National Environmental Services Center
West Virginia University
P.O. Box 6064
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26506-6064


Search for Clean Water Continues

by Kathy Jesperson
On Tap Editor

Editor’s note: This is the first installment of a three-part series on the history of water treatment and waterborne diseases. The subject was suggestedby a respondent to On Tap’s readership survey. In this first article, we’ll look at our quest for clean drinking water from ancient times to the present, using various water treatment methods. While there is no way we can touch on every water treatment known to humankind, we can illustrate that humans have always had a thirst for clean water.

Long before humans learned to rub two sticks together to make fire or took a hammer and chisel in hand to carve out the first wheel, they thirsted for pure drinking water. As we find ourselves in awe of the latest contaminant treatment methods and detection devices, it is easy to forget that the desire for pure drinking water is not a modern phenomenon. Evidence from almost all historical periods suggests that people took measures to ensure a fresh drink of water.

But sometimes that drink came with more than its thirst quenching qualities. Early humans thought that the taste of the water determined its purity, and they did not consider that even the best tasting water could contain disease-causing organisms. We know now that just because water tastes good, it is not necessarily safe to drink. However, the efforts of these water treatment pioneers were not in vain. It was through their trials and errors that we now know how to make water safe to drink.

Image Caption: This ancient Egyptian clarifying device was found pictured on the wall of the tomb of Amenophis II at Thebes. The inscription was carved in 1450 B.C.
Reprinted from The Quest for Pure Water. The history of the 20th Century, by permission. Copyright 1981, American Water Works Association

Centuries Old Quest Continues
According to the American Water Works Association’s (AWWA) two-volume 1981 textbook, The Quest for Pure Water: The History of Water Purification from the Earliest Records to the Twentieth Century by M.N. Baker and Michael Taras, “Man has persistently pursued ‘pure’ water for thousands of years.” They speculated that this “quest” for pure water must have begun in prehistoric times. But the earliest water treatment records come from Sanskrit writings and Egyptian inscriptions.

The Sus’ruta Samhita, Sanskrit writings about medical concerns, dates from approximately 2000 B.C. and offers evidence that water treatment may well be as ancient as humans are. The writings declare that “impure water should be purified by being boiled over a fire, or being heated in the sun, or by dipping a heated iron into it, or it may be purified by filtration through sand and coarse gravel and then allowed to cool.” Other purification methods included the use of a kind of stone, known as “Gomedaka,” and the seed of Strychnos potatorum.

In 1905, Francis Evelyn Place, who studied Sanskrit medical lore, wrote, “It is good to keep water in copper vessels, to expose it to sunlight, and filter through charcoal.” He was referencing the Sanskrit Ousruta Sanghita, which also dates from about 2000 B.C.

Tomb Reveals First Clarifying Device
Pictures of the earliest known clarifying apparatus were first excavated from the walls of 15th and 13th century B.C. Egyptian tombs (see illustration on facing page). The device was pictured in the tomb of Amenophis II and later in the tomb of Rameses II. The ancient Egyptian operators allowed impurities to settle out of the liquid, siphoned off the clarified fluid using wick siphons and, finally, stored it for later use.

Bible Refers to Water Quality
The ancient Hebrews were also concerned with clean drinking water. The King James Version of the Holy Bible records examples that date to approximately the ninth century B.C. In Exodus 15:22–27, when Moses and the Israelites came upon Marah, they found that the waters there were bitter. The text states that the Lord showed Moses a tree, and instructed him to cast it into the water. He did so, and the water was sweetened.

While we don’t know exactly what kind of tree Moses used to sweeten the water, later in the 15th chapter of Exodus, the wanderers camp in what might be a desert oasis—which has three wells and is surrounded by palm trees.

Later in the Old Testament—II Kings 2:19– 22—the residents of Jericho confided to Elisha that their city was a pleasant place to live, but the water was “naught.” Elisha went to the city’s springs, where he cast “salt” into water. The waters were thus healed “unto this day.”

Medicine Man Explores Water Treatment
Hippocrates, known as the father of medicine, who lived from 460–354 B.C., wrote the first treatise on public hygiene. In Air, Water, and Places, the medicine man noted that water differed in quality, such as in taste and weight. While his main concern was with finding the most healthful source of water, he did mention how water could be purified.

Using what later became known as “Hippocrates’ sleeve,” which was a cloth bag, he instructed his followers to strain rain water after it had been boiled. Without this treatment, Hippocrates warned that the water would have a bad smell and cause hoarseness.

Other water treatment methods included a drinking cup invented by a ninth century B.C. Spartan lawgiver. The cup was designed to hide badly colored water from its user, causing the mud to stick to its sides. Some of the more credible early water treatment methods included boiling water before transporting it to war zones and filtering it through wick siphons.

The Greeks and Romans are well known for their elaborate water systems. These early water treatment professionals used a variety of methods to control taste and odor problems in their water supplies. For example, Diophanes of the first century B.C. advised putting macerated laurel into rainwater. Later, in the first century A.D., Paxamus proposed that bruised coral or pounded barley, in a bag, be immersed in bad tasting water. The eighth century A.D. Arabian alchemist, Gerber, described various stills for purifying water that used wick siphons—a method that required a fibrous cord that would siphon water from one vessel to another.

Desalination Experiments Begin
In 1627 A Natural History of Ten Centuries was complied by Sir Francis Bacon. This work recorded 10 experiments that dealt with water purification. In it Bacon explained some of his ideas about desalination. He believed that sea water could be purified if it were percolated through sand because he had read that an experimenter had been successful at purifying sea water by passing it through 20 vessels.

