Purifying Polluted Water: Effective Filtration Techniques Explored

Water filtration is an essential process, especially in the wake of rising water pollution levels. There are several methods to purify polluted water by filtration, including boiling, chemical treatments, and UV filtration. Boiling is a cheap and effective way to purify water, as the high temperature kills most bacteria and microorganisms. However, it is important to note that boiling water does not remove physical debris, and it is not suitable for water contaminated with physical materials. Chemical treatments, such as iodine, chlorine, and disinfectant tablets, can also be used to purify water by removing harmful organisms. Another method is UV filtration, which uses ultraviolet light to deactivate microorganisms, making the water safe for consumption. These filtration methods are crucial for ensuring access to clean and safe drinking water, especially in remote or natural environments.

Characteristics and Values of Water Purification by Filtration

Boiling water

To purify water through boiling, one must first filter the water through a clean cloth, paper towel, or coffee filter if the water is cloudy. This step is important as cloudy water can block UV light, preventing purification. Once the water is clear, bring it to a rolling boil and leave it to boil for at least one minute. The World Health Organization (WHO) recommends boiling water for three minutes if you are at an altitude above 5,000 feet (1,000 meters) or 6,500 feet, according to another source. The high temperature and duration of boiling are crucial to effectively kill the organisms in the water.

After boiling, remove the water from the heat source and let it cool down naturally. Do not add ice to the water. Instead, you can improve the flat taste of boiled water by adding a pinch of salt to each quart or liter of water. Once cooled, store the purified water in a clean container with a cover to prevent re-contamination.

While boiling is an effective method to kill pathogens, it does not remove chemical contaminants, heavy metals, salts, or other toxins. Therefore, it is often recommended to combine boiling with other purification methods, such as filtration, to ensure comprehensive purification. For example, one can use a high-quality water filter to remove contaminants like chlorine, lead, and bacteria before boiling the water to kill any remaining pathogens.

Using purification tablets

Water purification tablets are a convenient method for filtering water, especially for those on the go. They are easy to use, portable, and can be used in conjunction with other water purification methods for optimal results.

There are several types of water purification tablets available, each with its own advantages and disadvantages. Chlorine dioxide tablets, for example, are widely available and effective at killing bacteria, viruses, and parasites. However, they may leave an unpleasant taste in the mouth. Chlorine and silver-based tablets are another option, which can be purchased from chemists and travel shops. These tablets are useful for destroying most bacteria but are less effective against viruses and cysts. Combining them with products containing phosphoric acid, such as Aquamira®, can enhance their effectiveness.

Iodine tablets are another type of water purification tablet. While they used to be a standard in backpacking kits, they have fallen out of favour due to their unpleasant taste and potential health concerns when consumed in large quantities over extended periods. However, they can still be useful in emergency kits that are not regularly refreshed.

When choosing water purification tablets, it is essential to consider factors such as shelf life, taste, ease of use, and effectiveness against bacteria, protozoa, and viruses. Price is also an important consideration, especially for longer trips, as some tablets can be individually wrapped, leading to more waste and higher costs.

For those seeking a simple and quick solution, Aquatabs® are a popular option. These tablets are easy to use and provide safe drinking water within 30 minutes. They are widely used globally, providing access to clean water for communities in need.

UV treatment

Water purification is essential to ensure that water is safe for drinking and other uses. While filtration is an effective method to purify water, it does not eliminate all microorganisms and contaminants. This is where UV treatment, also known as ultraviolet disinfection, comes into play.

The UV-C light used in UV sterilizers is powerful enough to disinfect drinking water. However, it is important to avoid direct contact with the bulb and not to look directly at it while it is in use. With proper use, UV-C light poses no harm to humans and is a much safer alternative to other forms of water treatment.

Overall, UV treatment is a reliable and safe method to purify water, especially when paired with filtration systems. It provides clean and safe drinking water with minimal maintenance and is an excellent option for residential and commercial use.

Chlorine purification

The process of chlorine purification was first discovered in Sweden in 1744. Initially, chlorine was used to eliminate odours from water, but it wasn't until 1890 that it was recognised as an effective disinfectant for water. The first practical demonstration of municipal water purification using chlorine was in 1910 by Major Carl Rogers Darnall, and it has been a standard method of disinfection since.

Chlorine can be added to water in liquid or gaseous form, with the specific method depending on the scale of purification. For large-scale water treatment plants, gaseous chlorine is typically used, while liquid sodium hypochlorite (bleach) or chlorine tablets are more suitable for smaller-scale purification. When using chlorine tablets, they should be dissolved in heated water, ideally at 21°C or higher. Chlorine can also be added to water in the form of calcium hypochlorite, which was first used by Major William J. L. Lyster of the Army Medical Department.

Filtering with sand and charcoal

To create a DIY charcoal and sand water filter, you will need a few simple tools and materials. Firstly, source a cylindrical container, such as a bucket or a two-litre soda bottle with one end cut off. You will also need a large stone, grass or sand, and fresh charcoal that has been completely cooled. The charcoal can be sourced from a campfire or grill. It is important to ensure that the charcoal is fresh and completely cooled to maximise its effectiveness in the filtration process.

Once you have gathered your materials, you can begin constructing your filter. Start by creating a funnel that will act as the filter. You can use a large leaf or a strip of tree bark to craft the funnel. If you are using a soda bottle, cut the top off and invert it so that the bottle cap is pointing towards the bottom. This will serve as your funnel.

Now, you can assemble the layers of your filter. Start by pouring pebbles into the bottle, followed by a layer of coarse sand, and then a layer of fine sand. The sand layer plays a crucial role in catching smaller particles, such as dirt and grit, giving the water a clean appearance.

The final layer is the charcoal. This step is essential as it eliminates bacteria and some chemicals from the water. Activated charcoal, in particular, is highly effective due to its ability to absorb toxins, drugs, viruses, bacteria, and some harmful chemicals. It is important to note that boiling the water after filtration is still recommended to ensure the complete removal of bacteria and viruses.

Frequently asked questions