About 71% of the Earth’s surface is water-covered, ranging from seas, salty oceans, and frozen Poles, to freshwater found in groundwater, rivers, and some lakes. Out of all the water on Earth, freshwater makes up about 3% only; yet, is it really safe to drink?
Several thousands of years ago, the answer could have been “Yes”; now, however, different pollutants have affected environmental resources, including water, and the answer is no longer “Yes”! Nowadays, in several developing, as well as developed countries, it would be rare to find a house without a water filter, to acquire fresh and clean water, prevent diseases, and enjoy great taste.
Water Treatment History
Water filters are regarded as a modern invention; in fact, the idea is ancient, dating back to when Man first learnt the importance of obtaining clean water to drink. The earliest documentation of water treatment was found in Sanskrit writings dating back to about 2000 years ago. Methods used then included boiling water or dipping heated metal tools into it to improve its taste, as in Ancient Times, people determined the purity of water by taste.
Later on, the famous Greek physician, Hippocrates, invented his own filter, which was made of a cloth pouch to trap sediments of boiled water and produce clean water. In 1627, a breakthrough occurred in the history of water treatment when Sir Francis Bacon invented the first seawater desalination and purification technique by means of sand filtration. Through the following centuries, water filtration evolved to the technology existing nowadays.
How do water filters work?
Water filters apply two basic techniques:
- Physical filtration is straining water by removing minute solid particles, whether organic deposits or chemical sediments.
- Chemical filtration involves passing water through an active material, which removes pollutants and sediments chemically as they pass through.
There are four types of water filters:
- Activated carbon filter is the most common household water filter, which is based on charcoal that removes impurities and sediments chemically from water. While great for removing all common water pollutants, including chlorine-based chemicals, activated carbon filters cannot cope with heavy metals, such as sodium; thus, the filters eventually clog up with impurities.
- Reverse osmosis filters passes water through a very fine membrane at high pressure, so contaminants remain behind.
- Ion-exchange filters are designed to split apart atoms of contaminating substances to make electrically charged ions, which exchange harmful ions for useful ones.
- Distillation filters purify water by boiling it; since water boils at a lower temperature than toxic heavy metals, they remain behind as the steam separates away and boils off. Unfortunately, some Volatile Organic Compounds (VOCs) boil at a lower temperature than water, which means that they evaporate with the steam and cannot be removed by the distillation process.
The main benefit of using water filters is obtaining safe drinking water with no impurities, harmful chemical compounds, or toxic metals, thereby improving health and reducing waterborne disease and cancer risks. Despite the wonderful benefits of water filters, they have some disadvantages if the disposable water filter cartridges are not replaced periodically. In this case, the filter does not work effectively, reduces useful salt and mineral amounts in water, and loses its utility.
References
historyofwaterfilters.com
allaboutwater.org
dwqr.scot
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