry. Raw parameter-level self-monitoring measurements from January 2024 were reconstructed by exact plant code and date for the Seine-Normandie basin. The strict phosphorus set contained 655 plant-day occasions from 149 plants; one median per plant was analyzed by ordinary least squares with HC3 uncertainty. Relative to no entry in the annual registry phosphorus-treatment field, a standard documented entry was associated with an adjusted effluent-phosphorus ratio of 0.343, equivalent to 65.7% lower phosphorus (95% confidence interval: 39.4% to 80.5% lower; p<0.001). The advanced entry estimate was 43.0% lower but imprecise (95% confidence interval: 76.1% lower to 35.9% higher). A doubling of whole-plant specific electricity was associated with an estimated 8.0% lower effluent phosphorus, with an interval spanning 18.4% lower to 3.8% higher (p=0.177). The standard entry was also associated with a 0.238 higher apparent daily phosphorus-load reduction fraction (95% confidence interval: 0.122 to 0.354). In a contextual nitrogen analysis of 647 occasions from 142 plants, the electricity estimate was 1.0% lower (95% confidence interval: 9.5% lower to 8.2% higher), whereas documented denitrification was associated with 71.0% lower effluent nitrogen. The standard documented phosphorus-treatment entry showed a precise cross-plant association with January effluent phosphorus, while the whole-plant electricity estimate was smaller and imprecise. Comparisons of nutrient outcomes across heterogeneous plants therefore require explicit treatment-category, influent, hydraulic, and scale context.