The History of Water Filtration
Water filtration has become such an integral part of our existence that we hardly realize how fast technology is changing. Occasionally it is good to take a step back and look at where we have come from and the brilliant minds that got us here. Starting from the beginning.
Who Invented the Water Filter?
It is hard to pin down, given water filtration has been around for many years, before record-keeping was streamlined. However, the first documented inventor of a water filter is Hippocrates, the father of medicine and the inventor of the Hippocratic sleeve.
History of Water Filtration
Water purification did not pick up nearly as fast as we can now tell it should have. The amount of water seemed to be more important than the quality in ancient times. Taste clarity and occasionally odor of water were taken to as justification for purity. The connection between death, disease, and water was not made until much later.
Water treatment traces its roots back to 1500 BC in Ancient Egypt, when they first practiced the principle of coagulation. They would use the chemical alum to settle particles suspended in the water. There is evidence of these practices in pictures found in their ancient tombs, specifically, Ramses II and Amenophis II at Thebes.
Before this, there are no verifiable timelines, but there is enough evidence to show they knew about water purification. Ancient Greek writings and Indian Sanskrit dating back as far as 2000 BC recommend water treatment methods.
They seem educated about boiling and straining water, sand and gravel filtration, and the purification effects of boiling water. They were more concerned about addressing the turbidity of water than chemical contaminants and pathogens.
The next major event is discovering the healing power of water by Hippocrates, the famous Greek physician, in 500BC. He started conducting his own water purification experiments. He would recommend a bath in cool water for his feverish patients. The bath was supposed to realign the temperature and harmony of the four humors or essential fluids of the body.
He also trusted that good taste means water was clean and pure. He designed a crude water filter to purify the water he would use on his patients. This was a cloth bag through which water would be poured after being boiled, trapping any sediments causing a bad odor or taste. This famous bag is commonly known as the Hippocratic sleeve.
There are other less famous but significant historical water treatment methods:
- The drinking cup by a 9th century BC Spartan lawgiver was designed to hide the color of the water from its user so you could drink from it without qualms. The mud would stick to the sides of the cup.
- There was a phase when water was boiled before being transported to battlefields and filtering via wick siphons.
- The Greeks and Romans were also busy devising methods to manipulate tastes and odors in water. Diophanes of the 1st Century BC came up with putting macerated aromatic shrubs in rainwater.
- In the 1st Century AD, Paxamus proposed to pack bruised coral or pounded barley in a bag and immerse it in bad-tasting water.
- Gerber, an Arabian alchemist from the 8th Century AD, proposed various stills for purifying water that applied wick siphons to get water from one vessel to another.
The Dark Ages
During the Middle Ages (between 500 and 1500 AD), water supply became less sophisticated, and very few experiments were done in water purification or filtration. Following the crumbling of the Roman Empire, their impressive aqueducts were vandalized by enemy forces, and others were no longer in use. The future of water treatment was bleak.
The period was marked by devout Catholicism throughout Europe. It is referred to as the Dark Ages because of the lack of scientific innovations and experiments.
The late 14th century saw the beginning of the Renaissance period, which saw an end to the intellectual and scientific stagnation that marred the dark ages. It is often referred to as the Age of Discovery as it featured many inventions that would impact the world.
The Foundations of Desalination
In 1627, Sir Francis Bacon began experimenting with seawater desalination. He believed if seawater was allowed to percolate through the sand, it could be purified.
He believed that if he dug a hole near the shore to let seawater through, the sand particles, which are heavier than the salt particles, would block the salt as the water passed through to the other side of the hole. The water would come out on the other side pure and salt-free.
The experiment failed, and he was left with salty, undrinkable water. He, however, managed to rejuvenate water filter experimentation by many scientists.
Discovery of the Microscope
It began with Zacharias Janssen and his son Hans, two Dutch spectacle makers experimenting with lenses in a tube who realized they could magnify objects viewed through the tube. This was the foundation of the current microscopes and telescopes.
Anton Van Leeuwenhoek would build on this a century later and reach magnification levels of up to 270 times the original object. This revolutionized water purification in a big way.
In 1676 he used his discovery to see and describe life in a single drop of water. The first sighting of microorganisms.
Enter Domestic Water Filters
The 1700s saw the application of the first water filters for domestic use, which were made out of wool sponge and charcoal. In the mid-1700, Joseph Amy obtained the first patent for these water filters. They were available for sale by 1750.
The first scientific studies on softening were performed in the 1800s when scientists noted some clays could adsorb ammonia from soil and decolorize liquid manure. The Royal Agriculture Society of London had figured out the documented the ion exchange process in the middle 1850s
Clays, zeolites, humic acids, and glauconites (greensands) were later identified as the materials responsible for the base exchange. They were trying to figure out if ion exchange could turn lead into gold. The research paid off in ways they did not envision.
German scientists Harm, and Rumpler made the first synthetic ion exchangers in 1903. This concept would later be used to remove lead, mercury, and other heavy metals from water.
Water treatment had changed focus from prevention of diseases to the creation of softer and less mineralized water. This time coincided with the initial stages of the industrial revolution.
