Approximately 2.6 million Americans rely on groundwater with elevated levels of manganese. If you have a private well, you may be one of them.
If you have noticed a metallic taste or dark gray staining in your water, manganese is likely to blame.
Manganese is a common contaminant in well water that often comes with iron, which can turn your water rust-red. In low doses, these chemicals affect the taste and odor of your water. However, high concentrations pose a health risk.
It's essential to remove manganese from your well water. Here's how to do it.
What is Manganese?
Manganese is a metallic element with the symbol Mn. It's an essential mineral for the human body and can be found in trace amounts in the liver, kidneys, and pancreas. However, excessive amounts of manganese in well water can be a contaminant. It can exist in two forms: soluble and insoluble manganese. Bacterial growth of manganese can also occur in wells and water heaters.
Soluble Manganese (Manganous Manganese)
Manganese in the form of manganous manganese is the most commonly found in drinking water. This type of manganese is fully dissolved in the water, similar to sugar in tea.
Soluble manganese isn't visible in water and can't be removed through simple filtration. We will explore methods to transform manganous manganese into a precipitate form before filtering it out.
Insoluble Manganese (Manganese Precipitation)
Manganese precipitation is a solid form of manganese that occurs in water when dissolved manganese reacts with oxygen and solidifies. If both iron and manganese are present in the well water, iron will oxidize first as it requires a pH range of 7.5 to 8. Dissolved manganese is more common as it needs a pH of 8 or higher to oxidize.
Insoluble manganese can cause the water to turn dark grey or black, making it easily detectable. It can be removed from the water using a low-micron filter.
Manganese in well water can be present in either dissolved (Manganous Manganese) or precipitated (Manganic Manganese) form. However, manganese bacteria can become a significant issue if they proliferate in your well or water heater.
Manganese bacteria are a group of bacteria that utilize manganese as a source of energy. They don't pose any health threats as they are non-pathogenic, but they do produce black sludge that can harm your appliances and plumbing systems.
How Does Manganese Get Into Well Water?
Manganese is a common element found in the earth's crust and is the fifth most common metal, making up 0.1% of it. As a result, it's not surprising to find trace amounts of manganese in well water.
The majority of manganese in well water comes from groundwater and can also leach into the water through agricultural practices. Higher concentrations of manganese are usually found near rivers.
Wells with high concentrations of manganese, ranging from 2 to 3 parts per million (PPM), can be 40 to 60 times higher than the recommended limit set by the Environmental Protection Agency (EPA).
Are There Benefits of Manganese in Drinking Water?
There are no benefits to having manganese in drinking water. Manganese is an essential nutrient that can be obtained through various food sources such as fruits and vegetables. Most people get enough manganese in their diet, ranging from 0.7 to 10.9 mg/day. Manganese deficiency is rare and its impact on health is not scientifically established.
Harmful Effects of Manganese in Drinking Water
Health Impacts of Manganese Toxicity
Manganese toxicity can have several negative effects on your health:
- Neurological and Cognitive Disorders: High levels of manganese can cause manganism, a condition linked to Parkinson’s disease. Symptoms include loss of appetite, depression, and body spasms. Long-term exposure to high manganese levels can also cause developmental brain issues in both adults and children.
- Anemia: Manganese exposure interferes with the body's ability to absorb and process iron, leading to anemia with symptoms such as fatigue, dizziness, and an irregular heartbeat.
- Children: Young children, especially those who are bottle-fed, are particularly vulnerable to manganese exposure. The Connecticut Department of Public Health recommends a manganese content of less than 0.3 mg/L in drinking water for pregnant women and children.
Taste, Smell, And Appearance
Elevated levels of manganese in drinking water can affect its taste, smell, and appearance. The water can turn dark and have a bitter, metallic taste, affecting the taste of any food cooked with it.
How Does Manganese in Water Damage Your Home?
Manganese in water can cause dark stains on your sinks, bathtub, and toilet bowl. It can also accumulate in pipes, leading to erosion and black sludge emerging from your faucet. The presence of manganese in drinking water not only affects its taste, but it can also cause costly repairs in the future.
Additionally, excessive levels of manganese in drinking water can clog water heaters and pipes, reducing water pressure.
Safe Limits for Manganese Set by the EPA
The EPA has set the health advisory limit (HAL) for manganese at 0.3 mg/L, which is equivalent to 0.3 PPM. At this level, manganese is a serious health concern. The EPA advises that children shouldn't consume drinking water with manganese levels higher than 0.3 mg/L for more than 10 days a year. For adults, it recommends not consuming water with manganese levels over 1 mg/L for more than 10 days a year.
However, manganese can affect the taste and odor of water at much lower concentrations and damage plumbing. The EPA has also set a secondary standard of 0.05mg/L for manganese, which is 60 times lower than the health advisory limit. At 0.05 mg/L, manganese will cause black spots in drinking water, tea, and laundry.
