Per- and polyfluroalkyl substances (PFAS) are contaminants in Arizona drinking water. They commonly come from firefighting foams. But PFAS can also get into the water supply from cleaning supplies, nonstick cookware, and personal care products.
PFAS removal is incredibly difficult with conventional water treatments. But does reverse osmosis remove PFAS? Reverse osmosis is one of the top ways to remove harmful chemicals including many PFAS from drinking water.
Homeowners can purchase reverse osmosis (RO) filters for whole-home use. These solutions can be pricey. The good news is that there are more affordable options for homeowners on a budget.
Just how effective are RO house systems for removing PFAS? We will explore the answer to this question below. Keep reading to learn more or use the following table of contents to skip to the information most important to you.
PFAS filtration systems work by removing many PFAS from drinking water at the point of entry. RO filters remove PFAS contaminants using semi-permeable reverse osmosis membranes. These membranes consist of cellulose acetate or polysulfone, a type of thermoplastic.
We call them semi-permeable because membranes contain microscopic holes. Water molecules are small enough to get through the holes, but PFAS and other pollutants are not. As water passes through the membrane, it filters out these larger substances.
The holes or pores in RO filters measure around 0.0005 microns. The majority of PFAS are much, much larger, making RO membranes extremely effective for removing most of these contaminants. Another reason is the addition of activated carbon, which we’ll dive into below!
A granular activated carbon filter or ion exchange resin system may also work well against common water pollutants. But they work even better in combination with RO filters.
Some RO systems don't use multiple filters, but the best ones do. High-quality RO systems incorporate activated carbon filters which effectively reduce PFAS contaminants.
These filters contain pieces of carbon. Similar to semi-permeable membranes, the carbon features small holes or pores. The pores capture PFAS and other pollutants as they pass through, while leaving the water supply unharmed.
Activated carbon filters are so effective because of the way carbon responds to chemicals. Carbon reacts with PFAS and other substances in a way that causes chemicals to stick to the carbon.
The Environmental Protection Agency reports that RO filters remove over 90% of PFAS in drinking supplies. Activated carbon filters can be even more effective. Some filter out up to 100% of PFAS in water.
However, studies have debated these older findings. A recent Duke University study concluded that RO systems are more effective than any other type of filtration system, including activated carbon systems. Unfortunately, the study did not test RO against filtration systems that combine the two.
The exact percentage of PFAS these filters can remove depends on the type. Some RO filters are more permeable than others. For example, cellulose acetate membranes struggle with smaller and high-weight chemicals.
Another consideration is the filter's durability, membranes made of cellulose acetate can break down in extreme pH environments. This compromises the membrane's effectiveness against PFAS.
At the same time, cellulose acetate filters can handle chlorinated water. Compare that to polysulfone membranes, which will not work as well when exposed to chlorine.
A final consideration for effectiveness is the volume of water passing through the system. The higher the water volume is, the less effective the system may be. Luckily, most homes get a higher degree of filtration because they need to use water than commercial properties.
Phoenix is one of six cities with the hardest water supplies in the world. These cities average 18 grams per gallon of drinking water, which is nearly five times the amount of minerals and salts in soft water.
The most common minerals found in Arizona water supplies are calcium and magnesium. These minerals may be good for your health in moderation. But hard water can also wreak havoc on your home appliances, skin, and hair.
Luckily, RO filters are effective at removing all minerals and salts found in hard water. In addition to PFASs, calcium, and magnesium, high-quality reverse osmosis filters will take care of:
Ions and metals like arsenic, aluminum, chloride, copper, iron, lead, mercury, nitrate, radium, sulfate, and zinc
Particles like asbestos
Pesticides like endrin, heptachlor, and lindane
Radionuclides like radium and uranium
It is possible for RO systems to remove bacteria and other microorganisms from drinking supplies. However, most manufacturers don't recommend their filters for that use because semi-permeable membranes can break down and become less effective in these conditions.
RO systems remove far more contaminants than they leave behind. Still, it is important to understand which pollutants you shouldn't expect your RO filter to work against. To date, no known treatments can filter out all water pollutants.
For example, filters can't remove dissolved gases from water. That's bad news for people with a rotten egg smell in their water. This smell comes from dissolved hydrogen sulfide gas.
Other substances reverse osmosis can't handle include certain pesticides and VOCs. VOC stands for volatile organic compound. The good news is carbon filters can get rid of many of the chemicals RO filters can't remove.
So, does reverse osmosis remove PFAS? Yes, RO filters are the most effective way to eliminate most of these contaminants from your drinking water. They work even better when combined with activated-carbon filters.
If you are searching for the most effective home filtration system, EcoWater Systems is top of the list. This system utilizes three different filters, including an RO filter and activated carbon.
Get in touch with Parker & Sons in Phoenix to request a quote. Our technicians can help you find the best system for your home, whether it's EcoWater Systems or a comparable solution.