Which of the following is NOT a common method for measuring wastewater flow?

• A. Float, Electrical, Ultrasonic, Bubbler
• B. pH Measurement
• C. Temperature Measurement
• D. Turbidity Measurement

Answer: (B)

Flow is about how much liquid passes a point in a given time, so devices that relate to level or velocity are the ones you’d use to measure it. Float devices rise with the liquid surface and convert that height into a flow signal. Bubbler systems translate submerged depth into air pressure to determine depth and then flow. Ultrasonic meters send sound waves to the surface and calculate distance to determine level, which can be turned into flow data. Electrical meters, such as electromagnetic or other velocity-based meters, infer flow from the liquid’s motion.

pH, temperature, and turbidity, on the other hand, are measurements of water quality or process conditions, not the rate at which water is moving. pH specifically is a measure of acidity/alkalinity and doesn’t tell you anything about flow, making it the option that isn’t used for measuring wastewater flow.