Manganese is a metal in air, soil, food, and drinking water. It is also commonly found in well water worldwide. Rainwater washes manganese into drinking water, and surface water seeps into the ground.
Manganese does not harm human health in small amounts. However, several studies have shown that too much dosage can pose a health risk.
Indeed, the manganese in the water can be a nuisance. It produces a metallic aftertaste on the water. It stains the clothes. It clogs the valve and produces a crusty sheen on the water's surface.
Due to the stains, bad taste, and general nuisance of manganese in the water, the federal government created a standard. It was discussed in the Safe Drinking Water Act of 1974.
There is good news. Various water treatment options can enable the water to become safe for drinking. As such, you don’t have to drink contaminated water.
Thus, this article introduces ways to remove manganese from the water. Also, this would tackle the drinking water standards and the authorities' initiatives to protect its citizens.
What is Manganese?
Manganese (Mn) is a natural element in the air, soil, and water. It is an essential nutrient for humans and animals. Yet, deficiency or overexposure to manganese can have adverse health effects.
The main exposure of manganese to humans is from food ingestion because manganese activates many cellular enzymes and others.
Although it is an essential nutrient at low dosage, chronic exposure to high dosage may be harmful.
Some data show that inhalation of manganese may affect both humans and animals.
On the one hand, little data show the toxic effects of manganese through oral exposure.
The Environmental Protection Agency (EPA) provided communities with health advisories.
This advisory guides the concentration to avoid health and organoleptic problems.
The EPA analyzed the current health hazards and organoleptic information for Mn-contaminated water.
Manganese Uses
Manganese has many industrial uses. It is used to make iron and steel alloys and compounds and is an ingredient in various products.
Manganese and other compounds are also found in batteries, glass, varnish, various cleaning supplies, fertilizers, fungicides, cosmetics, and livestock-feeding supplements.
Manganese greensands are useful in some locations for potable water treatment. Like Canada, other manganese. In Canada, other manganese compounds enhance the octane of unleaded petrol.
Sources of Manganese
Manganese makes up 0.1% of the earth’s crust, making it one of the most abundant metals on the earth’s surface. No manganese is in pure (elemental) form but a component of over 100 minerals.
Manganese is naturally found in deep wells where it has been in contact with rocks for a long time. In coal mining areas, this metal seeps through deep mining surfaces.
The manganese often occurs together with iron in the groundwater. However, manganese may occur in much lower concentrations than iron.
Manganese is indeed present in the drinking water of most modern homes. It can give the water a strong metallic taste and stain clothes.
Water from springs and wells with high manganese levels can initially appear colorless. However, when exposed to oxygen, it can turn orange-brown or black.
Finally, manganese is commonly found in western and northern countries. A study conducted by Pennsylvania State University discovered excessive manganese concentrations in about 17% of the state's water supplies.
Environmental Sources and Human Exposure
Air
The levels of manganese in the air alter depending on the proximity of point sources. They reach the ferroalloy production facilities, power plants, and coke ovens. The average level of manganese in ambient air near industrial sources is 220 to 300 ng/m3.
It was reported that it was 10 to 70 ng/m3 in urban and rural areas without point sources. The U.S. EPA estimated an average annual background concentration of 40 ng Mn/m3 in urban areas based on 102 U.S. cities.
Water
Manganese naturally occurs in many surface and groundwater sources. It also erodes soils and water. But there is a sad truth: Many human activities are responsible for manganese contamination of water in some areas.
Several pieces of evidence have shown the presence of this element in many water sources.
Snow samples from Montreal, Canada, indicated manganese concentrations near an urban expressway. Ambient manganese concentrations in seawater have also been reported, ranging from 0.4 to 10 µg/l.
The levels in freshwater range from 1 to 200 µg/l. A river water survey found dissolved manganese levels between 11 and 51 µg/l.
Fortunately, groundwater and some lakes contain fewer or reduced levels, but high levels were found in reservoirs.
