Flow Measurement in Wastewater Treatment: What Works and What Doesn't

Wastewater Is Not Clean Water

A flow meter that works perfectly on potable water will fail spectacularly in a wastewater treatment plant. The liquid contains suspended solids, rags, grease, grit, and dissolved chemicals that attack conventional materials. Mechanical meters seize. Ultrasonic meters lose signal in aerated flows. Differential pressure meters clog.

Electromagnetic: The Only Realistic Choice

An electromagnetic flow meter handles wastewater because the measurement principle doesn't care what's in the water, only that it conducts electricity. No obstructions to catch debris. No transducers to foul. No impulse lines to block.

Material Selection for Wastewater

Liner

• Hard rubber (ebonite): The workhorse for raw wastewater. Resists abrasion from grit, handles DN50–DN3000.
• Polyurethane: For activated sludge lines with high solids (5× the wear life of rubber).
• PTFE: Only for treated effluent or chemical dosing lines.

Electrodes

• 316L: Fine for municipal wastewater.
• Hastelloy C-276: Industrial wastewater with chlorides or acids.

Critical Features

• Empty-pipe detection: Prevents false readings during tank drainage or pump-down.
• Self-cleaning electrodes: Our electrode geometry minimises grease build-up.
• IP68 protection: Wastewater meter chambers flood regularly.

From inlet works to final effluent, we can configure the right meter for every measurement point in the plant.