Alkalinity of Drinking Water Explained
Understanding Alkalinity in Drinking Water
H1: The Concept of Alkalinity in Water
Alkalinity is a measure of water’s ability to neutralize acids. This property is determined by the presence of certain ions, including hydroxides, carbonates, and bicarbonates. Hydroxide ions, though typically found in low concentrations, are always present in water. However, significant amounts of hydroxides are rare in natural water supplies, unless the water has undergone specific treatments.
H2: Sources of Alkalinity in Water
Carbonates are found in natural water supplies in some regions, but their concentrations usually do not exceed 3 or 4 grains per gallon (gpg). They may also appear after lime soda treatment for water softening. Bicarbonates are the most common source of alkalinity, with nearly all natural water supplies containing measurable amounts, ranging from 0 to about 50 gpg.
H3: Detecting Alkalinity
Alkaline substances in water, such as hydroxides or bases, can be detected by their bitter taste and their ability to turn red litmus paper blue. Phosphates and silicates are rarely found in significant concentrations in natural water supplies, but compounds containing these ions are used in various water treatment processes.
H2: Importance of Alkalinity in Water Supplies
Moderate levels of alkalinity are beneficial in water supplies as they balance the corrosive effects of acidity. However, excessive quantities can lead to several issues. Alkaline ions are present in water but are balanced by cations like acidity, magnesium, and sodium or potassium.
H3: Impact of Alkalinity on Taste and Skin
You may not notice an alkaline condition unless bicarbonate ions are present in large amounts. Even small amounts of carbonate and hydroxide ions can be detected. Strong alkaline water can have an unpleasant "soda" taste. Moreover, highly mineralized alkaline waters can cause excessive drying of the skin by removing normal skin oils.
H2: Environmental Protection Agency (EPA) Regulations
The EPA Secondary Drinking Water Regulations limit alkalinity based on total dissolved solids (500 parts per million) and pH value. These regulations ensure that water is safe for consumption and does not have an objectionable taste.
H1: Methods to Remove Excessive Alkalinity
Troublesome amounts of alkalinity can be removed using reverse osmosis technology, which also eliminates other total dissolved solids. This method is more suitable for household use compared to distillation and deionization, which are expensive and require more space. Reverse osmosis systems can be installed under the kitchen sink or on countertops.
H3: Alternative Water Treatment Methods
Other methods to remove alkalinity include lime softening, which removes hardness and precipitates an equivalent amount of alkalinity. However, this method is typically used in industrial and municipal installations. An anion resin regenerated with sodium chloride can remove most anions, including carbonates, bicarbonates, and sulfates, but it can result in high chloride ion concentrations.
H2: Chemical Treatments for Alkalinity
Feeding a mineral acid, such as hydrochloric or sulfuric acid, can neutralize water’s alkalinity by converting bicarbonates and carbonates into carbonic acid. However, this process requires careful control and handling of strong acids, and it’s necessary to allow the resulting carbon dioxide gas to escape into the atmosphere.
H1: Conclusion
In conclusion, understanding the concept of alkalinity in drinking water is crucial for maintaining water quality and ensuring it is safe for consumption. While moderate levels of alkalinity are beneficial, excessive amounts can cause problems that affect taste, skin health, and overall water quality. Employing appropriate water treatment methods can help manage alkalinity levels effectively.