Types of Water Filtration
There are many ways that the water flowing through our homes gets filtered before it arrives. These types of filtration can be done at your local water treatment plant or from a water filtration system you have installed in your house. Below, Advanced Water Solutions will discuss the different types of common water filtration and give you a brief look at how it’s filtered before flowing through your faucets.
Distillation is one of the oldest methods of water purification. The first step to distillation is heating the water to boiling. The water vapor then rises up to a condenser, where the lower temperature cools the water. This allows the vapor to be condensed, collected, and stored in another container. When this process is complete, most of the contaminants are left behind in the original liquid phase vessel.
However, sometimes carryovers can be found in distilled water. Some organics cannot be removed efficiently and can become concentrated in the product water, leaving it acidic. The distilled water can lack oxygen and minerals as well, leaving you with a flat taste. This is why distillation is mostly used in industrial processes rather than for plain drinking water. The other disadvantage to this process is cost, as it requires larger amounts of energy and is relatively slow to produce large amounts of clean water.
With this type of water filtration, ions are exchanged for other ions. An ion is a positively or negatively charged particle. The two most common ion-exchange methods are softening and deionization.
A water softener usually replaces calcium and magnesium ions from the water with sodium ions contained in filtration beads. The softening of water is used mostly as a pretreatment to help reduce the water hardness prior to other filtration methods. It’s also used in the home to create more palatable water that’s easier to use for cleaning. Check out AWS’s blog on hard vs soft water here for more information.
In deionization, the beads exchange either hydrogen ions (consisting of single hydrogen atoms) or hydroxyl ions (negatively charged units containing an oxygen atom and a hydrogen atom). This process swaps out a hydrogen ion for any cations (positively charged particles) they encounter. The hydrogen ion from the cation exchanger unites with the hydroxyl ion to form pure water (H + OH = H2O).
Carbon absorption is most widely used in home water filter treatment. This is because of its ability to improve the water by removing unsavory tastes and odors. It uses highly porous activated carbon to effectively remove many chemicals and gases. However, only a few carbon filter systems have been certified for the removal of lead, asbestos, and coliform, so do your research if you need to remove such harmful substances.
There are two types of carbon filter systems: granular activated carbon and solid block carbon. The use of a carbon filtration system is usually combined with other treatment processes, such as reverse osmosis. The placement of carbon in relation to any other filtration components is important when you consider the design of a water purification system, since you don’t want to be left with extra carbon in your drinking water.
Reverse osmosis is the most economical method for removing 90 to 99 percent of all contaminants. Reverse osmosis technology is used by most water bottling plants. Natural osmosis occurs when solutions with two different concentrations are separated by a semi-permeable membrane. Osmotic pressure then drives the water through the membrane so that the water dilutes the more concentrated solution.
To use this is method in water filtration systems, hydraulic pressure is applied to the solution to counteract the osmotic pressure. The pure water is driven out from the concentrated solution and collected separately. If you’re interested in learning more about how reverse osmosis works, check out AWS’s blog here.
Water Purification Systems
With each water filtration system working in a different way, you can’t always rely on just one method to remove all the contaminants to the levels required to make it safe. If you’re using a well-designed water purification system, it’s most likely using a combination of technologies to achieve the best water quality before it gets to you.
Each technology has a job to do and must be used in the correct sequence to gain the best removal capabilities. Creating the correct combination of water filtration systems and setting up proper pretreatment will help produce water that is almost completely free of ionic, organic, and microbial contamination and tastes and smells great.
Your local water treatment plant has most of this in place for you, so you can rest assured that you are getting some great water coming from your faucets. However, if you want to take that extra step to ensure the most purified water possible for your home, you can look into getting a whole home water filtration system or water softener.