Does Reverse Osmosis Remove Aluminum from Water? Let’s Find Out!
Written by: Gene Fitzgerald // Last Updated: Apr 27, 2023
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Aluminum in drinking water has become even more common in recent times. So, how to get rid of it?
Well, reverse osmosis is among the most recognized water filtration technologies today.
But just how effective is it? And can it help you remove aluminum from your home water supply? Let’s find out!
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Key Takeaways
- Reverse osmosis removes about 98% of aluminum from water.
Does Reverse Osmosis Remove Aluminum from Water?
So, does reverse osmosis remove aluminum from water?
Yes, reverse osmosis removes aluminum from water. In fact, it can be trusted to remove 98% of aluminum which, obviously, is almost all the aluminum in your water.
How Does Reverse Osmosis Remove Aluminum?
Reverse osmosis is the #1 recommended method for removing aluminum in water. But to understand how reverse osmosis removes aluminum, you’d need to know how the process works in the first place.
Reverse osmosis purifies water by sending it through a semipermeable membrane under high pressure. The pores on the RO membrane are very tiny (0.0001 microns), so only water molecules can pass through them. Contaminants like aluminum are rejected, so they’re stuck on the membrane and do not proceed into the clean water reservoir.
So while the filtered water is stored away in a storage tank, the contaminants on the membrane are flushed down the drain in a separate stream – referred to as waste water.
That’s why reverse osmosis wastes water in its operations, and many people see this as the biggest downside. Luckily, there are ways to reduce the waste water produced, like introducing a booster or permeate pump.
Other Ways to Remove Aluminum from Water
Although highly effective, reverse osmosis is not the only way to get rid of aluminum. Other ways to remove aluminum from water include distillation and cation exchange.
Distillation
Distillation works based on the principle of different boiling points. During distillation, the distiller heats water until it reaches its boiling point of 212 °F (100 °C). The water turns to steam and rises into the condensing chamber, where it condenses into liquid and is collected as purified water.
Aluminum has a much higher boiling point than water (4478 °F), so it’s left behind in the boiling chamber and does move out with the water molecules. This method effectively separates water from any aluminum. The major drawback of this process is that it’s expensive and time-consuming.
Cation Exchange
Cation exchange, on the other hand, works by replacing aluminum ions in water with other positively charged ions. With cation exchange, water is pushed over the charged resin bed, and aluminum is deposited on the resin and is exchanged for ions like calcium and sodium.
The salt bed has to be flushed occasionally to prevent aluminum from building up and overwhelming it.
Although cation exchange can remove aluminum from water effectively, it’s not very practical for usage at home. The reason for this is that in the case of aluminum, the salt bed must be regenerated with chemicals like sulfuric or hydrochloric acid. These chemicals can be hazardous if not handled correctly. You’ll also need special equipment to carry out the procedure. It’s too much of a hassle to implement at home.
What Is Aluminum and How Does It Enter Our Water Supplies?
Aluminum is the third most common element on Earth, making up about 8% of the Earth’s surface. It’s a silvery-white metal..
Aluminum is used to create things like cooking utensils, building materials, containers, ceramics, paints, and glass. It also exists in different forms for different products like antacids (aluminum hydroxide), deodorants (aluminum chlorohydrate), and water treatment chemicals (aluminum sulfate).
With such widespread use in our environment, it’s easy to see how aluminum can get into our water supply. Two ways are water treatment and leaching. Let’s talk about them.
Water Treatment
In some cases, aluminum is intentionally added to water during municipal water treatment. It’s added in the form of aluminum sulfate, which treats water by coagulating small contaminant particles. When the contaminants are coagulated or clumped together, they form much bigger particles that can easily be filtered off through mechanical filtration.
When done properly, coagulation leaves a very small amount of residual aluminum in the water. It’s mostly used to attack contaminants unaffected by traditional disinfection methods like chlorination. Aluminum coagulation attacks microbes like E. coli, cryptosporidium, and giardia, which are typically resistant to chlorination.
Leaching
As we mentioned, aluminum is abundant in our environment. It’s not surprising that it easily leaches into our water sources.
Aluminum can enter your water supply by leaching into ground and surface waters. There are several ways this can play out.
- For example, aluminum-rich waste from incinerators and coal-fired plants can pollute groundwater with aluminum.
- Aluminum is also commonly used to make many things we use every day, like cooking utensils, cosmetics, and food additives. When these goods are left to deteriorate in landfills, they accumulate waste that leaches aluminum into the groundwater supply.
- Not all leaching is our fault, though. Aluminum could leach into groundwater from rocks and soil containing natural aluminum, or from surface water containing aluminum dust.
Aluminum Water Bottles
The concept of aluminum water bottles may bother you, but there’s usually nothing to worry about. As long as the content of your bottle has a pH range of 4-10, you should not experience any leaching. Some things to avoid with your aluminum water bottle include:
- Colas and highly acidic juices
- Dishwashers (they usually use highly alkaline detergents, which can cause leaching)
You should also avoid aluminum water bottles lined with epoxy/bisphenol-A (BPA). These bottles leach BPA into the water, and BPA can be harmful to your health.
How Can I Test for Aluminum in My Drinking Water?
Usually, you can’t tell that your water has aluminum just by looking at or smelling it. But if aluminum is present at levels above 0.2 ppm, your water may take on a hazy or bluish color.
Unlike other contaminants, there are no home test kits to detect the presence of aluminum. The only way to know your water has aluminum is by testing it at an EPA-certified lab. Lab tests provide in-depth analysis, telling you the contaminants in your water and the percentage in which they exist.
Alternatively, you could request a water quality report from your water provider. The EPA makes it mandatory for municipalities to monitor water for contaminants and make the reports accessible to the public. You can contact your local water company and request information on your water’s quality for free. All you need to do is read through the report and note what it says about aluminum in your water.
If you use a private well, no annual water quality reports are available for you. Your only option is to test your water at a lab. Although it’s not free, it’s definitely worth it. You can check the EPA website to find the EPA-certified lab closest to you.
Further Reading:
Health Effects: Is Aluminum in Drinking Water Harmful?
Aluminum in drinking water is unlikely to harm your health at low doses. However, high concentrations of aluminum have been seen to affect parts of the human brain and the nervous system, causing neurodegenerative diseases like Alzheimer’s disease, Parkinson’s disease, and Lou Gehrig’s disease (ALS).
There’s also speculation that aluminum might cause skeletal problems.
Good news is, there’s currently no evidence to suggest that aluminum causes cancer or affects reproduction.
How Much Aluminum Is Safe in Drinking Water?
It’s tricky to say how much aluminum is “safe” in drinking water. According to the EPA, aluminum’s secondary maximum contaminant level (SMCL) is 0.05–0.2 mg/L. Beyond this range, water starts to look, taste, and smell funny.
Note: The EPA’s SMCL range for aluminum is not health-based (it does not imply that water is safe or unsafe within that range). The EPA set that standard solely to control water aesthetics.
Regulations
There are currently no EPA regulations that determine the safety of water with aluminum. Even though the EPA has set a secondary maximum contaminant level of 0.05–0.2 mg/L, the guidelines are considered “non-mandatory” as they only serve to prevent weird tastes, colors, and smells in the water.
The FDA also set a limit for aluminum in water at 0.2 ppm. This is also purely for aesthetic reasons and not a health-focused guideline.
If you have any thoughts about the question, does reverse osmosis remove aluminum, please don’t hesitate to leave a comment below!
About the Author Gene Fitzgerald
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