Removal of high iron concentration in water for microelectronics.
A microelectronics manufacturer in northern Ohio was suffering from poor iron removal from its well water. The plants softening equipment was made up of a multi-step oxidizing process which would precipitate iron prior to softening the water. Incidentally, the precipitated iron would form into a red iron which frequently caused a blockage in the systems filter. Additionally, the build-up of red iron ruptured the filter, releasing iron into the softener, resulting in staining and fouling of the system. Due to this high maintenance, complicated system, more frequent regenerations and system maintenances were warranted and the plant was tasked with the need to hire three new personnel to maintain the system on a daily basis.
In 2015, a consultant was hired to evaluate the plant and recommend solutions to reduce the high concentration of iron. The consultant suggested using a packed bed counter flow of Purolite’s Shallow Shell Technology SSTC60 resin, efficient in regeneration and iron removal while supporting a low rinse volume, to address water hardness and iron concentration. Six vessels with 4cf each of the SSTC60 resin were regenerated with 10lb/cf of salt in an up flow, allowing the iron to be pushed back out of the vessel.
The SSTC60 packed bed counter flow eliminated leakage from the plant’s system, providing a continuous supply of softer water. This allowed for the elimination of the oxidizing step and solid waste disposal. The plant was also able to eliminate the extra labor and instead hire a part-time contractor to monitor the system. Salt use was reduced by 75% and cleaning was reduced by over 90%. The plant made use of a simple, minimal contracted maintenance system.
A total of 24cf SSTC60 resin was used at the microelectronics manufacturing plant. The resin continues to operate as designed and has not required any cleaning thanks to its estimated life expectancy of Purolite’s SSTC60 resin is 8-10 years.