In 2016 Cindy Hu, a data scientist from the Havard University, was involved in research that found out that about six million Americans consumed water with PFAS above the EPA recommended level.
PFAs, which is a short form for polyfluoroalkyl and perfluoroalkyl, are artificial chemicals. They are found in many daily routine areas, including fast-food wrappers, in the blood, household items, and tap water.
There are more than 4000 of these chemicals. They are resistant to moisture, stains, and heat. These chemicals result from combining the carbon and fluorine elements, making a powerful bond. The elements have long lives making their effects on humans last longer.
In water, the chemicals are common in the water treatment facilities; thereby, they find their way to the tap water.
PFAS in drinking water have adverse effects on the human body, and that’s why you need to filter your water to remove them.
This piece will explain how to filter PFAs from drinking water.
Let’s get started
Ways to Remove PFAS in Drinking Water
There are several ways that the environmental protection agency has approved to remove the PFAS from your water.
1. Granular Activated Carbon
This type of filter is filled with organic raw materials such as coconut shells and coal. These components work to remove PFOA and PFOs chemicals present in your tap water.
Once the water passes through the granular activated carbon, the PFAS chemicals in your water are trapped and removed through adsorption.
When using this method to filter the PFAs, you need to know in advance your amount of water consumption. This will guide you on the quantity of the activated carbon content you will need for the filtration exercise.
These systems require accurate installation and frequent maintenance to serve you for a long while. The rate at which the activated carbon in this system is consumed depends on the amount of PFAS chemicals in your water and your water demand.
With time the GAC requires changing once it’s unable to bind and remove the high levels of PFAS in your water.
The GAC filtration procedure works efficiently on longer PFAS such as the PFOA and PFOS. Some granular activated carbon filters can last several years with proper maintenance.
Mainly there are two types of GAC filters.
- Whole-house water filters
- Point of use filters
Whole House Filters
This type of GAC filter is placed at the point of entry of the main water supply line for your home.
With this filter, all the water used throughout your home is treated, and the PFOA and PFOS in your water are eliminated. The system removes the chemicals before they are ingested into your plumbing system.
Most of these filters come in two or more cylinders to ensure the chemicals that may have escaped in the first cylinder are trapped in the second one.
Once the first cylinder is used up, the second one replaces it as the filter is replaced. This ensures that your home is supplied with clean water at all times. Between the cylinders are ports that allow you to test the water.
Point of Use Filter
This type of GAC filter is placed near the faucet, close to where people access their drinking water.
A GAC pitcher commonly sold in grocery stores and the under sink filters are examples of point-of-use GAC filters.
Both types work effectively in removing PFOA and PFOS. However, timely replacement of the filters prevents bacterial build-up and boosts their effectiveness. When buying the filters, check to ensure that they are certified by relevant bodies such as the NSF.
In determining the type of filter to use, consider the following factors:
- Chemicals present in your water
- Water use
- Type and quantity of impurities in your water
2. Ion Exchange Resins
These are small beads that comprise hydrocarbon ions that work like magnets. To remove the PFOA and PFOS, the chemicals stick to the beads as water flows.
For the resins to perform optimally, check to ensure that they are made of extremely porous material insoluble in water. Mostly those made of polymeric material work best.
Ion exchange resins are broadly classified under two categories, the cationic and the anionic ions.
The negatively charged cationic exchange resins are responsible for removing the positively charged anion impurities. On the other hand, the positively charged anion resins effectively remove negatively charged contaminants, especially the PFAS.
More people prefer the anion exchange resins to remove the PFAS chemicals as they don’t regenerate; thus, there’s no need to worry about treating or disposing of the waste stream.
It’s worth noting that the anion exchange resins’ functionality will depend on the choice of resins, other contaminants, your water flow rate, and the bed depth.
The type of PFAS you intend to get rid of also determines the effectiveness of the exchange resins.
3. Powdered Activated Carbon(PAC)
With the PAC, all you need to do is add the activated carbon to your tap water, and the PFOA and PFOS stick to it, allowing only the water molecules to remain.
The PAC uses the same principle as granular activated carbon. The only difference is that these are smaller in size and powder form. This means that the PAC will not work well where you need to run water through. They work better on still water where you add directly.
After adding, you can now remove the particles through ultrafiltration. However, the PAC can only work well on low water volumes, where the PFAS are not at very high levels.
The GAC is more efficient and economical for high water volumes with high PFAs and a run-through bed. You will also incur another cost with PAC on disposing and cleaning the sludge that remains behind after adsorption.
The powdered activated carbon can not work effectively in a commercial setting where a running water bed is needed, and water is needed in plenty.
4. Reverse Osmosis
Under this water treatment procedure, the water is pushed through a reverse osmosis membrane with very tiny pores of about 0.0001 microns.
