Massachusetts Wastewater Practice Exam

A peristaltic pump is indeed classified as a type of positive displacement pump. This classification is primarily due to its operational mechanism, which involves the movement of fluid through a series of rollers that compress a flexible tube. As the rollers move, they push the fluid forward while simultaneously creating a vacuum behind them, which draws in more fluid. This process effectively displaces a fixed volume of fluid with each complete cycle or rotation. The nature of positive displacement pumps is that they transport a constant volume of fluid per cycle, regardless of the system pressure. This is a key characteristic shared by peristaltic pumps, making them suitable for applications where precise dosing or handling of viscous materials is required. This ability to maintain a consistent flow rate, even against varying resistances, is advantageous in many wastewater treatment processes. In contrast, other types of pumps, such as centrifugal pumps, function based on the kinetic energy of a rotating impeller and do not operate on the same principle of displacing fixed volumes of fluid. Thus, the statement identifying peristaltic pumps as positive displacement is accurate and reflects their unique design and function within the context of fluid management systems in wastewater treatment.