What Is A Water Filter?
A water filter is a device used to remove impurities from tap or bottled water. There are many types of filters available. Some are designed to remove bacteria while others are meant to kill viruses and protozoa (such as Giardia). Most filters will treat both pathogens and microorganisms but some only handle one type of contaminant. Filters come in different sizes depending on how much they need to be cleaned before use.
Types Of Water Purification System:
There are two main types of water filtration systems: reverse osmosis and ultraviolet (UV) disinfection. Reverse osmosis filters out all solids such as minerals, salts, organic matter and other materials.
UV disinfection kills harmful microorganisms by absorbing sunlight energy which then causes chemical reactions that destroy them.
Reverse Osmosis vs. UV Disinfection:
The primary difference between reverse osmosis and ultraviolet disinfection is that UV disinfection uses ultraviolet light to break down the compounds found in water. These chemicals include heavy metals, pesticides, pharmaceuticals and other substances that may cause health problems if ingested or inhaled.
While reverse osmosis removes these contaminants through a physical process, it does not eliminate them completely because some are still present in the water after treatment.
Reverse osmosis (RO) is a process that forces water through a semi-permeable membrane that only allows pure water to pass through. THe first step in this process, called pre-treatment involves adding a sodium solution to the water.
The second step involves forcing the water through the membrane at high pressure. Any contaminants in the water cannot pass through the membrane and remain on the non-permeable side. The third and final step of the process is removing any remaining sodium from the water by passing it through an “ion exchanger” that binds with all the sodium, which can then be removed from the water.
Produces the highest amount of pure water with less waste water.
More consistent than even reverse osmosis alone.
Does not require as much energy as reverse osmosis alone.
Most expensive of all the available methods.
Water waste can be up to four times that of the standard faucet.
Does not remove microorganisms, only inorganic materials
UV disinfection also uses inorganic materials but kills them with ultraviolet light instead of straining them out. This process involves three main steps: pre-treatment, mixing and exposure.
The pre-treatment step uses a coagulant, typically aluminum sulfate, to make solids in the water clump together. These solids are then collected by a filter before moving on to the mixing step. In this step, ozone is injected into the water. Since ozone is a gas, it will quickly rise to the surface of the container and begin undergoing a chemical reaction. The ozone oxidizes any microorganisms in the water, killing them. The final step is to expose the water to high-intensity UV light. This step helps to inactivate any organic materials that may have survived the ozone treatment.
Relatively inexpensive and does not waste water.
Does not remove as many inorganic materials as other filters.
Cannot remove all microorganisms.
Ion Exchange (IEX or R.O.):
Ion exchange is a process that uses a resin to bind with magnesium and calcium ions, which are then removed from the water and exchanged for hydrogen ions. This process leaves behind water with a very low mineral content, which many people prefer over tap water with high levels of minerals.
In some cases, this water may be “too clean,” as it will lack beneficial minerals.
Removes many minerals from water
Very consistent process
Does not remove microorganisms
Slightly more expensive than other methods
Unlike reverse osmosis or IEX, activated alumina works by binding with minerals such as calcium and magnesium instead of forcing them through a semi-permeable membrane. This process uses pressure to push water through a very porous material filled with alumina, which attracts the desired minerals while rejecting other materials.
Does not waste water
Inexpensive and can be installed in any home
Can remove up to 97% of dissolved solids from water
Doesn’t always remove all microorganisms
Can leave behind a fine white powder on some water
Distillation works by boiling water and then re-condensing the steam into pure water. The main part of this process is the container, which must be airtight.
Boiling the water forces the steam to rise and then pass into a separate container—often a tube whose open end is submerged in cooling water. The steam then condenses back into liquid form. This liquid (now water) can be collected separately from the container. The steam is then released back into the main container once it has cooled.
Relatively cheap to provide water for large groups of people
Doesn’t use any chemicals or filters, so the process is very eco-friendly
Very slow and requires a lot of energy to constantly boil the water
Slightly more expensive and complicated to install for individual families
In order to use this method, your area needs to be relatively warm
Solar Water Disinfection (SODIS):
Solar water disinfection is a process that uses the sun’s energy to make contaminated water safe. It is regarded as the safest and most affordable method of providing clean drinking water in developing countries.
All you need is a clear plastic bottle, which can be purchased cheaply in bulk.
Relatively cheap and easy to implement
Doesn’t require any expensive equipment or installation
Can be used in areas with or without direct sunlight
Does not remove inorganic chemicals
Does not kill viruses, so the water is not safe to drink without filtering
The Bottom Line
Water filtration and purification systems can be an expensive addition to your emergency supplies. However, clean water is important for your health and an important part of your preparedness strategy.
If you want clean water in the worst way, it might be worthwhile to invest in a system that fits your needs.
Sources & references used in this article:
Laccase grafted membranes for advanced water filtration systems: a green approach to water purification technology by J Singh, V Saharan, S Kumar, P Gulati… – Critical Reviews in …, 2018 – Taylor & Francis
Rain and storm water filtration systems by SE Esmond, L Quinn, RK Weir – US Patent 6,705,049, 2004 – Google Patents
Surface water filtration systems by G Kent – US Patent 9,051,192, 2015 – Google Patents
Acceptance and Impact of Point‐of‐Use Water Filtration Systems in Rural Guatemala by KL Larson, C Hansen, M Ritz… – Journal of Nursing …, 2017 – Wiley Online Library
Portable water filtration system and method by CW Palmer, MR Palmer – US Patent 5,914,045, 1999 – Google Patents
Water filtration and erosion control system by D Hastings – US Patent 7,449,105, 2008 – Google Patents
Portable water filtration bottle by CW Palmer, MR Palmer – US Patent 6,004,460, 1999 – Google Patents