How does industrial water softeners work?
Incoming water enters the water softener vessel, which contains the resin bed. The water's velocity slows as it spreads across the bed's larger surface area and travels through millions of tiny beads. Minerals in the water are drawn to the resin surface areas during this process. The water then exits the resin bed, free of the mineral-laden minerals, with only a minor drop in hydraulic head pressure. The hardness minerals in the water are captured by the resin bed.
However, as the surface area of each bed in the resin is occupied by minerals, the water softener's effectiveness gradually decreases. A complete industrial water softening system must include regeneration equipment for these resin beds. Typically, a duplicate resin bed can be activated to give the primary resin bed time to refresh. After the water has been diverted to the second bed, the regeneration of the first bed can begin.
The other option is to stop the outflow of water during the regeneration process. This may be possible if the demand for softened water is limited to one or two shifts.
The resin has a much higher affinity for calcium and magnesium ions, but when rinsed with water containing a very high concentration of sodium ions (i.e., very "salty" water), the sodium ions replace the calcium and magnesium ions on the resin. Finally, the resin bed is flushed with water to remove any excess salt before it is returned to service.
What do water softeners remove?
Water softeners purify hard water by removing calcium and magnesium ions. The two minerals that cause water hardness are calcium (Ca2+) and magnesium (Mg2+). In addition, any positively charged ion will be attracted and eliminated during the ion exchange process (also known as a cation). Other minerals, such as iron and manganese, may be included.
Water softeners remove ferrous iron (dissolved iron) when it is present in small amounts and the majority of the iron is soluble. Iron darkens the colour of water and causes visible stains on your toilet, bathtub, and sinks. The removal of ferric iron (insoluble iron) with a softener is more difficult. Ferric iron will accumulate on the resin bed and resist the regeneration cycle's backwashing. This can result in iron slugs in your softened water, reducing the potency of the resin beds. When dissolved iron comes into contact with oxygen, it oxidises and transforms into ferric iron.
So, while a water softener can remove iron in its dissolved state, if your water contains a high concentration of iron, some of it will inevitably convert to an insoluble state. If your water softener is processing a lot of iron, you should use a chemical solution like “Rust Out” to clean your softener bed and extend the life of your resin beds. An iron filter or a more comprehensive filtration system, such as reverse osmosis, is best for removing iron from water.