At a sewage treatment plant, chelates (ferrous sulfate hydrate solution) are added after the sludge is incinerated to prevent the elution of heavy metals contained in the ash.
A plunger pump was used, which posed the following problems.

• The piping vibrated due to the pump pulsation, leading to looseness and leakage.
• When the chemical tank became empty, the pump would dry-run, which sometimes led to malfunctions.

The pump was replaced with a Smoothflow Pump.
Also, a float switch was installed in the chemical tank to generate an alert when a low amount of liquid is left.

• Smoothflow Pumps have no pulsation, so the piping no longer vibrates.
• Low liquid levels in the chemical tank are no longer missed.
• Because Smoothflow Pumps use a diaphragm method and have no rotating or sliding parts in their liquid end parts, there is no need to worry about malfunctions even in the rare case that dry-running occurs.
• The chemical can be injected evenly, which stabilizes the concentration.