Water is as critical to the survival of humans as the air they breathe. As early as the emergence of
mankind, humans have worked tirelessly to secure and purify the water they drink. Water filtration
issues span the entire existence of the human race. Water filtration is defined as removing
impurities and contaminants, such as: lead, pesticides, or bacteria from water. Water filtration
takes on many forms. From basic sieves to advanced filtration tactics, the water filtration industry
is booming across the globe. If it were not for innovations in water filtration, humans would have
not evolved to their present state.
Before the common era
As far back as 2000 BCE, humans began to filter drinking water, mainly for better taste. Humans back
then understood that some water was gross or undrinkable, but they did not fully comprehend the
differences. During this period in history, people also began experimenting with early purification
methods, such as: boiling, straining and primitive filtration techniques.
Around 400 BCE, the invention of Hippocrate’s “sleeve” came about. This sleeve was a bag filter that
would trap sediment which was thought to be the cause of bad tasting and smelling water.
In 312 BCE, during the reign of the Romans, the invention of the aqueduct came about and was the first step to
revolutionizing the plumbing and water world. The aqueduct brought safe flowing water from natural sources, such as lakes, and springs. Unfortunately the Dark Ages did not bring many advancements in water filtration.
The common era
During the early seventeenth century, Sir Francis Bacon started experimenting with desalinating salt water, but he was unsuccessful in his attempts. Although he was unsuccessful, his attempts sparked interest in creating future water filtration technologies. In the latter part of the seventeenth century, advancements in microscopes allowed for water to be visible with the naked eye, under a microscope, and within this century water filters began to enter the consumer market.
When an epidemic of cholera broke out in London, England in 1854, people in areas with sand based
water filters were discovered to be less affected by the bacteria. A British scientist, John Snow, found that pumps thought to contain fresh water were contaminated by water pumped from the Thames river which was polluted with sewage. The immediate solution was to use private water wells not connected to the Thames river. He later discovered chlorine could disinfect water contaminated by sewage. It wasn't until 1897 that Maidstone would be the first town in England to have its entire water supply treated with chlorine.
Chlorine was first used successfully as a disinfectant for a municiple water source in the United States in 1908 in Jersey City, New Jersey. A physician trained in bacteriology, John L. Leal, was the sanitary advisor for Jersey City and hired George W. Fuller to construct a chlorination plant to disinfect their water reservoir. This technology of using chlorine disinfection contributed to the eradication of typhoid fever, as well as other waterborne contaminants. This discovery inspired cities to implement filtration to their water supplies, and also inspired the first federal regulations on public water supplies. However, these more extensive water safety mandates and restrictions would take decades to surface. It wasn't until 1974 the Safe Drinking Water Act (SDWA) was passed into law to protect the water quality of all water sources above or below ground designed for drinking water use.
Water softening in the 20th century
At the start of the 20th century, the invention of water softening for water desalination ended up being an amazing technique for filtering water. The emergence of ion exchange technology spurned a water treatment market. Magnesium and calcium ions are the cause of water hardness. Water softeners use positively charged ions called ‘cations.’ Ion exchange refers to the process of exchanging hard ions to non-hard ions, by replacing the magnesium and calcium (hard) ions with either sodium or potassium (soft) ions.
A water softener tank is filled with cation resin beads. The sodium or potassium ions attach to the cation resin beads when the resin is flushed with water containing dissolved sodium or potassium, whichever is being used. As hard water passes through the water softener tank, the magnesium and calcium ions attach to the cation beads and release the sodium or potasium ions into the water. When the sodium or potassium ions reach the point where they can no longer make an exchange for the magnesium and calcite the softener needs to be regenerated. The regeneration cycle backwashes a salt (or potassium) brine solution through the water softener so that the magnesium and calcium ions are overpowered and replaced with sodium (or potassium) ions. Regeneration timing depends on how the water softener control head is programmed according to how much water is being softened. Take a look at our Fabulous Soft-Economizer Water Softeners for effective removal of magnesium and calcium ions in your water.
Methods of water filtration
Once water testing technology was invented, many more inventions in water filtration came about. Listed below are some of the most common filtration methods available on the market today.
Activated Carbon/Charcoal – Activated charcoal is made by heating the charcoal to an extremely high temperature thus changing it's original structure to expand its surface area and make it more porous. When a liquid is introduced, pollutants contained in the liguid get trapped inside the pores. This method of filtration reduces chemical contaminates such as chlorine, organic compounds, and volatile organic compounds (VOC's) from the water. However, this method does not remove or reduce inorganic compounds, or solids, such as salt, calcium, magnesium, nitrates, or silica.
