Water purity is a topic often leading to confusion, especially when distinguishing between distilled and purified water. While both types undergo processing to achieve a cleaner state, their methods of preparation and final characteristics differ notably. Understanding these differences can help clarify their appropriate uses and implications.
Understanding Distilled Water
Distilled water is produced through a process called distillation, which mimics the natural water cycle. This method involves boiling water, turning it into steam, and then cooling the steam to condense it back into liquid form. As water transforms into steam, impurities such as minerals, salts, heavy metals, and many organic compounds are left behind in the boiling chamber. The resulting condensed water is highly pure, characterized by its virtually complete absence of dissolved solids and an extremely low concentration of dissolved minerals.
Understanding Purified Water
Purified water refers to water that has undergone various treatment processes to remove impurities, meeting specific quality standards; the exact methods used can vary. Common purification techniques include reverse osmosis (RO), which forces water through a semi-permeable membrane to filter out dissolved solids. Deionization (DI) uses ion-exchange resins to remove charged atomic particles. Activated carbon filtration is often employed to remove chlorine, sediment, and volatile organic compounds, while ultraviolet (UV) sterilization can destroy microorganisms. Purified water, depending on the combination of methods used, is generally free of chemicals and contaminants, and often has significantly reduced mineral content, adhering to stringent quality benchmarks.
Core Differences
The primary distinctions between distilled and purified water lie in their production methodology, resulting purity levels, and mineral content. Distillation is a specific, single-process method that physically separates water from its dissolved impurities by phase change. In contrast, purified water can be produced using one or a combination of several advanced filtration and treatment processes.
Distilled water typically achieves an extremely high level of purity, often containing less than one part per million (ppm) of total dissolved solids (TDS). Purified water also boasts a high purity, but its TDS level can vary depending on the specific purification methods employed, generally ranging from one to ten ppm. While purified water has significantly reduced mineral content compared to tap water, some methods may leave trace amounts. The absence of minerals in distilled water can also result in a flat taste, whereas purified water might retain a more familiar taste due to any remaining trace minerals.
Common Applications
Each type of water finds its niche based on its purity. Distilled water is frequently utilized in applications where the absence of minerals and other dissolved solids is paramount to prevent buildup or interference. This includes medical devices like CPAP machines, car batteries, cooling systems, and laboratory experiments requiring a highly pure solvent. It is also preferred for steam irons and humidifiers to prevent the accumulation of mineral deposits that can damage equipment.
Purified water, on the other hand, is widely consumed as bottled drinking water due to its cleanliness and often palatable taste. It is also extensively used in the food and beverage industry and various industrial processes where high-quality, contaminant-free water is required.
Health Implications
Both distilled and purified water are generally considered safe for consumption. Purified water, with most contaminants removed, is a common choice for drinking and often preferred for its taste, which can be influenced by the presence of trace minerals. Distilled water, due to its nearly complete lack of minerals, has been a subject of discussion regarding long-term consumption. While it does not inherently pose a health risk for occasional drinking, it does not contribute to dietary mineral intake. The choice between the two for drinking often comes down to personal preference and individual dietary needs.