About 60% of the United States has hard water supply. This means that it has high levels of magnesium and calcium that exist in the form of carbonates. This is contributed by leaching of rainwater through limestone rocks.
The most efficient and effective way of overcoming the effects of hard water is softening it through ion exchange processes through the use of water softeners. Although the use of ion exchange water softening method has several environmental impacts, the benefits are higher such as energy savings and a reduction in the consumption of detergents.
According to work published in France, heating efficiency can be reduced by a 1mm increase in scale thickness by an average of 6%. Another study conducted by New Mexico indicated that gas heaters running on hard water consumed 29% more energy. Electric heaters using hard water consumed 21% more energy.
Consumption of detergents and cleaning agents
It has been observed that soaps and detergents are used more than double in hard water. This is because hard water does not lather easily and create foam. To factor in the presence of hard water, detergent manufacturers add more phosphates. The environmental burden of bathing and laundry is increased with the softening additives and additional detergents. Since hard water has scaling effects on sanitary products, anti scalants are often added in areas that have hard water. Anti scalants tend to be acid based and costly thus have an environmental impact.
Studies have shown that softening of water increases the life of household items such as bath towels, pillow slips, and sheets by 40%. These are items that are frequently washed.
Environmental impact of softening
Consumption of raw materials
Equipment used for softening is manufactured from several materials such as plastics and metals which are highly recyclable. This equipment serves for many years and requires less maintenance. The only consumable product used during the water softening process is salt. Salt is an abundant commodity in nature including the vast geological deposits in the sea. Salt is easily extracted and processed. The only environmental impact is the energy used up during evaporation.
The water softening regeneration cycle discharges certain amounts of sodium chloride to drainage systems. This occurs as the sodium ions are added during the softening process. Studies done on sewage systems and septic tanks indicate that salt has no harmful implications. There are no long term environmental impacts since salt does not bio-accumulate. Modern water softening equipment has been designed with high salt efficiency. Therefore, the overall effect of sodium on the environment is highly minimized.
The backwash and regeneration cycles of water softening consume standard amounts of water. With the modern equipment driven by demand, wastage is kept to a minimum.
Soft water and metal corrosion
Naturally, soft water has always been associated with an increase in the corrosion of water supply equipment and systems. As such, there have been concerns that soft water might impact negatively on metal. However, the results of tests undertaken bv the US environment protection agency established that there are no significant effects on corrosion between softened water and hard water from the source.
There is a clear indication that soft water has minimal impacts on the environment as compared to hard water. With modern water softening processes, the soft water will have almost negligible impact on the environment.