Increased use of steam birthed the need to eliminate or drastically reduce scale formation. Lime and soda ash assisted in removing temporary hardness, but they were messy, not user-friendly, and the softness was not sustainable. They tried aluminosilicates which are superior in terms of capacity to clay. These would dissolve gradually during use which was not sustainable.
Adams and Holmes discovered that sulfonated coal was stable and had a high capacity for cation exchange. This was the basis for a large industry specializing in removing hardness from boiler feed water and the genesis of the modern softener we now know.
In 1935, Adams and Holmes noticed some synthetic vinyl compounds could be sulfonated as well. These were polystyrene resins. This was the foundation of almost every organic-based ion exchanger today. The polystyrene-based sulfonic acid resins were exceptionally high capacity, versatile and stable. Versions of them are still used today.
Softener use expanded from boiler feeder water to laundromats because hardness ions lessen the ability of soap to lather or lift dirt from clothing. Soft water, on the other hand, requires substantially less soap in comparison, which saves resources.
Boiler feedwater and laundry make-up application are still the leading consumers of soft water. Other significant contributors are car washes, window washing operations, and pre-treatment of reverse osmosis membranes.
History of Ceramic Filtration
John Doulton, a potter from Lambeth, England, influenced by the Industrial Revolution, sought an industrial application for his ceramic technology. By 1827, the first Doulton water filters were made using various earth and clay material.
The company got a shot in the arm when Queen Victoria commissioned Doulton to produce a water filter for the royal household in 1835. Doulton went out of his way, incorporating his fine china-making skills and ceramic filter technology to make an impressive gravity-fed stoneware filter.
The Queen was impressed and granted Doulton the right to stamp the royal crest on his stoneware water filters, and the Doulton Filters became a household name
The next milestone was introducing the Doulton Manganous Carbon water filter in 1862, the year Louis Pasteur conclusively disproved the myth of spontaneous generation. This allowed researchers to focus on creating porous ceramics capable of filtering out microorganisms from water.
In 1906 Doulton introduced a filter equal to the one Lois Pasteur had developed in France, which was instantly embraced by hospitals, laboratories, and for domestic use worldwide.
Ceramic filters are now mostly made for point-of-use applications, although they are marketed for centralized water treatment systems.
The Origins of Public Water Treatment
The first large municipal water treatment plant designed by Robert Thom was installed in Scotland in 1804 to give every resident access to treated water. The treatment was based on slow sand filtration, and the water was distributed by horse and cart. The first pipes were installed three years later.
This planted the seed that everybody deserved access to clean drinking water. The idea took a while to be implemented in other parts of the world, though.
A municipal water treatment plant of a similar pattern was installed in London in 1829
Diseases became rampant in mid-19th century London due to tight quarters for workers. City officials started to connect the spread of cholera with poor drinking water quality. Areas where the sand water filters had been installed, seemed to be escaping the worst of the outbreak.
In 1854, British scientist John Snow discovered that cholera was being spread through contaminated water. One of the water pumps had been contaminated by sewage water. The discovery would have a huge impact on how water treatment and disinfection would be managed in the future.
He used chlorine to kill the bacteria, which initiated water chlorination as a disinfection process. He disproved the belief that good-tasting water is automatically pure water. The British government mandated the installation of sand water filters throughout the city in one of the first shows of government regulation of public water.
The sand filtration method was adopted in the United States in the 1880s. They used backwashes to clean the filter media and mechanical agitators to loosen the debris, increasing their treatment capacity. They used charcoal filtration to improve the taste and odor.
They experimented with rapid as opposed to slow sand filtration with their increased filter capacity and found it more efficient and effective. They introduced a powerful jet stream to clean it up, increasing the number of people who could benefit from the plant. The increased water treatment and chlorination rapidly reduced the outbreak of waterborne illnesses like typhoid and cholera in the early 20th century.
Unfortunately, the negative bit of chlorination showed up with time. Chlorine is more volatile than water and was linked to respiratory diseases. The experts were once more on the lookout for alternate water disinfectants.
In 1902, the Belgians mixed calcium hypochlorite and ferric chloride, and it was able to coagulate and disinfect.
In 1906, ozone was applied as a disinfectant in France
People have also been installing home water filters and shower filters to protect themselves from the effects of chlorine.
The Beginning of Regulations
The importance of drinking water standards became evident as municipal water treatment was adopted all over the United States. The first standards to be implemented for public water date back to 1914 but actual municipal drinking water standards application only started in the 1940s
The most significant push came in the 1970s with heightened public concerns about deteriorating city air, litter, and contamination of urban water supply with dangerous impurities. This forced President Richard Nixon to address the House and Senate about it and led to the formation of the Environmental Protection Agency (EPA).
The Clean Water Act requiring industries to improve their waste processes to limit the effects of contaminants on freshwater sources passed through congress and became law in 1972.
Two years later, the Safe Drinking Water Act was adopted by all the 50 states, regulating public water systems within their jurisdictions. It identifies contaminants that should be monitored and reported to consumers if they exceed certain thresholds.
Public health concerns have since shifted from waterborne illnesses caused by disease-causing microorganisms to anthropogenic water pollution like organic chemicals, industrial sludge, and pesticide residues. The focus of regulation is on waste management and water contamination.
The federal, state, and municipal governments all play a role in monitoring drinking water and enforcing compliance to present regulations.