Water HardnessThe water supply in most of Arizona is considered "hard." Water hardness is a measurement of its calcium and magnesium bicarbonates, which together represent "Total Hardness." These hardness minerals create scale build-up inside pipes and appliances that gradually reduce water flow and efficiency. They also react with soaps and detergents to form soap curd, an insoluable material that clings to skin and fabrics, dulling fabric colors, making them brittle, and shortening their life. This formation requires greater soap or detergent usage and leaves a soap scum and stain that adds to cleaning chores. To establish uniform degrees of hardness, the U. S. Department of the Interior has established the following hardness levels.
|Soft||Under 1.0||Under 17|
|Slightly Hard||1.0 - 3.5||17 - 60|
|Moderately Hard||3.5 - 7.0||61 - 120|
|Hard||7.0 - 10.5||121 - 180|
|Very Hard||Over 10.5||Over 180|
Water softening involves an ion exchange process to replace the scale-forming calcium and magnesium ions with non-scaling sodium or potassium ions. The exchange takes place as the water passes through a bed of cation exchange resin that has been charged with a brine solution. The calcium and magnesium ions are attracted to the brine charged resin and held while a chemically equivalent amount of sodium or potassium is released into the water. In time, the brine solution will be expended and must be replenished through a regeneration process.
In an automatic softener, the new brine solution is supplied from a brine tank where it is generated by sodium or potassium chloride. It is flushed through the resin bed to drive out the hardness minerals. A control valve directs the flow of water through the cycle of service and regeneration. Regeneration is generally initiated by a demand sensor unit that either measures total water flow since the previous regeneration or uses a sensing probe to signal the end of a softening run.
Portable exchange (PE) softeners are also available from dealers who supply tanks of resin that have been regenerated at a central processing plant.
Basically, softeners do not add salt to the water since the process maintains the water's original level of total dissolved solids (TDS). It involves the exchange of one type of salt for another. Calcium is being eliminated, while sodium or potassium is being added. For sodium, the amount added is generally less than what is already present in the water from its natural sources, particularly in the Phoenix area, known as the Salt River valley. Sodium reduction from water is available through such purification processes as reverse osmosis or distillation.
Reverse osmosis systems are the most common type of water purification in Arizona, due to the generally high level of dissolved solids in the source water. Such units involve a multi-stage process and usually fit under the kitchen sink, supplying water to a holding tank and probably to a refrigerator. Water goes through a sediment filter to remove relatively larger particulates, then through a carbon filter to remove organic materials and chlorine before being forced through the walls of a semi-permeable membrane to remove the inorganic ions of salts and metals. There are often additional carbon filters units to further process the water and some RO systems involve different component configurations.
An alternative to reverse osmosis treatment is distillation. With this treatment, water is boiled in a heating chamber, vaporizing it and leaving the dissolved solids behind. The purified water vapor is then condensed back into a liquid and sent to a holding tank. Distillation systems also involve various filtration stages.
Recent concerns have been raised over increasing salinity levels of water as it is used and returned to wastewater treatment plants for processing. Water softeners are one of many sources contributing to such higher salinity levels. Since the source water in the state has also increased in salinity, wastewater salinity is automatically higher without any additional contributing sources.
Water softeners discharge salts to the drain during regeneration, as the trapped calcium and magnesium is flushed from the resin beads by a brine solution so that the softening process can continue. Some softeners discharge more salinity than others, particularly entry-level models with less efficient timer-clock metering systems.
In some areas, regulatory authorities have enacted restrictions against the use of automatic water softeners to reduce the salinity of wastewater. Even in such locations, water softening is still available with the use of portable exchange units that are regenerated at a central processing plant. No restricted areas are located in Arizona. Although there is concern for wastewater salinity in the state, authorities are focusing on the most efficient use of softeners instead of restricting their use.
Consumers can help by insuring that their softeners are adjusted to the most efficient settings and by replacing timer-clock meters with newer electronic models. This will help to reduce the number of regenerations needed by the softener, reducing the amount of salinity entering the wastewater stream and reducing the amount of water and salts needed for softener operation.
If you have questions about your softener settings and operation, contact your water treatment dealer or the Arizona Water Quality Association.
Alternative (Physical) Water Conditioning
The water supply in Arizona, like that in many other states, is considered "hard." Water hardness is created by calcium and magnesium bicarbonates in the water. One of the more confusing aspects of water treatment has been the claim by some water conditioning firms that their products are able to alleviate hard water problems without removing the calcium and magnesium ions from the water. These "alternative" products include magnetic, catalytic, electric, and electrodialysis conditioners.
In various ways, these products attempt to "suspend" or alter the characteristics of the calcium and magnesium ions. Phrases such as altering the electronic structure of water molecules, diminishing the electrostatic tension forces on the surfaces of the zones of strong ionization, and modifies the structure of the molecules of minerals and salts in the water are commonly used to describe the work of these units. Most of these products introduce energy to the water supply, either from a magnetic field or direct current, while catalytic units apply the properties of different metallic elements in trying to affect the ions.
These units are not water softeners. Softening the water removes calcium and magnesium to the point where the water tests at less than one grain per gallon of hardness. This is achieved through the ion exchange process of a water softener which removes the scale forming salts by exchanging them for a non-scale forming salt (either sodium chloride or potassium chloride) as the water passes through a cation exchange resin bed. The total salt level of the water remains the same. The amount of sodium or potassium added depends on the concentration of calcium and magnesium to be removed. It is insignificant for most consumers, especially when compared to the sodium levels already present in the water, particular in the Phoenix area (the "Salt River" valley).
The alternative conditioners attempt to be scale inhibitors, trying to deal with one of the problems created by hard water. If the calcium and magnesium ions can be successfully suspended in the water, their ability to create scale deposits can be diminished. However, since the ions are still present in the water, the water is still hard and the other problems associated with hard water, particularly involving various cleaning tasks, continue to exist.
Unfortunately, most alternative conditioner firms offer no independent confirmation of their product's ability to create any suspension of the calcium and magnesium ions or reduce the scale formation of hard water. On the contrary, there are numerous studies of these devices, particularly magnetic and catalytic units, reporting that no scale reduction ever took place.
One unit, employing a "di-polar" process, is an exception and has been shown to reduce scale formation.
Despite the limitations of these products and their record of non-performance, firms marketing them continue to describe the "breakthrough" they have achieved, expecting consumers to believe their claims despite the absence of any independent testing to confirm them. To further complicate matters, many of these devices have been packaged with other elements, like carbon filtration, so that claims for water purification can be made. Carbon is a recognized water filtration agent, but it is limited in what it removes from the water. In addition, carbon filters are not permanent devices and the carbon must be replaced periodically to avoid possible bacteria growth in the filter.
For effective removal of most potential water impurities, including sodium, such purification products as reverse osmosis or distillation in combination with carbon filtration are generally recommended.