To remove PFAS through this system, your tap water is pushed against the semi-permeable membrane, which works to prevent the PFAS chemicals from flowing through.
A reverse osmosis filtration procedure has several purification processes that the water passes through before hitting the membrane. This makes the high-pressure membrane highly effective in removing PFAS.
The reverse osmosis system works well in removing PFAS chemicals both long and short and is known to remove more than 95% of the PFOA and PFOS.
However, under this system, about 20% of the water is retained as highly contaminated. This makes the system suitable for a point of use, such as a home setting. This is because homeowners use lower volumes of water; thus, the waste is equally low.
This filtration procedure uses the same principles as reverse osmosis.
The main difference between the two is that the membrane under nanofiltration can operate under low pressure and eliminate specific contaminants based on size and charge.
The nanofiltration membrane has bigger pores that allow the water molecules to pass through and the salts to pass through.
This process is effective in removing PFAS chemicals as well soften your hard water. Additionally, nanofiltration purifiers waste less water.
It’s worth noting that NF filters work better in removing the longer PFAS compared to shorter ones. However, reverse osmosis does a better job of getting rid of all types of chemicals than other methods.
For all the above methods, regular and prompt maintenance is required for optimal performance. Replacement of resin, filters, and membranes requires proper scheduling throughout the year for optimal performance.
Not all types of filters will get rid of the PFAS in your water, so it’s important as you are buying to clarify from the packaging, the manual, or the manufacturer.
Some distillers in the market have claimed over 90% success rate in getting rid of PFAS.
The distillation process, which involves the heating and cooling of water, can eliminate the short form of PFAS. However, for long PFAS, you must combine the process with the other methods mentioned earlier to work better.
The process takes longer, and it’s not cost-effective. The impurities evaporate, and water molecules are retained; however, further purification would yield a 98% success rate.
You can use this method for your home setting, where the pure water demand is minimal.
Factors to Consider When Choosing the Right Method for Filtering PFAS From Drinking Water
Different locations across the US have different types and levels of PFAS. Check out with the center for disease control whether your location is listed as prone to PFAS.
However, even if your location is not on the list, it doesn’t mean you are not at risk of the PFAS. Homes located next to water sources such as rivers, manufacturing facilities, airports, and military bases are also at risk of PFAS.
2. Type of PFAS
With over 4000 different types of PFAS, some are long while others are short. Some methods, such as nanofiltration, work more effectively for the longer PFAS.
3. Water Demand
The amount of water needed for your home use will determine the filtration method you can use to remove the PFAS in your drinking water. A reverse osmosis system can handle large volumes of water, while an on-point filter is best suited for low volumes.
4. Other Contaminants
The number of contaminants in your water will determine the method you use for your filtration process. The presence of other contaminants in your water will affect the method you use. An increased level of different impurities reverse osmosis will serve you best.
The different methods differ in cost. The initial cost for a reverse osmosis system is more expensive, and also, the maintenance cost of replacing the filters can be costly.
Compared to the ion exchange resin, the GAC is less costly and can last longer where the water demand is not high.
6. Space Available
Some of the procedures mentioned above involve systems that take up a lot of space. For instance, reverse osmosis involves several filtration processes. The more the stages, the more space the system will take up.
Furthermore, it would be best to establish whether your plumbing system has the space to accommodate the systems at the point of entry. Check whether you need to do any modifications before you buy to avoid any disappointments during installation.
Why You Need to Filter PFAS From Your Drinking
The presence of PFAS in your drinking water should not be taken lightly, as they have adverse health effects on your overall health.
The following are justifications for why you need to filter them out. PFAS:
- Increases the chances of asthmatic attacks
- Raise your cholesterol levels
- It affects how your body responds to vaccines.
- Decrease the fertility rate
- Boost the risk of contracting cancer
- Lower the weight of newborns
- Increase the risk of hypertension in pregnant women.
Though there is no clarity on the right levels of PFAS content in the tap water, the EPA gave an advisory of 70 parts per trillion in an individual’s lifetime.
Through water treatment, you can avoid these adverse effects by ensuring you only consume pure water. Replace the water filters on time and ensure they are certified by the relevant standardization bodies.
Getting rid of PFAS in your drinking water will save your household from adverse health effects. Consider investing in a purification system that not only removes PFAS from your water but can also eliminate other contaminants.
Some of the market filter brands will soften your water, filter, and get rid of the PFAS.
As you embark on removing the chemicals, consider how you will handle the waste treatment once the water regenerates or flows down the drain. The contaminated water could contain higher levels of PFAS that could cause environmental harm.
When choosing the right method for eliminating the PFAS, consider your available space, PFAS found in your location, and your pure water demands.
Take note that boiling water doesn’t get rid of PFAS chemicals.
After installation, frequently test for PFAS to establish whether the purification process is functional.