Activated Aluminum Oxide – More commonly known as granulated activated alumina. This method also uses heating activation to maximize the amount of pores the compound contains. These pores are designed to trap heavy concentrations of arsenic, selenium, and fluoride. One of the downsides is that depending on the water’s pH level, and the composition of the water, this could allow for aluminum to leach into the water.
- Ceramic Filter – Ceramic filters are composed of many small pores. Water passes through the pores
and removes anything larger out of the passing water. This method of filtration can be effective for filtering out bacteria, but not effective against filtering out viruses. Giardia cysts, and cryptosporidium parasites can be removed by mechanical means if the micron rating is 1.0 or smaller. Most ceramic filters can be cleaned with water and a damp cloth and reused.
- Reverse Osmosis Filter – This method of filtration most commonly uses a semipermeable membrane without
definable pores, only spaces between fibers of thin film composites from which the membrane is made. Most membranes consist of multiple layers of polyamides and pourous polysulphones, which surround a perferated collection tube. Water can pass through the membrane while trapping solid contaminants like salt ions, or other organic solids away from the water. Typically, reverse osmosis membranes can remove 90% to 99% of total dissolved solids (TDS) in water passing through them. Although these membranes can reduce dissolved solids they are not capable of removing liquid chemicals or volatile organic compounds (VOCs) such as industrial solvents, petroleum fuels, hydraulic fluids, pesticides, and paint thinners to name a few.
View our Kwik Change Reverse Osmosis Systems for a very effective way to remove dissolved solids from your water.
UV Purification – Microorganisms are eliminated by using a high frequency light and a glass element for water to pass through. This method of filtration is the most effective at eliminating bacteria, parasites and viruses. This method can be costly as it takes electricity to operate and it does not remove chemical, metal, and other contaminants such as: fluoride, chlorine, lead or pesticides.
Water Distillation - Water is boiled until it turns into steam, the steam vapor is then cooled back down to
a liquid state in a separate container. This method is very effective at removing contaminants and killing germs. The water quality is improved and there is no filter that needs replacing. Unfortunately, the distilling process removes important minerals like magnesium, calcium and sodium that give water its flavor, so the taste may be less than favorable from what you might expect. Since distilled water is so pure it becomes aggressive in the sense it will obsorb any minerals it comes into contact with. Although effective for obtaining purified water, this process is very slow and requires electricity to operate.
Types of water filters
In the paragraphs below, we discuss the different types of water filters that use the filtration methods described above.
Water pitcher filters are the most cost effective and common water filter options. Although these filters remove many contaminants from the water, they are very slow and limited in capacity. They can also take up valuble space in your refrigerator. Most water pitchers use the activated carbon filtration method for water purification.
This type of water filter is best used in areas with generally safe and clean water. The filter attaches to an existing faucet and provides filtered water free of contaminants. It helps improve the taste and smell of water and is relatively inexpensive.
Under Sink Filter
Under sink water filters are installed directly under a sink. Almost all point of use filter systems are designed to fit under your kitchen sink. This is when you will need to do some research to determine which contaminants concern you the most and what type of filter will be best for your household. Whether you are on a private well or hooked up to a municipal water system, the first thing you need to find out is the quality of your drinking water. It may turn out your water quality is better than you think it is or maybe you just need to reduce the chlorine taste that is added to the water to kill any possible bacteria. These type of filters can take up some space under your sink, but the payoff more than makes up for it. Anyone with a little plumbing knowledge can install them. However, if you do require a professional installation from a plumber it can cost a little more compared to some of the other options.
Check out our ultraviolet, and reverse osmosis under sink counter filters to help keep your water safe.
Whole House Filter
Whole house water filters are the most expensive option, but if you reside in an area where water is hazardously unsafe, then these types of filters can be crucial for your safety and peace of mind. These filters are commonly installed on the main water supply to your home. Typically, whole house water filter systems are very large because they supply water for your entire home instead of just point of use. These filters usually require a plumber or experienced handyman to install, and will require some regular maintenance and filter replacements.
Water filtration options vary widely due to so many different types of minerals and contaminants found in water sources. And, unfortunately, no one filter can remove all of the problems found in water. Specific filters are required for specific water conditions which can lead to needing more than one type of filter for some water sources. The good news is many advancements in water filter technologies continue with increased interest in water purity. As technology continues to improve, water filtration is bound to improve along with it.
If you would like to build your own filter with many varied methods of filtration, take a look at our Top Quality Cold Water Filters.
For hot water filters, check out this page.