Two parts hydrogen and one part oxygen—these three tiny particles make up one of the most vital pieces of our human existence. And while hydrogen and oxygen form water at its most molecular state, hundreds of invaders find their way into our water sources every day. “Cleaning up” water and making it safe to ingest is an extremely important task in making sure that we have potable water we need to survive.
Without clean drinking water, we risk disease and even death. Thankfully, humans have learned and developed processes to create safe water from even the poorest of sources. Filtration and purification are two processes that help sustain healthy water sources. Clean drinking water is a vitally important issue and understanding the processes needed to make it safe helps ensure you continue to drink and cook with safe, clean water.
Filtration Versus Purification
You may see bottled waters sold in stores labeled as “pure” or “purified.” You may even have a water filter on your kitchen faucet or in your refrigerator. So what are the differences between filtration and purification?
On the simplest of levels, filtration is the process that removes solid particles from a liquid or gas. Water filtration removes fine solid particles such as sand, grit and dirt from the liquid making it smooth and particle-free.
Used in conjunction with filtering, purification is also a process used to clean a water source. While filtration removes small physical particles from the water, purification works on a more molecular level.
Purification removes harmful bacteria, chemicals or other biological contaminants from a water source. Filtration is often used as a part of the purification process although purification is the most important step for creating safe, clean, potable water.
How Does Filtration Work?
As explained previously, water filtration is the process of removing particulates from water, including grit, sand, dirt and other solid particles. The most powerful filtration systems can remove particles as small as bacteria. Filtration makes water appear cleaner, although does not necessarily make water safer since it doesn’t remove things like viruses or other contaminants.
Filtration uses a physical barrier, chemical process or biological process to remove the impurities from a water source. The process allows the good stuff, in this case the water, to pass through the filter while the bad stuff—dirt, sand, sediment, pollutants—gets filtered from the water.
One popular method of filtering water is carbon filtering. Carbon filtering uses activated carbon to filter sediment and impurities. Activated carbon filters water through a process called adsorption. Adsorption causes small molecules and various pollutants in the water to become trapped inside the pores of the carbon. Carbon is most effective when used to remove sediment, chlorine and volatile organic compounds (VOCs) from water. Carbon filters also remove poor odors and taste from water although it cannot adequately remove particles such as minerals and salts.
Carbon filters are often used as household water filters and the technology has even been translated to work for camping, survival and emergency kits. In small form, carbon filters can be purchased and packed into outdoor gear as well as emergency survival kits. When used in conjunction with water purification, filtration systems create potable water in nearly any situation.
How Does Purification Work?
Like filtration, water purification is a process used to remove undesirable particles and contaminants from water. Purification typically takes filtration a step further, and often uses filtration methods as part of the purification process in an attempt to ensure the water is safe for consumption. Water purification removes various biological contaminants, including chemicals, gases, and solids, that cause severe harm when ingested by humans. Purification does not necessarily make water appear cleaner or clearer and it does create safe, potable drinking water.
Water purification is a multi-step process that typically envelopes several smaller processes, including filtration. Depending on the type of impurities found in the water, various techniques may be employed to help purify a water source.
- Disinfection is often needed to treat polluted water.
- Chlorine is often used to disinfect water.
- Chlorine, or in some cases iodine, shocks the water source and can clear the water of dangerous micro-organisms. There is a fine balance needed when using chlorine or iodine to disinfect and purify water. Both chemicals have to be used in exact measurements and can be tricky, as too much of either can be harmful if ingested.
- UV light treatment is another option for disinfecting water and is generally considered a safer option as there are no harmful chemicals used in the process and disinfection occurs immediately.
Reverse osmosis is one of the most recognizable options in water purification. Osmosis happens when water is diffused across a semi-permeable membrane from an area of low solute concentration to an area of high solute concentration. Reverse osmosis is the opposite of this process. Reverse osmosis occurs when water is forced across a membrane from a highly-concentrated area to a low-concentrated area. As the high pressure forces the water through the membrane, the membrane works to catch and trap the undesirable contaminants in the water. The reverse osmosis portion of water purification is considered to be one of the most effective pieces of the water purification process, as it traps and removes most micro-particles in the water source.
Reverse osmosis is highly efficient at removing particles from water sources. It is a popular choice to remove salt, iron and other minerals from water. It is often used in conjunction with filtering processes such as carbon filtration to completely and properly create potable drinking water. While filtering manages to remove much of the sediment and larger particles found in water sources, purification can remove dangerous organisms such as bacteria and viruses and is what ultimately creates safe, potable drinking water.
Why is clean water so important?
Lack of access to clean water is one of the world’s largest problems and environmental water contamination is one of the world’s biggest killers. According to the World Health Organization (WHO), diarrheal diseases affect nearly 1.7 billion people a year, killing approximately 760,000 children under the age of five each year. The lack of safe water drinking sources around the world significantly contributes to diarrheal diseases. While the United States and other developed nations have managed to create potable drinking water on a large scale, many countries and their citizens are still without access to clean water.
On a smaller scale, access to potable water is a concern in emergency or survival situations. In the wake of a natural disaster or in a wilderness survival situation, water sources may be compromised or even non-existent. Tools to filter and purify water are often found in portable packs and units designed to fit in backpacks and survival kits. Having a basic knowledge about water purification and filtration principles is key to understanding, and ultimately creating, a safe source of water even when using a prepackaged unit.