Coagulation is one of the most important parts of the water treatment process. It is primarily used by water treatment facilities, but some water filtration systems also use a form of coagulation that can make the system’s filters more effective. Today we’re going to discuss exactly what coagulation is and how it works, the positives and negatives of this process and also what options you have for purifying and treating the water in your home.
The Coagulation Process
Coagulation is the first step in the water purification process used by most municipal water treatment plants. Coagulation is an ion-exchange process that works by adding a positively charged chemical known as a coagulant to the water. Most plants use aluminum sulfate or alum, which is a type of aluminum salt, but the process can also be done using several different iron salts instead.
Before the water is treated, it contains a large amount of suspended contaminants such as silt, sand and clay as well as bacteria and numerous minerals. All these contaminants are negatively charged. When the positively charged coagulant is added to the water, it neutralizes all the contaminants and causes them to stick to the coagulant ions. This results in a process known as flocculation, which is when the suspended particles clump together and form larger, heavier particles known as flocs. This process is essential, as all the contaminants can’t be effectively filtered out if they remain suspended in the water.
The next steps in the process are sedimentation and filtration. Sedimentation involves letting the water sit for a time so that all the flocs settle down to the bottom and the clean water remains on top. The water is then pumped through a series of filters, which remove any smaller pieces of sediment remaining in the water. Once the water has been filtered, the last step is to disinfect it with chlorine or chloramine to kill any bacteria, parasites or viruses that may still remain.
How Coagulation and Disinfection Can Affect Your Drinking Water
Coagulation is extremely effective at removing suspended contaminants from water, which is why it is used by most water treatment facilities. When done properly, the process should be completely safe. The only issue is that a small amount of aluminum or whatever other coagulant chemical was used can sometimes remain in the water after it has been treated.
Aluminum is generally safe at low levels. However, it is still classed as a non-essential metal, which means that it has the potential to harm your health. All water treatment facilities are required to test to ensure that the amount of aluminum in the water doesn’t exceed a certain level. Nonetheless, there is still a huge amount that we don’t know about the specific effects of even low concentrations of aluminum on the human body. Many studies have linked high levels of aluminum in the body to an increased risk of neurodegenerative disorders such as Alzheimer’s disease and Parkinson’s disease. Although the World Health Organization (WHO) states that the amount of aluminum normally found in drinking water typically doesn’t have any toxic effects, they also advise against dismissing the strong link between aluminum in drinking water and Alzheimer’s.
Another issue with municipal water treatment is that drinking water often contains chlorine, which can also cause serious health issues at high levels. The good news is that the U.S. Environmental Protection Agency (EPA) requires all water treatment facilities to regularly test to ensure that the amount of chlorine in the water is at a safe level. However, even safe levels can give drinking water a strong chlorine taste and smell.
The chlorine in water has also been proven to contribute to poor indoor air quality. According to the EPA, U.S. homes and businesses have a somewhat high level of chloroform gas in the air. This is because any time you use your sink or take a shower, some of the chlorine in the water vaporizes and sends chloroform gas into the air. The same process also occurs every time you flush the toilet.
How Water Filtration Systems Can Remove Aluminum, Chlorine and Other Contaminants
If you’re concerned about aluminum and other contaminant in your water or want to ensure that your drinking water doesn’t smell and taste of chlorine, then you should definitely consider investing in a water filtration system. Any water filtration system with an activated carbon filter will work to remove chlorine so that your water tastes and smells better.
Both water filtration systems and reverse osmosis systems can also be extremely effective at removing aluminum from your water. These systems will also remove virtually all other contaminants such as lead, iron and bacteria. Even though drinking water should be clean and pure when it leaves the water treatment plant, it often picks up silt, sand, bacteria and other contaminants as it makes its way through the municipal water treatment system to your home or place of business. One of the biggest issues is caused by corrosion of old pipes, which can lead to a variety of metals leaching out into the water.
With a water filtration system or a reverse osmosis system, this is something you’ll no longer need to be concerned about. You can rely on the system to filter out any metals, sediment and other contaminants. You can better protect your health since you can be assured that your water is completely clean, free of odors and much better tasting.
Depending on your specific water quality issues, you can also opt for a system that includes some type of pretreatment before the water is filtered. Many of these pretreatment systems also use a coagulant to cause any suspended particles to clump together. This type of pretreatment can be especially useful because it can make the actual filtration system far more effective. The reason is that if the contaminants remain suspended in the water and don’t clump together into larger particles, they may be small enough that they can still pass through the filter.
The difference between this type of pretreatment and the coagulation process used by water treatment plants is that most pretreatment systems use some type of organic coagulant. As such, you don’t need to worry about the system adding aluminum or other potentially harmful chemicals to your drinking water.
How the Ion-Exchange Process Works in a Water Softener
Most water softeners also use an ion-exchange process to remove suspended calcium and magnesium and prevent hard water issues, and this process works almost exactly like coagulation. A water softener tank is filled with thousands of small, positively-charged resin beads. As with other contaminants, the dissolved calcium and magnesium ions in your water are negatively charged. Oppositely charged ions always attract and stick to one another. As a result, the calcium and magnesium ions stick to the resin beads and are fully removed before the water flows out of the softener tank and into your plumbing system.
The water softener tank is then occasionally backflushed with a brine solution, which causes the resin beads to let go of the calcium and magnesium. The tank is then flushed with fresh water so that the brine and all the minerals are washed out of the tank and into your sewage system.
Expert Water Treatment Services
At Wyman Plumbing & Mechanical, we’re your No. 1 choice for water treatment in the Phoenix, AZ area. We specialize in a range of residential and commercial water treatment services. Our team installs and services water filtration systems, reverse osmosis systems and water softeners. To learn more about our water treatment services or to schedule any other plumbing, drain or sewer services, contact us today.
