A municipal wastewater treatment plant needed a replacement pump for ferric chloride service. Their first instinct was the sensible one: source a standard replacement, match the flange and the motor, get the plant back online.
In ferric chloride service, that instinct produces a repeat failure.
The Problem
Ferric chloride (FeCl₃) is one of the most common chemicals in wastewater treatment — used for phosphorus removal and odor control — and one of the most aggressive on ordinary pump materials. A standard cast-iron or general-purpose dewatering pump installed in continuous FeCl₃ service begins degrading almost immediately: corroded housing, attacked seals, contamination of the process fluid, and unplanned outages at a plant that cannot afford them.
The existing motor gave a starting point — horsepower, RPM, mounting configuration. The wetted materials, the parts that actually touch the chemical, needed a complete reassessment.
The Technical Challenge
The question was never "which pump fits the flange." It was "which materials survive this chemistry, at this concentration, at this temperature and duty cycle, while meeting the hydraulic requirement."
Cast iron, carbon steel and standard elastomers are all attacked by ferric chloride. The failure is not dramatic — it is a slow loss of wall thickness, a hardening and cracking seal, a shaft that starts to pit. By the time it shows up as a leak, the decision was made months earlier at the selection stage.
How RBC Industrial Solved It
- Chemical assessment first. Reviewed FeCl₃ compatibility across the full fluid path before looking at models.
- Existing motor review. Confirmed mounting, power and RPM constraints so the hydraulic match held.
- Installation style evaluation. Vertical chemical pumps for sump and tank mounting with a submerged intake; self-priming chemical transfer pumps for above-grade installations with suction lift. The right answer depends on where the liquid sits, not on what is in stock.
- Wetted material selection. CPVC for good chemical resistance across a useful temperature range; PVDF where the service is more aggressive; EPDM seals, which are compatible with ferric chloride where many standard elastomers are not.
The Result
- A pump recommendation built for the actual chemical environment instead of a generic replacement.
- Chemical compatibility, installation style, motor specifications, mounting and duty cycle all verified together.
- No inherited failure mode — the plant did not buy a second copy of the same mistake.
- Higher upfront cost, materially lower lifecycle cost: repeated rebuilds and emergency callouts are the expensive option, not the cheap one.
A standard-replacement mindset in chemical service produces a predictable three-year cycle of rebuild, replace, rebuild. Selecting for compatibility first breaks the cycle.
Where RBC Industrial Fits
RBC Industrial supports municipal water and wastewater accounts with chemical pump selection, corrosion-resistant alloys and thermoplastics — including Monel 400 tubing and fittings for aggressive service — plus the compatibility review that happens before a PO. Send the chemical, concentration, temperature and duty; we will tell you what the wetted path should be.
RBC Industrial · (915) 845-8188 · www.rbc-industrial.com