How to Detect Manganese in Drinking Water
If your drinking water tastes bitter and metallic or you see black stains on your appliances, it may contain an excess of manganese. Unlike iron, manganese does not form a precipitate in drinking water at its usual pH. To detect manganese, look in your dishwasher. Dishwasher detergents raise the pH of water to over 8, causing manganese to solidify.
How Do You Test for Manganese in Water?
To test for manganese in water, you can use a home water test strip. Simply dip the strip into your water supply and read the results, which will indicate the manganese concentration up to 1.6 PPM.
For a more accurate and comprehensive test, consider a professional test from local water quality experts. Find a licensed laboratory through local environmental departments or county government offices.
The EPA considers manganese concentrations of 0.05 mg/L, 0.3 mg/L, and 1 mg/L to be disruptive to health and home. To ensure the safety of your drinking water, it's important to know the level of manganese in your water.
Manganese in water may affect the taste but may not necessarily discolor the water if the water has a low pH. The CDC recommends testing your well at least once a year for coliform bacteria, lead, and TDS (total dissolved solids).
How to Remove Manganese from Well Water
Soluble manganese must first be oxidized into a precipitate by an oxidizing media. The manganese, now in precipitate form, can be filtered by a submicron filter. Air injection filters, manganese greensand, and Birm are commonly used for oxidation.
Removing manganese requires a similar process to removing iron from well water, but oxidation can only happen at a slightly higher pH of 8 and above. Premium well water filtration systems combine oxidation and submicron filtering.
Oxidizing media converts dissolved manganese into a precipitate form through a chemical reaction. It's paired with a sediment filter to remove the solid manganese.
- Manganese Greensand is a filter media made of glauconite grains coated with manganese dioxide. This coating creates oxidation of soluble manganese, removing it from water. Springwell's Well Water Filtration System uses this method to effectively remove 1 PPM of manganese from well water.
- Air Injection process increases the dissolved oxygen content in water by applying pressure. This creates optimal conditions for oxidizing soluble manganese. If the water's pH is low, soda ash or caustic soda may be added during aeration. Once oxidation is complete, a sediment filter removes the precipitated manganese.
- Chlorination uses chlorine as the oxidizer and is effective in removing dissolved manganese. However, it requires longer contact time compared to other methods. After the oxidation process, further filtering is necessary to remove the solid manganese. But be aware, the high chlorine content in the water can damage certain filter media, such as Birm.
Catalytic Filter Media
This type of filter media can oxidize small concentrations of manganese when there is a high oxygen content and pH level in the water. Birm and carbon filter media, along with a sediment filter, are used for this purpose. The sediment filter captures the oxidized manganese precipitate.
To effectively remove manganese, catalytic filter media requires a pH level over 8. This pH level is common in private wells, but before choosing this type of filter media, make sure your well has a pH in the appropriate range.
Biological oxidation isn't yet available commercially, but research shows potential for it to be an effective solution in the future. The method employs manganese-oxidizing bacteria to convert manganese into precipitate form. Note that these bacteria are different from the manganese bacteria that consume manganese and create black slime.
A basic cartridge-style sediment filter is sufficient to remove manganic manganese if it's in precipitate form. These filters are also affordable.
However, if the manganese is in its soluble form (due to the specific conditions required for it to oxidize,) a filtration system that converts it into precipitate is needed before the sediment filter removes it from drinking water.
Water softeners designed for wells can effectively remove soluble manganese from well water under the right conditions. However, it shouldn't be used to remove precipitate manganese as it can damage the water softener. Before using a water softener, ensure the manganese concentration is low and the Total Dissolved Solids (TDS) level in your water isn't excessive.
Kinetic Degradation Flux (KDF)
KDF filters utilize redox, an oxidation/reduction process, to eliminate a variety of contaminants, including manganese, lead, heavy metals, and chlorine.
Reverse osmosis (RO) is an effective filtration method that removes most contaminants, including manganese. It works by forcing water through a fine membrane under pressure. However, it's only suitable for removing low concentrations of manganese as higher concentrations can damage the membrane. RO filtration systems are also expensive.
How to Remove Manganese Bacteria
To remove manganese bacteria, shock chlorination is recommended. This involves using a large dose of chlorine, around 200 PPM, to kill the bacteria in your well or water heater. The chlorination process should reach the bottom of the well to ensure that the well pump and pipes are effectively disinfected.
Off-grid water supplies offer a solution to the added chlorine, fluoride, and expensive utility bills from municipal water. However, they may also contain contaminants.
Manganese is an important mineral for our bodies, but a balanced diet of fruits and vegetables provides enough of it.
Having a high level of manganese in a private well water may pose a health risk and result in unpleasant odor in drinking water. Installing a premium well water filtration system can protect your health and home.