Which of the following options does not pertain to the efficiency of filtration types?

The concept of filtration efficiency primarily relates to how effectively different types of filtration systems can remove contaminants from water. Factors such as filtration rate differences and general water treatment efficacy directly address how well a filtration method performs in purifying water or removing suspended solids, pathogens, and chemical pollutants.

The effectiveness of filtration in nutrient removal, while important in certain contexts, doesn't pertain to the primary efficiency measurements usually associated with filtration systems, which often focus more on physical and chemical contaminant removal rather than nutrients. Nutrient removal can be influenced by additional processes beyond standard filtration, such as biological treatment, which is not the focus of purely filtration efficiency discussions.

On the other hand, variations in operation costs affect the feasibility and practicality of different filtration options but do not directly relate to the effectiveness of the filtration process itself, making them relevant in operational assessments rather than efficiency metrics. Therefore, the choice that does not pertain to the efficiency of filtration types is the effectiveness in nutrient removal, as it diverges from the core evaluation of how well filtration systems accomplish their primary functions.