The Advent and Use of Chlorination to Purify Water in Great Britain and the United States
The Advent and Use of Chlorination to Purify Water in Great Britain and the United States
Of all the conveniences of modern life, the availability of fresh, clean drinking water is perhaps the one taken most for granted. This luxury, however, was only realized around the turn of the twentieth century. In the nineteenth century, the average person in London might find tiny shrimp-like animals or putrid deposits in the drinking water. In Belgium, the water was often yellow and had an unpleasant odor. In 1844, only about 10% of the water from city fountains in Paris was potable. In Germany, the drinking water was brown and foul. In New York, residents complained about paying too much for their impure water. People all around the world were dying of diseases such as cholera and typhoid fever from the filthy water. By the early 1900s, however, this deplorable situation had been rectified. The chlorine industry had been born, and it revolutionized the world's water systems.
Although the modern chlorine industry did not exist before 1900, chlorine's history dates back to 77 a.d., when the Roman scholar Pliny the Elder's (23-79 a.d.) experiments produced hydrogen chloride. The Arabs, about 800 years later, added water to the gas to generate hydrochloric acid. Centuries later, in 1774, Swedish chemist Carl Wilhelm Scheele (1742-1786) was able to make and collect chlorine, and he accidentally discovered its bleaching capability. Five years later, in France, Claude Berthollet (1748-1822) made the first liquid chlorine bleach with potassium hypochlorite; it was called Javelle water, or Eau de Javelle, because it was produced in Javelle, France. In 1810, Sir Humphry Davy (1778-1829) proved that chlorine was an element, naming it after the Greek word khloros, for green.
Wars and revolutions in Europe postponed further advancement of chlorine research for several years. In 1820, French scientists recognized the disinfectant properties of sodium hypochlorite, and seven years later, Thomas Alcock wrote a paper that recommended using chlorites to disinfect hospitals, sewers, and water supplies. In 1894, German chemist Isidor Traube (1860-1943) demonstrated the ability of hypochlorites to disinfect water.
Water supply problems surfaced in the nineteenth century due to rapid industrialization and the concurrent population growth in major cities across Europe and the eastern United States. Suddenly, innumerable factories were in operation, using and polluting water supplies. Additionally, burgeoning cities depended on vastly inadequate sewer systems. Drinking water sources mingled with sewage and industrial waste. Unfortunately, it was not until after 1900 that experts agreed that the germs that caused serious infectious diseases like cholera and typhus flourished in water.
Before the turn of the century, people had often boiled water and then filtered it through substances such as gravel, sand, charcoal, and, later, special carbon filters. The ancient Greeks and Romans knew that boiling their drinking water made it safer. Over the centuries, people also used various metals, such as silver and copper, as disinfectants, but these elements did not consistently reduce bacteria count. Only chlorine proved to be an effective germicide. Consequently, chlorine eventually became the universal choice as a disinfectant.
By the mid-nineteenth century, a few water companies had turned to chlorine to disinfect sewage. In the United States and England, some water supplies were treated with chlorine. In 1888, Professor Albert Leeds obtained the first United States patent for water chlorination; his method combined electrolysis and hydrochloric acid. (Electrolysis refers to the use of an electric current to break up a compound by chemical conversion.) It was thought at the time that the electricity was disinfecting the water, but American William Jewell was convinced that chlorine alone could be a disinfectant agent. In 1896, Jewell used chlorine gas for the first time at a testing station in Kentucky.
Soon, permanent water chlorination plants opened around the world. The first was in 1902 in Middlekerke, Belgium, under the direction of Dr. Maurice Duyk. Polluted water was treated with chloride of lime and then filtered. American and English water experts followed the events in Belgium with enthusiasm, and chlorination soon spread to other countries.
In 1897, in Maidstone, England, Dr. Sims Woodhead had treated the water supply with bleaching powder after a typhoid epidemic there. However, influential men in England still refused to believe that routine chemical treatment of water was necessary to curb disease. An eminent British philosopher even considered compulsory sewage facilities to be an infringement of personal liberties! Finally, scientists were able to convince British medical authorities that chlorine disinfection would indeed curb the spread of serious waterborne diseases. In 1905, the world's second permanent chlorination plant opened in Lincoln, England. There, Dr. Alexander Houston and Dr. McGowan directed an operation that added sodium hypochlorite to water that was then filtered through sand. Eleven years later, the city of London added bleaching powder to the Thames River before its waters flowed into the main aqueduct and were filtered for consumption. Great Britain had at last accepted chlorination as the best way to disinfect its drinking water and sewage waste.
The path to permanent chlorination of water in America began in 1908. At that time, chlorine, in the form of hypochlorites, was used at two separate sites: one was a reservoir in New Jersey, and the other was at the water filters of the stockyards in Chicago. The first American city to install permanent chlorination was Poughkeepsie, New York, in 1909. There, George C. Whipple advised using chloride of lime to treat the water of the Hudson River, after filtration alone did not render the water potable.
