Impure water is a water that contaminated by unwanted elements. It can be particles, colloids, debris. Of course, for both drinking water or clean water for household activities, these impurities are not wanted. Thus, it is important for us to treat source water to remove these elements. That is why we need water treatment.
The effect of impure water was found in Susruta Samhita, back to 2000 BCA, which recommended that water be boiled before drinking. In case you are wondering about Susruta Samhita, it was one of India’s ancient book of knowledge, which is the foundation of the Indian system of natural healing. At that time, people tend to measure water feasible for drinking by tasting it, people still could not distinguish between foul and clean water. Turbidity was the main trigger between the earlies water treatment back then.
After 1500 BC, the Egyptians first discovered the principle of coagulation. They employed chemical alum to settle suspended solid. 500 BC forward, it was Hippocrates whose discovered the healing powers of water. He invented the first bag filter, popular with name “Hippocratic sleeve”. The implementation was to trap sediments that caused bad odors and tastes. Next, as mentioned in previous post, water supply and wastewater system brief history,in 300-200 BC, acient Rome built its first water channel construction, popular with the name aqueducts.
During the Middle Ages (500-1500 AD), there were lack of lack of scientific innovations and experiments, also known as the Dark Ages. Aqueducts were destroyed by Roman Empire’s enemy. In 1627, Sir Francis Bacon started experimenting seawater desalination to remove salt particles. Altough it was not succesful, it gained appreciation by scientists followed.
In 1676, Van Leeuwenhoek first observed water microorganisms by employing grinded and polished lenses to get significant magnification for tiny particles in water. First water filters for domestic application were installed, made of wool, sponge and charcoal. Afterwards, there were other installation were build. A notable failure was the New Orleans system for
filtering water from the Mississippi River. The water proved to be so muddy that the filters clogged too fast, this made the machine would not work. This problem was not alleviated until aluminum sulfate (alum) began to be used as a pretreatment to filtration. The use of alum to clarify water was proposed in 1757, but was not convincingly demonstrated
Municipal water treatment plant was first built in Parsley, Scotland, including the use of water filtration in 1804. It was based on slow sand filtration, and horse and cart distributed the water. Approximately three years later, first water pipes were installed.
The crucial development of water treatment occured in 1854, when there was cholera epidemic spread through water in London. Interestingly, the outbreak was less in areas where sand filters were utilised. John Snow found that the cause was water pump contamination by sewage water, so he used chlorine to purify the water. This paved the way for water disinfection. The water in the pumped was normal tasted and smelled, thus it drives the conclusion that good taste and smell alone will not guarantee safe drinking water. This founding led to installation of municipal water treatment consisted of sand filters and chlorination, and first government regulation of public water.
In 1890s America started building sand filters for public health protection. Rapid filtration was also applied, together with water chlorination as well. However, after negative effects of chloride were discovered, water experts started looking for alternatives, such as hypo chloride and ferric chloride, mixed and used in Belgium. Ozone was applied in 1906 in France.
Starting 1914, eventually drinking water standards were established and implemented for water supplies, based on coliform growth. In 1972, the Clean Water Act was passed in United States, and two years later, the Safe Drinking Water Act (SDWA) was formulated. The very general principle was people have rights and deserve for clean and safe water.