The National Water-Quality Assessment Program data show manganese is higher in surface waters (in sediments and tissues of aquatic biota) than in groundwaters (in soil and rocks).
Soil
Manganese is a naturally occurring element present in nearly all soils. Natural levels range from less than 2 to 7,000 ppm. The estimated arithmetic mean concentration is 550 ppm.
Manganese accumulates in the subsoil instead of on the soil surface. The solid fraction accounts for 60-90% of soil manganese. No published reports of manganese soil ingestion exist.
Food
The foods we eat contain manganese. They are present in nuts, grains, fruits, leafy vegetables, legumes, tea, infant formula, and fish and meat. Food is the most important source of manganese exposure in the general population.
Experts suggest a daily intake of 3.5 to 7 mg of manganese for adults. Heavy tea drinkers have a higher manganese intake.
However, dietary fiber, oxalic acids, tannins, and phytic acids tend to decrease manganese absorption.
The IOM set a tolerable upper intake of 11 mg/day for adults. There is insufficient data to set tolerable upper intakes for infants or children.
Standards of Drinking Water
The presence of manganese in drinking water is not a major health concern.
Yet, it is recommended for secondary drinking water standards. It can cause health problems, making the water unsuitable for home use.
This is due to its bitter metallic taste, making it unpleasant for humans and animals to drink.
Manganese can brown laundry sinks and cause solid or dense black stains.
Drinking water should contain manganese of at least 0.05 mg/L. Private water systems catering to individual households are not subject to federal or state drinking water standards.
Thus, the standards can only provide guidelines for properly managing these water supplies.
Manganese In Drinking Water
Manganese intake from drinking is lower than the intake of food. The manganese intake would be 20µg/day for an adult, assuming a daily water intake of 2 liters. Drinking mineral water can increase manganese dosage.
Health Effects of Manganese Overexposure
Humans consume manganese through food and drinking water. Showering and bathing with manganese-containing water does not increase exposure since it does not penetrate the skin or the air.
High exposure to manganese has been associated with toxicity to the nervous system. Drinking water with high levels of manganese harms infants and young children, as it may harm their brain development. Health Canada says manganese is commonly absorbed in the body through drinking water.
Manganese is unlikely to have toxicity effects such as cancer or reproductive damage. Young children appear to absorb more manganese than the older age groups. They also tend to excrete it less than adults. This makes it important for pregnant women and children to have clean drinking water.
Testing for Manganese
You can suspect manganese if your home's water has an orange-brown stain and a bitter, metallic taste.
Only then can you easily identify the presence of manganese in your home?
However, before you treat the issue, it is best to have the water tested first. This will allow you to determine the amount, concentration, and kinds of chemicals derived from this metal.
Meanwhile, there are two types of metals inside the home water. These are known as oxidized and reduced.
Water with reduced manganese will look clear initially. But over time, it will form solid particles that look black or orange-brown. On the other hand, water with oxidized manganese will have visible solid particles drawn from the well.
How to Know the Presence of Manganese in Drinking Water
Manganese-containing water often looks purple, dark brown, or blackish. It may also stain laundry and fixtures. The only way to know is to test your water for high manganese levels.
Large public water suppliers or well owners are responsible for testing for potential contaminants. They monitor for contaminants, including manganese. Your water supplier will know if manganese levels are too high for humans to drink and tell you if this is the case.
You can test your drinking water for manganese. Contact your local health authority or a laboratory accredited for water contaminants in your water. You may also test your private well.
What To Do If There is Manganese in Drinking Water
Suppose you notice a discoloration in your water and ask for information on the cause. Manganese can cause discolored water. Yet, some concentrations are still safe to drink. As a precaution, don’t use discolored water to prepare food or infant formula. You should wait for confirmation that your drinking water is safe.
Other chemicals can cause discoloration in the waters, such as the iron found under similar conditions, such as manganese. Handwashing, showering, or bathing with high levels of manganese don’t have known health concerns.