Americans gradually turned to liquid chlorine as an alternative to hypochlorites. In 1908, Philadelphia had also decided to use sodium hypochlorite to disinfect its water. Five years later, in 1913, the first permanent liquid chlorination plant was opened in Philadelphia at the city's Belmont filters. Afterwards, chlorination plants spread quickly throughout the industrialized cities on the East coast. Wherever drinking water was chlorinated, typhoid death rates fell by up to 75%. By 1918, more than 1,000 cities in the United States were using chlorine to disinfect their water.
France soon also adopted chlorination methods. The French called the process javellization after the town of Javelle, where liquid chlorine bleach was first made in 1779. Some French cities preferred chlorine gas, while others chose hypochlorite to treat their water supplies. France, along with Britain and America, finally succeeded in obtaining drinking water that was clean, clear, and disease-free.
The role of chlorine as a disinfectant continued to grow throughout the twentieth century. Medical experts learned that the chemical was a powerful weapon that killed both bacteria and viruses by attacking the nucleic acid of bacteria and the protein coat of viruses. Typhus and cholera gradually disappeared as drinking water was chlorinated, vaccinations were developed, and cleanliness standards improved. Nevertheless, the battle to control waterborne diseases continues to the present day. In the overcrowded conditions that arise from wars and natural disasters, especially in third-world countries, people are threatened by outbreaks of cholera and typhus. Wherever and whenever sanitation levels drop, international agencies turn to chlorine to disinfect the water and thus prevent the spread of deadly diseases.
Chlorine has many other uses besides water purification. Of the 15 million tons of chlorine produced in North America alone, only 5% is used to disinfect water. More than 50% of the chlorine produced is used to manufacture other chemicals and plastics, and in products such as anesthetics, perfumes, detergents, paints, and aerospace products. In fact, NASA (National Aeronautics and Space Administration) used chlorine during its Apollo program to disinfect surfaces that might have come in contact with possibly dangerous organisms from space.
It is as a disinfectant, however, that chlorine is most commonly known. Chlorination has the added benefit of being both effective and inexpensive. About one United States dollar will pay for the treatment of one million gallons of water. In emergency situations, six drops of bleach will disinfect a gallon of dirty water in 30 minutes.
In addition to its use in purifying drinking water around the world, chlorine is also used to keep the water in swimming pools clean. Millions of households worldwide choose chlorine products to clean and disinfect their homes. Because sodium hypochlorite is scientifically recognized as perhaps the most effective weapon against dangerous bacteria and viruses, hospitals around the world use chlorine to disinfect instruments and working surfaces, and medical authorities acknowledge that bleach can protect against HIV (Human Immune Deficiency Virus) and Hepatitis B.
Although chlorine has many useful applications, it does have some limitations and drawbacks. For example, chlorine has not proven effective against Legionella, the bacteria that cause Legionnaire's Disease, a serious pneumonia-like infection. And chlorine cannot remove lead or pesticides from water. The most recent worry about chlorinated water is its link to cancer. When it was discovered in the 1990s that chlorinated water could form carcinogenic particles (cancer-causing particles) called THMs, or trihalomethanes, experts began searching for other ways to sterilize water, such as treating the water with ozone, ultraviolet radiation, and iodine. To date, however, these methods are either too complicated or too expensive.
Certain filtration devices can remove traces of chlorine from water. Activated carbon filters, although they do not effectively reduce bacteria, do remove carcinogenic matter. These carbon filters can also be installed below the sink or attached to the faucet. Reverse osmosis is a more expensive filtering system that uses a semipermeable membrane to remove undesirable particles. Many homes use a special filtration device to make their chlorinated drinking water safe.
Aware of the dangers posed by chlorinated water, scientists continue to search for an alternative. A Russian-developed method is an electrolytic water sterilization process that uses electricity to produce certain chemicals that purify the water. Perhaps this method, or another method of water disinfection, such as radiation, iodination, or ozonation, will one day replace chlorination. The only certain thing is that at the beginning of the twenty-first century, man is again facing the same challenge that confronted him 100 years ago: the search for entirely safe and pure drinking water.
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Woodham-Smith, Cecil. Queen Victoria. New York: Alfred Knopf, 1972.
CLEANING UP THE THAMES RIVER
By the mid-nineteenth century, London's Thames River was dangerously polluted by industrial waste and raw sewage. The filthy river water caused thousands to die annually from cholera, typhoid fever, and diphtheria. Summertime was especially miserable because the weather made the river's odor worse, and insects swarmed everywhere. Some members of Parliament actually fainted during the summer from the Thames' awful smell. The royal family also suffered. The windows of Buckingham Palace were kept closed because of the horrid stench and the flies. The drains of Windsor Castle were labeled "...more dangerous than a tropical jungle" by one biographer (Cecil Woodham-Smith, Queen Victoria, 1972, p. 430). Prince Albert, Queen Victoria's husband, had campaigned tirelessly but to no avail to have the Thames cleaned up. It is indeed ironic but not surprising that the Prince's untimely death in 1861 was attributed to typhoid fever. A few months after he died, the clean-up effort began. Fifteen years later, there was a sewage system in operation that allowed waste material to enter the Thames downstream of London.