Which laboratory or field instrument is used to monitor the pH and temperature of wastewater?

• A. DO meter
• B. Flow meter
• C. pH/temp meter
• D. Microscope

Answer: (C)

Monitoring pH alongside temperature requires a pH/temp meter. This instrument is designed specifically to measure hydrogen ion activity (pH) and display the sample’s temperature, often with automatic temperature compensation to keep pH readings accurate across different temperatures. That combination is essential in wastewater work because pH readings can change with temperature, affecting process control and chemical dosing.

Other tools don’t fit this dual purpose: a DO meter measures dissolved oxygen, a flow meter tracks flow rate, and a microscope is for visual analysis of samples. So the pH/temp meter is the appropriate choice for watching both pH and temperature in wastewater.