Purifying Polluted Water: Home-Based Methods For Clean Drinking

Water purification is essential to ensure that contaminated water is safe for consumption. There are various methods to purify water at home, including boiling, chlorination, filtration, distillation, and reverse osmosis. Boiling water is a traditional and effective way to kill microorganisms and make water safe to drink, but it does not remove heavy metals and dissolved solids. Chlorination is a chemical process that kills germs, parasites, and other disease-causing organisms, but it should be used with caution. Filtration is a simple and cost-effective method that removes dangerous compounds and contaminants, including heavy metals. Distillation uses heat to collect pure water vapour, leaving behind sediments and contaminants with higher boiling points. Reverse osmosis is a modern physical purification method that removes dissolved salts, impurities, and germs. These techniques are crucial for ensuring access to safe drinking water, especially in areas with limited resources or inadequate sanitation.

Characteristics and Values of Home Water Purification Methods

Boiling water

To boil water, simply heat it until it reaches its boiling point, and maintain it at that temperature for at least one minute. For those living in high-altitude areas, it is recommended to boil water for longer than water boiled at lower altitudes, as water boils at lower temperatures at higher altitudes.

After boiling the water, it should be covered and left to cool before drinking. Dead microorganisms and impurities may settle at the bottom of the water, so to remove these, the water should be strained through a microporous sieve.

Chlorination

The process of chlorination was first formally proposed in a paper published in 1894, which suggested adding chlorine to water to make it "germ-free". Two other authorities endorsed this proposal and published it in many other papers in 1895. Early attempts at implementing water chlorination at a water treatment plant were made in 1893 in Hamburg, Germany. In 1897, the town of Maidstone, England, became the first to have its entire water supply treated with chlorine.

Chlorine is a powerful chemical that kills germs, parasites, and other disease-causing organisms found in ground or tap water. It is also effective in preventing the growth of algae at treatment plants, which can cause taste and odor problems. Chlorine can be added to water in the form of tablets or liquid. When using chlorine tablets, it is important to apply them to heated water, as they dissolve well in water that is at 21°C or higher.

Distillation

To begin the distillation process, water is heated until it reaches its boiling point. It is then left to boil until it vaporises. This vapour is then directed into a condenser, where it cools and turns back into liquid water. This water is now clean and safe to drink. Any substances with a higher boiling point are left behind as sediment in the container.

It is worth noting that boiling water is the cheapest and safest method of water purification. It is a time-tested method that has been used for centuries to make water safe for consumption. Boiling water kills heat-sensitive pathogens like bacteria, viruses, and protozoa, and destroys the cell walls of these pathogens, rendering them inactive and unable to cause illness. However, boiling water does not remove heavy metals and other dissolved solids, so further purification methods may be necessary.

Filtration

Water filtration is a simple, cost-effective, and commonly used method to purify water at home. It is a physical process that can effectively remove both large and small dangerous compounds, contaminants, and impurities that may aggregate inside water, which are known to cause waterborne diseases.

The first experiments into water filtration were made in the 17th century by Sir Francis Bacon, who attempted to desalinate seawater by passing it through a sand filter. Although his experiment did not succeed, it marked the beginning of a new interest in the field. The first documented use of sand filters to purify the water supply dates to 1804, when John Gibb, the owner of a bleachery in Paisley, Scotland, installed an experimental filter and sold his surplus to the public.

Today, there are two main types of water filtration: traditional and modern. Traditional water filtration methods include sand filters, which are the most common type of filter to purify water. Water passes through the sand, which usually has a layer of activated carbon (or anthracite coal) directly above it. The activated carbon filters out organic compounds and improves the taste and odor of the water. However, rapid sand filters without additional carbon filters are ineffective against taste and odor. Many household water filters and fish tanks use activated carbon filters to purify water.

Modern water filtration methods include electric reverse osmosis (RO) purifiers that contain UV (ultraviolet) and UF (ultra-filtration) filters. These are the most trusted method used in houses today. The RO membrane has fine pores that trap germs and dissolved chemicals, allowing only purified water to pass through. The UV filtration process involves passing water through a chamber where it is exposed to ultraviolet light, which deactivates microorganisms. The UF purification process uses a membrane similar to RO but with bigger pores, effectively removing physical impurities, including pathogenic organisms and turbidity.

Reverse osmosis

The reverse osmosis process involves forcing water across a semipermeable membrane to remove ions, unwanted molecules, and other harmful contaminants from drinking water. The membrane allows pure water to pass through while filtering out particles like salts, minerals, metals, and most bacteria and viruses. This is achieved by using your home's water pressure to push tap water through the membrane, with water, being a smaller molecule, forced through tiny holes while dissolved inorganic solids are rejected and flushed away.

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