Water purification methods remove impurities to provide safer water. Both boiling and distillation treat water, but they achieve different levels of purification. Understanding these differences is important for selecting the appropriate water for specific needs.
Boiled Water: Process and Characteristics
Boiling water involves heating it to a rolling boil for at least one minute (three minutes at altitudes above 6,500 feet) to inactivate most harmful microorganisms. This thermal treatment destroys bacteria, viruses, and protozoa by denaturing proteins and disrupting their cellular structures.
Despite its effectiveness against biological contaminants, boiling does not remove dissolved inorganic substances or chemicals. Minerals, salts, heavy metals (like lead or arsenic), and various industrial chemicals remain because they do not evaporate. Boiled water is microbiologically safe but retains its original dissolved solid content.
Distilled Water: Process and Characteristics
Distillation is a more comprehensive purification method mimicking the natural water cycle, involving evaporation and condensation. Water is heated to its boiling point, converting it into steam. This steam rises, leaving behind virtually all non-volatile impurities, including dissolved minerals, salts, heavy metals, and most chemicals.
The purified steam is collected and cooled in a separate condenser, reverting back into liquid water. This condensed liquid is distilled water, characterized by its high purity. Distillation produces water significantly purer than boiled water, containing extremely low levels of dissolved solids and contaminants.
Comparing Boiled and Distilled Water: Purity and Uses
The primary difference between boiled and distilled water lies in their purity regarding dissolved solids. Boiled water is free of most microorganisms but retains minerals and other non-volatile substances. Distilled water, through vaporization and condensation, is essentially devoid of these impurities, making it a much purer form of H₂O.
Given these distinctions, each type of water has specific applications. Boiled water is suitable for immediate consumption in emergencies where microbial contamination is a concern, such as after a natural disaster. It is also used for sterilizing items like baby bottles or for cooking, where minerals are not detrimental.
Distilled water, with its high purity, is preferred for applications where mineral buildup or chemical residues are undesirable. This includes medical equipment (like CPAP machines), laboratory experiments, and automotive uses (such as car batteries and cooling systems). It is also used in humidifiers and steam irons to prevent scale accumulation. While safe to drink, distilled water lacks the beneficial minerals found in tap water, which some consider a disadvantage for regular consumption.