Know when your water or water sources exceed the safe level of manganese. If this happens, choose bottled water for infants and young children.
How to Remove Manganese From Drinking Water
Water treatment technologies have shown how to remove manganese from home drinking water. These actions include water softening, distillation, filtration, and reverse osmosis.
These treatment systems can be installed at the home's entry point or used at the point of use, such as taps or faucets. Boiling water is not suggested since it can increase manganese concentration.
Drinking water treatment products can remove manganese through independent testing and certification. Factors influencing treatment choice include hardness, iron, alkalinity, sulfide, ammonia, and dissolved organic carbon concentrations.
Product certification can provide an additional level of assurance to consumers. Product certification for removing manganese down to 0.5 mg/L and 0.5 mg/L is available for cation exchange, distillation, filtration, and reverse osmosis.
Water Treatment Options
Once you have tested your water, you can determine the manganese content. Then, you can narrow down the treatment options suitable for your home.
Indeed, manganese can be effectively removed using various treatment options. This depends on the concentration and the form of the metals.
Manganese is an aesthetic problem that can potentially affect all water users. Point-of-entry (POE) treatment devices can remove it.
Oxidation filtration
The oxidation filtration can inject oxygen into the water so it can remove the impurities found in it.
Indeed, this technique can remove iron from the water. However, it will require additional chemical treatment. This is chlorine bleach to eliminate the manganese.
Multiple treatment processes may apply to your issues. Make sure your canvas compares the units and prices of various brands.
Ensure you understand the maintenance requirements for every unit.
Also, get a written warranty for the device before buying.
Water Softener
Water softeners are commonly used to treat hard water. However, they can also eliminate small amounts of manganese and iron.
This method features the use of an ion exchange process. Here, sodium replaces manganese and calcium.
Manganese and iron removal also involves exchanging manganese and iron with sodium. After that, the back-washing process can remove the metals from the softening filtering resin.
The removal efficiencies of the water softeners vary depending on the pH level, iron concentration, and water hardness.
Water softeners are generally recommended when the water's pH level is more than 6.7, the hardness is around 3 to 20 grains per gallon (50-350 mg/L), and the dissolved iron concentration is less than five mg/L.
The oxidized manganese and iron forms will produce a foul smell to the softener resin. The raw water should not come in contact with any oxidizing agents. These agents are chlorine or air before it enters the softener.
Using the softener resin bed as a mechanical filter for oxidized manganese and iron is not advised. Doing so can damage the resin bed and even require more backwashing.
If oxidized manganese and iron are present in the water, filtration should be used to remove them.
Point-of-use Reverse Osmosis
Meanwhile, point-of-use reverse osmosis treats the water at an individual tap. This is where water for cooking and other domestic activities is drawn.
This filter uses a membrane to remove unwanted molecules from the water. This enables the passage of the purified water on the other side.
Indeed, this method is easy to install and is common nowadays. However, the drawback can be it uses a lot of water. However, this can be the best option for homeowners who want to remove manganese from their drinking water.
Polyphosphate Addition
Household water containing iron concentrations of less than two mg/L can be treated with polyphosphate addition. The addition of phosphate can be less effective in the treatment of manganese.
Phosphate will be fed into the water using a chemical feed pump that often requires trial and error regarding dose adjustments.
In this example, iron can be surrounded by phosphate but cannot be eliminated from the water.
However, there are some consequences to this process. The iron will not lead to stains. But it can nevertheless produce a metallic aftertaste.
Furthermore, if too much phosphate is added to the water, it can produce a slippery liquid, which can cause diarrhea. Polyphosphate can also release sequestered iron when degraded in a water heater.
Oxidizing Filters
Oxidizing filters can filter and oxidize manganese in one unit. Usually, they use manganese-treated greensand, but other materials, such as brim, can also be used.
The manganese greensand filter's filter media is made of potassium permanganate. It forms a coating that oxidizes the dissolved manganese and removes it from the water. This powerful combination of filtration and oxidation can effectively treat raw water with dissolved and oxidized manganese.
