WAC Resin Chemical Dilution Skids

A water treatment systems integrator was delivering a water treatment system for an industrial end-user in Michigan that relied on weak acid cation (WAC) resin vessels for metals removal. Proper regeneration of the WAC resin required precise chemical dilution of hydrochloric acid (HCl) and sodium hydroxide (NaOH) before injection into the vessels. The integrator needed two matched dilution skids that could handle these aggressive chemistries, integrate tightly with integrator-supplied valves and instrumentation, and ship ready for field installation.

The skids had to combine chemically compatible piping materials, precise flow control, and a robust control architecture that would tie cleanly into the larger plant PLC. Factory acceptance testing, pressure testing, and loop checking were required prior to shipment so the skids could be installed with minimal onsite commissioning time.

Fliteway fabricated two painted carbon-steel dilution skids, each built around chemistry-specific piping: poly-lined carbon steel for the HCl dilution circuit and Schedule 80 316 stainless steel for the NaOH dilution circuit. Integrator-supplied components — eight automated flow control valves, two differential pressure transmitters, a conductivity transmitter and sensor, two flow meters, six pressure gauges, and four chemical metering pumps — were integrated into the Fliteway piping and skid structure.

Each skid carried its own VFD / remote I/O panel housed in a NEMA 4 painted steel enclosure. The panel included an Allen-Bradley Point I/O Ethernet adapter module, two Allen-Bradley VFDs, Hand/Off/Auto switches for the chemical metering pumps, and an Ethernet switch to tie back to the plant network. Fliteway ran conduit and wire from the VFD / remote I/O panel to every flow control valve and instrument on the skid.

Control panel bills of materials, layout drawings, and wiring details were issued as part of the submittal package. Before shipment, Fliteway performed full factory acceptance testing alongside the integrator — including pipe pressure testing, instrumentation loop checks, electric and manual valve operation checks, electrical system checks, HMI programming checks, and logic testing — and budgeted a week of onsite startup support for commissioning.

Both dilution skids were constructed, tested, and shipped as matched pairs ready for field installation on the end-user's WAC treatment system. The separation of HCl and NaOH piping materials eliminated chemical compatibility risk, and the pre-integrated VFD / remote I/O panels simplified tie-in to the overall plant control system.

Factory acceptance testing with the integrator ensured that instrumentation, valves, and PLC logic were verified before the skids left Cudahy, reducing onsite startup risk and shortening commissioning duration in Michigan.