History of Water Purification
Water purification has a deep history as humans realized that the best way to prevent illness from consuming life giving water was through a purification process to remove contaminants and salt. Some seventy percent of the world is water, but most of it is laden with salt. Even fresh water sources are more often than not contaminated with bacteria and parasites harmful or even deadly to humans. Out of this reality and need for clean water, water purification was born. From crude filtering with charcoal or other porous rocks to advanced reverse osmosis filtration, humans have devised numerous highly effective means of purifying the water we drink. Here is a look at some common processes.
Above and beyond everything, water needs to be desalinated–the salt removed. Even the most primitive humans knew that they simply could not ingest salinated water in large quantities to satisfy thirst–or remain living for that matter. Desalination treatment converts saltwater into freshwater and is used on some level most everywhere today, but has historically been invaluable in regions where converting seawater to freshwater was the primary source of potable water. As humans evolved, desalinating water reached beyond consumption and into the realm of agriculture as freshwater was needed to irrigate crops. Modern desalination on a large scale requires a large infrastructure and consumes a lot of energy to produce potable water.
Desalination removes salts, minerals, and chemicals from the water as well. The bi-product of such a process is a salty brine mixture that must be disposed of–usually through release back into the sea. This can cause a host of problems in and of itself in terms of damage to marine life and energy use, but large scale desalination is an important element of water purification. Desalination plants are essential to providing large quantities of clean water to municipalities–especially in drought prone areas and coastal regions.
These water purification systems rely on evaporation from the sun to provide clean water. As a very simple method of producing clean water, solar stills have a strong root in history and are still in use today. They work by using the rays of the sun to evaporate salty or contaminated water on an evaporation floor through a transparent cover on top of the floor. The result is clean water for drinking and irrigation. This process is one of the most time consuming–agonizingly so–but it is simple, cheap, reliably produces clean water, and can be implemented effectively on both a small and large scale.
Reverse osmosis processes remove salt and other minerals, chemicals, and other contaminants larger than a water molecule. These systems work by using high pressure to push water through a semipermeable membrane to separate water molecules from salt, chemicals, and contaminants. This process can also be energy intensive and wastes a lot of water in the process, but is able to remove a very high quantity of contaminants from water–making the water purer to the taste than unfiltered tap water. While 100 percent of contaminants can’t be removed from the water, these systems are highly reliable and with maintenance, can last.