Does Reverse Osmosis Remove Manganese?

Reverse osmosis systems are highly effective at reducing a whole host of common drinking water contaminants – but is manganese one of them?

Can you rely on an RO system to remove manganese? And how much manganese can reverse osmosis remove?

Find out the answers to these questions in this guide.

🤔 Does A Reverse Osmosis System Remove Manganese?

Yes, a reverse osmosis system can remove manganese from your drinking water supply.

RO systems use a purification process that reduces up to 99.99% of total dissolved solids. Manganese is a dissolved mineral, which means it’s one of the contaminants that can be reduced by RO.

However, just because a reverse osmosis system can remove manganese molecules, it doesn’t mean that it’s the best solution for treating manganese-contaminated water.

📊 How Much Manganese Can An RO System Remove?

When used to treat water with low levels of manganese, a reverse osmosis system can remove up to 99% of this mineral.

That means the purified water that leaves the RO system should be virtually manganese-free.

The exact amount of manganese removed from an RO water filter depends on factors including:

• The concentration of manganese present – The more manganese in the water, the higher the likelihood that some of the minerals will be retained.
• The age of the membrane – Old membranes may be worn or damaged, making them less effective at removing all contaminants, including manganese.
• The membrane quality – The better the membrane quality, the more contaminants it should be able to remove.
• The other contaminants present – Certain other minerals and impurities may affect the membrane’s ability to reduce manganese.

🔎 How Does Reverse Osmosis Reduce Manganese?

A reverse osmosis uses several filter stages, including a sediment pre-filter, and an activated carbon pre-filter and post-filter. But the filter stage that reduces manganese is the semi-permeable membrane.

Water is forced through the RO system at a high pressure. When it reaches the membrane, the membrane’s tiny pores (around 0.0001 microns) block the majority of dissolved contaminants, including manganese, from passing through.

These contaminants rebound into the RO chamber and are flushed down a drain. The water particles are small enough to pass through the pores.

The water that leaves the RO membrane has been thoroughly separated from its impurities and is almost completely free from minerals (including dissolved manganese), chemicals, and microorganisms.

🧐 Should You Use A Reverse Osmosis System For Manganese Removal?

You can use a reverse osmosis system to effectively remove manganese in water supplies with low concentrations of this dissolved mineral.

However, if your water contains more than 2 PPM of manganese, we don’t recommend using an RO filter to remove this contaminant because excess manganese will foul and damage the membrane.

Another thing to consider is the typical RO system design and use point.

Chances are, if you have iron and manganese in your water, you want a whole-home solution to remove these minerals from your entire home’s water supply.

While whole-home RO systems are available, they’re very expensive – usually $4,000+. You can buy a highly capable whole-home manganese removal filter for one-third of this price.

📋 Effects Of Manganese On The RO Membrane

If your drinking water contains manganese, you’ve probably noticed the effects of this mineral already.

Manganese leaves dark brown or black stains on fixtures and appliances, including your toilet bowl and your sink plug.

It does the same thing to the membrane inside an RO system, building up on the membrane’s surface and clogging the pores.

Over time, this will restrict water flow through the membrane. If there are fewer pores in the membrane for water to travel through, a larger volume of water will end up getting flushed away with the contaminants during the RO process, reducing the system’s efficiency.

Plus, manganese is almost always present alongside iron, and moderate-to-high iron concentrations will also foul the membrane and reduce its efficiency and purification performance.

🚰 Alternatives To Reverse Osmosis For Reducing Manganese

If your water has a high manganese or dissolved iron concentration, we recommend looking at a dedicated filtration system that can handle these minerals with minimum fouling or media damage.

Let’s take a look at the best alternatives to reverse osmosis for reducing manganese.

Oxidation Filters

Oxidation and filtration systems are the best all-in-one solution for reducing both types of manganese (manganous manganese and manganic manganese), along with iron and hydrogen sulfide.

You can find this system in various forms, all designed for whole-home installation:

• Chemical injection systems, which use a chemical feed pump to inject chemicals (like ozone, potassium permanganate, or hydrogen peroxide) into the water, oxidizing the manganese and other dissolved metals. This oxidized manganese is then trapped in a filter media (such as an activated carbon filter bed).
• Air injection systems, which use dissolved oxygen to oxidize the manganese, then remove the solid particles with a filter media (like birm).
• Media-only systems, which use a filter media that’s capable of oxidizing and removing manganese in one, such as a manganese greensand filter.

Air injection systems and manganese greensand filters are a great solution if you don’t want to add anything to your water to remove manganese. However, if you have very high levels of manganese, it’s worth considering a chemical injection system using a strong oxidizer like a potassium permanganate solution, which will offer the best manganese reduction results.

Regardless of the system you choose, it should be able to reduce at least 4-5 PPM of manganese, eliminating water staining and the bitter metallic taste of this mineral.

Water Softeners

If your water has low manganese levels and you want to remove these from your whole home’s plumbing system, consider installing a water softener.

The primary purpose of a water softener is to remove hardness minerals with ion exchange. However, this ion exchange process can also remove low levels of manganese and iron.

Just as the calcium and magnesium hardness ions are exchanged with sodium ions, manganese ions can be exchanged too. These are then flushed out of the softener resin bed when the system regenerates.

Don’t use a water softener for manganese reduction if you have more than 2-3 PPM of manganese in your water because this may foul the water softener resin.

📑 Final Word

The good news is that manganese doesn’t pose a human health risk at low levels – so much so that the Environmental Protection Agency (EPA) doesn’t deem it worthy of a legal regulation in drinking water.

However, a high manganese concentration can result in unpleasant stains on your fixtures – not to mention that manganese and iron give water a bitter and metallic taste that may put you off drinking it.

Luckily, there are several water treatment solutions to tackle manganese contamination, depending on the amount of manganese in your tap water.

RO systems are a good option if your manganese levels are low, but for the best results, we recommend a dedicated whole-home manganese and iron removal system.