Although manganese occurs naturally in groundwater across the globe, it can present a challenge, especially when its concentrations exceed 0.05 mg/L.
Excessive manganese gives water an unpleasant brownish color, makes it unsafe to drink, and clogs plumbing parts. It’s, therefore, necessary to find suitable water treatment options.
In this article, we discuss everything you need to know about manganese and the various ways of removing it from water.
Table of Contents
- 1 What Is Manganese?
- 2 Is Manganese All Bad?
- 3 Manganese In Drinking Water
- 4 Evidence of Manganese In Your Home
- 5 So, How Does Manganese Get Into Water?
- 6 What Are the Health Risks Associated with Manganese?
- 7 What’s the Safe Threshold of Manganese in Drinking Water?
- 8 How to Test for Manganese in Drinking Water
- 9 How to Remove Manganese from Water
- 10 Frequently Asked Questions (FAQs)
- 11 Conclusion
What Is Manganese?
Manganese is a naturally occurring earth metal. It could appear in its pure elemental form, but it predominantly occurs in combined forms with other substances in more than 100 minerals. It can also appear in various foods such as grains, nuts, legumes, milk, fruits, and vegetables.
Is Manganese All Bad?
Manganese is not all bad. It’s an essential micronutrient in the human body that plays a crucial role in the normal functioning of enzymes, specific body metabolisms, bone formation, reproduction, and immune response.
Manganese In Drinking Water
There are two ways manganese can occur in water – dissolved manganese and solid (precipitate form) manganese. What’s more, manganese can be found both in city water and well water. In water from certain deep wells, the concentration may hit a level of 3 parts per million (PPM).
However, the big question is: when does it become toxic? As you’re probably aware, excessive levels of this trace element can be harmful to human health, besides ruining the aesthetics of home appliances.
Several countries have set the concentration standard for manganese to roughly 0.05 mg/L, yet even as little as 0.02 mg/L can form ugly coatings on water pipes or black sediments in water.
Beyond 0.05 mg/L, manganese gives residential water a peculiar black, orange or brown tinge. At certain elevated concentrations, drinking water may even assume a horrible metallic smell.
Evidence of Manganese In Your Home
Manganese commonly occurs together with iron. Together, they form the two leading causes of deep brown stains and other damages to home appliances. You can see evidence of manganese in water as deposits on your laundry, water-based appliances, and sink surfaces.
You may also notice this on the surface of toilet water in the form of a brownish coat. In the dishwasher, you may find signs of a black precipitate. That’s because many dishwashing detergents raise the pH of water. As such, it readily reacts with the manganese causing it to solidify out.
Extreme levels of precipitate manifest through blockage of plumbing and reduced water pressure from faucets and showerheads.
So, How Does Manganese Get Into Water?
Manganese is abundant in surface water. For this reason, it easily ends up in wells as a result of surface runoff. Surface runoff and rainwater may also combine to pick up manganese as they seep through soils and rocks containing it. Manganese-containing water may then finally rest in underground water sources such as wells.
Human activity is another key contributing factor in adding manganese to the sources of drinking water. In certain mining setups, iron and manganese could occur in more significant quantities in the soil and get ferried to water sources through surface runoff. Traffic emissions may also be directly linked with high manganese content in the air and the ground.
As highlighted before, iron and manganese are often present at the same time in the water. The pair are common in groundwater, although manganese will often occur in relatively lower concentrations. This implies that if your water supply can be tested and proven to contain iron, then it’s highly likely it would have manganese as well.
At very high manganese concentrations, you might notice a strange bitter taste from your water and beverages. At that point, your physical health is at risk.
What Are the Health Risks Associated with Manganese?
While manganese is an essential nutrient in the human diet, consuming too much of it is dangerous.
However, don’t worry about consuming excess manganese in food as there’s insufficient evidence to back any possible toxicity from dietary intake of manganese.
This leaves only one other potential source: drinking water.
Individuals who have consumed drinking water with elevated levels of manganese (beyond 0.05 PPM) have demonstrated manganese toxicity and terrible health complications.
Prolonged exposure to manganese in water can lead to various nervous system diseases, with symptoms such as Parkinson’s disease, insomnia, depression, irritability, tremors, and hearing loss.
Children and infants are placed at a far worse risk since excessive manganese can take a toll on their cognitive abilities, and they may develop problems with learning and behavior.
What’s the Safe Threshold of Manganese in Drinking Water?
City water could be considered safe to some extent. But for residents with private wells, regular tests and checks are recommended.
The threshold of 0.05 mg/L is detrimental to tap water quality, yet the safe level of manganese in drinking water is almost or slightly over six times as much. Specific standards clearly define that a person shouldn’t be exposed to over 0.3 mg/L of manganese in drinking water throughout their life.
Babies and children under three years of age should never drink any water with manganese levels exceeding this limit, especially when formula constitutes their diet. In America, the Environmental Protection Agency has clearly outlined this.
But how can you test for the presence of this metal in drinking water?
Let’s take a look.
How to Test for Manganese in Drinking Water
Bearing in mind all the dangers of excessive manganese consumption, it’s easy to understand the significance of testing drinking water.
You can figure out what your water contains and to what degree, ultimately determining whether or not it’s safe for consumption using the best lab testing kits and DIY kits.
If you’re interested in only the best testing out there, you need to enlist the services of a certified laboratory. You’ll simply need to collect samples from your home and send them off to the laboratory in approved testing kits.
