What maintenance action should be performed regularly on pH probes?

• A. Re-calibrating every month
• B. Cleaning them before calibration
• C. Replacing them annually
• D. Checking temperature sensors

Answer: (B)

Regular maintenance of pH probes includes cleaning them before calibration. Over time, pH probes can accumulate contaminants like dirt, oil, or biological growth on the sensing surface, which can affect their accuracy and responsiveness. Cleaning the probes ensures that they provide reliable measurements when calibrated.

This is critical because accurate pH readings are essential for effective monitoring and treatment in wastewater processes. If the probe surface is not clean, the calibration may not reflect the actual pH levels present in the wastewater, leading to potential operational issues.

While options like re-calibrating every month, replacing them annually, and checking temperature sensors are important maintenance actions in a broader sense, they do not specifically address the immediate need to ensure a clean sensing surface for proper operation and reliable readings.