The manganese greens and filter will need substantial maintenance. This includes regular regeneration with a potassium permanganate solution, which will be consumed during the oxidation of the dissolved metals.
Furthermore, these units allow frequent backwashing to remove the oxidized manganese particles. Note that the potassium permanganate solution used for regeneration is toxic. As such, proper handling with specific safety measures is necessary.
When maintained properly, manganese greens and filters work best with moderate levels of both oxidized and dissolved manganese.
Both are advised whenever the manganese and iron concentration is around 3 to 10 mg/L.
However, remember that maintenance, such as regeneration and backwashing, will increase directly with the concentration of metals.
Meanwhile, brim filters are just like manganese greens and filters. However, they do not need regeneration; they use the oxygen in the raw water to oxidize the metals. As such, the raw water must contain dissolved oxygen, and the pH level should be at least 7.5 to remove manganese.
Certain ideal conditions exist for efficient manganese removal, but these are highly variable with brim filters. Brim filters do not need backwashing to eliminate the accumulated oxidized metal particles.
Oxidation Followed by Filtration
The combined manganese and iron levels may exceed ten mg/L. This one actual treatment will involve oxidation plus filtration.
This process features added chemicals to convert dissolved manganese and iron into oxidized and solid forms. As such, the resulting material can be easily filtered out of the water.
Chlorine is one of the most used oxidants. However, potassium permanganate and hydrogen peroxide can also be used.
A small chemical feed pump can push the chlorine (or sodium hypochlorite) solution upstream. The solution comes from a plastic pipe coil or mixing tank. The pipe coil or the mixing tank must provide contact time for the manganese and iron precipitates to form.
An activated carbon filter may also remove residual chlorine's foul taste and odor. However, chlorine is not an advised oxidant for high manganese levels. A very high pH level is required to completely oxidize the manganese.
Significant system maintenance is required regularly for these units. As such, the solution tanks must be filled periodically. The mechanical filters also need backwashing to eliminate the accumulated manganese particles.
If a carbon filter is installed, the carbon needs replacement occasionally because it will become exhausted. The type of maintenance required is determined by the metal concentration in the raw water plus the amount of water utilized.
Berkey Water Filter System
The Berkey water filter system has been proven and tested to reduce heavy metal contaminants such as aluminum, arsenic, lead, iron, and manganese. According to the laboratory test, Berkey products can reduce the manganese by more than 99.9%.
Berkey filtration systems are innovative products available in seven different models and sizes. The systems are identical except for their maximum filtration rate and storage capacity. However, they all feature the same Black Berkey Element filters.
Black Berkey® Elements dramatically reduce trihalomethanes, inorganic minerals, heavy metals, pharmaceuticals, pesticides, VOCs, petroleum products, perfluorinated chemicals, rust, silt, sediment, radiological, and more.
The Imperial Berkey Water Filter and the Crown Berkey Water Filter are large-size Berkey products.
Imperial Berkey Water Filter
The Imperial Berkey Water Filter can dramatically reduce trihalomethanes, inorganic minerals, heavy metals, pharmaceuticals, pesticides, VOCs, petroleum products, perfluorinated chemicals, rust, silt, sediment, radiological, and more.
This system features 2 Black Berkey elements but can be upgraded into 4 or 6. Also, this can be used by small to mid to large-sized families.
With its 4.5-gallon storage capacity, no one will go thirsty inside the home. Thus, grab yours anywhere!
Crown Berkey Water Filter
The Crown Berkey model is the company's largest unit. It can provide clean drinking water to up to 150 people and is suitable for use in hospitals, churches, orphanages, and other outdoor activities.
This will ensure that no child, elderly person, or sick person ever has to drink dirty water again. Thus, grab yours anywhere!
Conclusion
While various treatment devices can reduce the manganese and iron from the water, some options must not be overlooked.
Alternative water sources should invest in water treatment options, just like Berkey Water Filters offers to its customers.
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