Since manganese occurs either in dissolved form or in precipitate form, an accredited laboratory should thoroughly advise on the ideal water treatment systems to eliminate this impurity.
Keep in mind with a lot of the DIY test kits, your test data may not be 100% accurate. Rather, they’ll only indicate the general presence of manganese without indicating exact proportions.
While this is useful, sometimes it’s best to stick with the pros.
This is why it’s best to choose one of the Professional Lab order kits if you want the most accurate data.
How to Remove Manganese from Water
The pH of water, the presence of other minerals, and other factors make the removal of manganese a somewhat daunting task.
Luckily for you, there are countless simple yet effective methods for overcoming these challenges. Let’s take a quick look at each:
a) Air Injection Filtration (Aeration)
This type of filtration system effectively eliminates high levels of dissolved metals and is also tough on hydrogen sulfide ions. Furthermore, it’s relatively pocket-friendly as the filtering resin isn’t even required. Here’s how it works:
Water is fed into a tank, after which a fresh pocket of air is injected at the top. The dissolved metals will become oxidized, essentially changing state. Upon sticking on the media bed, you can easily remove them.
During regeneration, the tank is fed with a fresh air supply. At face value, this may sound like a drawback, but it isn’t. Accumulation of more manganese and other metals in the water implies regular maintenance like regeneration. It’s a boost for efficiency.
We list some of the top AIF well water filters here.
b) Ion Exchange
Water softening via ion exchange is a highly effective and popular means of removing hardness minerals like magnesium and calcium. The good news is that whole home water softeners can also remove manganese and iron. The basic principle is that hardness minerals are attracted to a resin bed which gives off sodium ions to replace them.
Based on this, sodium ions could still be released into the water to displace manganese, which then sticks on the resin bed. Such water softeners need to backwash their tanks from time to time when the media capacity hits the upper limit.
The media is repeatedly flushed out and taken over by sodium ions, giving way to a fresh cycle. Most water softeners meant to reduce hardness are efficient if manganese concentration is in the lows of 3-20 GPG.
The best water softeners remove manganese and are worth the price tag if your water meets the following conditions:
- It should contain low dissolved oxygen concentrations
- Its pH should be above the optimum level of 6.5.
- Iron concentrations should fall below 5 mg/L.
Tips and Tricks
- Very high iron and manganese levels in their oxidized states are more harmful to a water softener resin.
- Some water softeners aren’t as effective in removing manganese.
- Do not expose raw water to strong oxidizers like chlorine before passing into the water softener to avoid destroying the softener resin. Furthermore, filtration more effectively removes residues of manganese and iron in raw water.
- We recommend regular backwashing of softener resins, say once a week.
c) Oxidation Media
Oxidation filtration solutions are generally suited to cases where iron and manganese levels range within 2-10 mg/L. Manganese-based filter media remove the metal itself through catalytic oxidation.
These include anthracite coal and manganese greensand. The latter is more prevalent in the design of filter media and is made specifically for iron, manganese, and hydrogen sulfide removal.
In manganese greensand filter systems, potassium permanganate oxidizes iron and manganese. The two are then trapped in the filter bed and flushed out. Regular maintenance through regeneration of the oxidation filtration media and system backwashing is necessary. The higher the concentration of metals in drinking water, the more frequent backwashing is required.
Birm is another trusted brand when it comes to efficient and economical granular filtration. It’s an excellent option for removing dissolved iron and manganese. The Birm filter works well with water whose pH is no less than 7.5 and has plenty of dissolved oxygen.
Its key upside is that no regeneration is required (only backwashing is needed). The filtration media used in Birm derive oxygen from the water itself to oxidize iron ad manganese.
d) Reverse Osmosis
This is the ultimate water treatment process that removes virtually all impurities. State-of-the-art reverse osmosis systems employ several filtration stages, including semi-permeable membranes, activated carbon filter cartridge membranes, sediment filter cartridge membranes, and post-filter membranes.
All in all, reverse osmosis membranes feature very tiny pores which sieve out impurities and bacteria, allowing only fine water particles through. Contaminants are flushed out with wastewater, and not even the smallest dissolved impurities and bacteria can escape.
While you don’t need to worry about backwash when it comes to reverse osmosis systems, the filter membranes need changing once every 6-12 months. Likewise, semi-permeable membranes need replacement roughly every two years.
Frequently Asked Questions (FAQs)
Does Chemical Treatment Do Away with Manganese?
Short answer: yes. Strong oxidizers like chlorine work pretty similar to the air injection chamber, which uses air enriched with oxygen. A contact time of around 20 minutes is sufficient to thoroughly oxidize water by added chlorine.
Does Catalytic Carbon Remove Manganese?
Sure. This method removes manganese efficiently and checks or totally removes various agents of contamination, including excessive chlorine. However, the process proves more effective following oxidation.
Does Boiling Water Help With Removing Manganese?
Not at all. Boiling water for too long will only evaporate most of it. In the end, you’ll end up with even higher concentrations of crystallized minerals and precipitates, including manganese.
The best way to get rid of contaminants like manganese is to use the best filtration systems and softening systems such as the ones we’ve thus discussed.
Despite having some nutritional benefits in small quantities, manganese can become toxic in large amounts. It’s therefore essential to find ways to remove excess manganese from your drinking water.
Fortunately, there are several effective techniques for purifying water containing excessive manganese, including aeration, reverse osmosis, oxidation media, and ion exchange.