Armed with this information, Bacon concluded that “what man could not accomplish, nature might.” He surmised that by digging a hole near the sea shore, water passing through the sand would be naturally purified. Pointing out that the water passed downward through the 20 vessels in the experiment he had read about, Bacon said his seaside experiment would cause it to pass upward. Presumably, salt particles were heavier than water, making it more difficult for them to move in the upward direction, and they would consequently be filtered out by the sand. If only he had been right.

Filtration Is Illustrated
The 17th century A.D. also saw the first known illustration of sand filters. The Italian physician Lucas Antonius Portius wrote the Soldier’s Vade Mecum in 1685, which details a multiple sand filtration method. In this illustration, Portius described three pairs of sand filters—each pair consisting of a downward-flow filter and an upward-flow filter. Water entered the system’s settling compartment through a perforated plate that strained the water.

Once the water had settled, it flowed from the top of the compartment through two funnels and down through the first filter. It then moved out through oblong openings in the bottom of the second filter and up through the second filter. The water continued in this same general pattern through the other two sets of filters.
He also described how pebbles had been
placed near “the funnels of each partition,” and that smaller pebbles and larger sand grains produced the best water. Portius further described his filtration plan as being an imitation of nature’s method of passing water through the “bowels of the earth.”

Every Household Deserves Clean Water
Filtration was becoming the water treatment method of choice for many communities. And town officials began to become concerned with supplying clean water to everyone, wrote Baker and Taras inQuest for Pure Water. Around 1703, the Parisian scientist La Hire presented a plan to the French Academy of Sciences, proposing that every household have a sand filter and rainwater cistern.

His plan included an elevated, covered cistern, which would prevent freezing and keep out light, thus preventing the surface from growing a “greenish kind of moss.” The rainwater should then be passed through river sand and stored underground.

La Hire believed that rainwater treated using this method was the best water because it had not been “mixed with the salt of the earth as spring waters usually are.” And he believed that it could be stored for years, always staying fresh.

Municipal Water Treatment Begins
Approximately 100 years after La Hire proposed his rainwater filtration method, the first municipal water treatment plant was installed in Paisley, Scotland. This 1804 treatment plant consisted of concentric sand and gravel filters, and its distribution system consisted of a horse and cart. Three years later, Glasgow, Scotland, was one of the first cities to pipe filtered water to consumers. By 1827, slow sand filters designed by Robert Thom were put into use at Greenock, Scotland. Similar systems designed by James Simpson were completed in London in 1829. Thom’s filters were cleaned by backwash, while Simpson’s required scraping. The Simpson design eventually became the English model throughout the world.

Throughout 19th century in London, slow sand filtration was the water treatment method of choice. However, the large area of land required to support their use caused some concern. The sand beds, which were two- to three-feet thick, covered acres of ground. Cleaning the beds was usually accomplished using a shovel and vigorous physical effort.

The large area of land required also interfered with land needs for city growth, wrote F.E. Bruce in the History of Technology. For example, the combined water treatment plants of 1849 London treated 44.4 million gallons of water a day. At a flow rate of three gallons per hour per square foot, 12 acres of land would be required to produce the needed water. By 1901, London required 215 million gallons per day of clean water. Obviously, slow sand filters could not keep up with this expanding city.

Because the need for clean water was growing quickly, rapid sand filtration was developed in the U.S. in the 1880s, wrote Baker and Taras. The two main design elements of Thom’s filter were incorporated into this new design—the false bottom and reverse-flow wash—becoming standard features of these filters.

Rapid sand filters used water jets or backwashes to clean the filter media and mechanical agitators to loosen debris. Treatment capacity was greatly increased using these new filters and land area requirements were greatly reduced, noted Baker and Taras. However, rapid sand filtration required pretreatments, such as coagulation and settling, to reduce the sediment load to the filter. Treatment to improve taste and odor of the water was achieved by the use of charcoal filtration, although it was not widely used at first because it was thought to be unfeasible for large supplies.

Links to Health Found
It was also around this time that the first correlation between water quality and health were made, according to the AWWA’s Water Quality Treatment Handbook. In mid-19th century London, town officials noticed a decrease in cholera deaths during the 1849 and 1853 epidemics where slow sand filters had been installed.

But even more convincing evidence emerged when John Snow was able to trace multiple cholera deaths to a single pump in Soho, England, which had become contaminated by a nearby leaking sewer, wrote N.M. Blake in Water for the Cities. An interesting note to this story is that the users of this Broad Street well pump came from other parts of the town because they preferred the taste of the water. This is some of the first evidence that taste and clarity do not always indicate safe water supplies.

Blake wrote that shortly after town officials realized contaminated water had been the culprit in these disease outbreaks, London enacted the Metropolitan Water Act of 1852, which required the filtration of all water supplied to the London area. This legislation is one of the first instances of governmental regulation of a water supply.

New Concerns Emerge
The 19th century also brought the Industrial Revolution, and a whole new perspective on water treatment. Chemicals—and not just microbials—now polluted the world’s water supplies. New, much more sophisticated water treatment methods would now be called for, raising the question, “Once we’ve polluted the water—how do we purify it?”

References
The history of water treatment and waterborne disease will continue in the next edition of On Tap. To learn more about the history of water treatment and waterborne disease, please check the following references:

American Water Works Association (AWWA). 1971.Water Quality and Treatment: A Handbook of Public Water Supply. Denver: AWWA.

Baker, M.N. and Taras, Michael J. 1981. The Quest for Pure Water: The History of the Twentieth Century, Volume 1 and 2. Denver: AWWA.

Blake, Nelson M. 1956. Water for the Cities. Syracuse: Syracuse University Press. Bruce, F.E. 1958. History of Technology, Volume 5. Oxford: Claredon Press.