Which tool is recommended for measuring reject flow during the system operation?

The recommended tool for measuring reject flow during system operation is a graduated cylinder. This tool allows for precise measurement of liquid volumes, which is important when evaluating the performance of a water treatment system, particularly in processes like reverse osmosis where monitoring reject flow is critical.

A graduated cylinder provides a clear, direct measurement of the volume of water discarded (reject flow) over a specific period. This information can help technicians optimize system efficiency, as understanding the amount of reject flow informs maintenance and adjustment of the water treatment process.

Other tools like a water meter, pressure gauge, and flow sensor have their own functions and applications but are not as effective for accurately measuring small volumes of reject water in a controlled manner. A water meter generally measures total water usage rather than specific reject flows. A pressure gauge measures conditions within the system but does not give volume measurements. A flow sensor can provide flow rates but might not deliver the precision needed to measure reject flow volumes accurately in specific situations. Thus, the graduated cylinder is the most suitable choice for this particular task.