The Importance of Treating Manganese in Drinking Water

Manganese in drinking water has recently come under scrutiny due to its potential toxicity as well as its damage to distribution systems. A mineral similar to iron and common in Earth’s crust, manganese is found in about 95% of New England water supplies. While low concentrations are not only safe but also beneficial to human health, elevated manganese concentrations can cause taste and color issues, health risks to customers, and problems for distribution systems.

Map of soil manganese content in the U.S. (red = high manganese areas). Courtesy of U.S. Department of the Interior, U.S. Geological Survey, Mineral Resources.

Health Effects of Manganese

manganese-bloodManganese is an essential nutrient at about 2.5-5.0 mg/day, but overexposure can potentially cause serious health issues. Long term exposure to manganese can cause toxicity to the nervous system and Parkinson’s like symptoms – particularly in children, the elderly, and pregnant mothers. Young children and infants cannot break down manganese in their bodies as effectively as adults, which can cause issues in early brain development.  In recent studies, children exposed to high levels of manganese experienced learning difficulties such as ADD, hyperactivity, Pervasive Development Disorder, and memory issues. Another interesting effect of overexposure to manganese is violent behavior. Studies have shown excessive manganese decreases serotonin function and reduces dopamine levels, resulting in social withdrawal, increased depression, and aggression. Studies completed in prisons have concluded manganese toxicity contributes to delinquent behavior, and autopsies of mass murderers often show toxic levels of manganese. While these studies may be concerning, manganese ingested through drinking water is processed by the liver and reduces the risks associated with other forms of manganese exposure, such as inhaling.

State and Federal Guidelines for Manganese

Manganese oxide in rock

There are currently no enforceable federal drinking water standards for manganese. The US Environmental Protection Agency (EPA) has a secondary standard of 0.05 mg/L, a standard established to address issues of aesthetics such as discoloration, rather than health concerns. In the absence of an enforceable federal standard, the Connecticut Department of Public Health (CT DPH), has set their Action Level at 0.5 mg/L, whereas the Massachusetts Office of Research and Standards has set an Office of Research and Standards Guideline Limit (ORSGL) of 0.3 mg/L for lifetime exposure by adults and acute exposure (ten days) by infants less than one year of age.

Saving the Distribution System

Manganese-deposits-water-mainManganese deposits can build up in pipelines, pressure tanks, water heaters, and water softeners, reducing the available quantity of the water supply and pressure in the system. Manganese accumulations can become expensive for utilities when water supply or water softening equipment must be replaced. Also, energy costs can become a burden for utilities when pumping water through constricted pipes or heating water with heating rods coated with manganese deposits. Managing safe levels of manganese in drinking water is an important step in preserving valuable assets in a distribution system. The benefits associated with treating manganese greatly outweigh the long-term repair and rehabilitation costs utilities may face with high levels of manganese. To adequately manage safe levels of manganese, proper water treatment is paramount.

Proper Testing

For managing manganese in drinking water, the best treatment method is dependent on several factors including manganese concentrations, the presence of other contaminants, and existing treatment methods. Therefore, accurate testing is important before considering options or selecting treatment equipment. Typically, tests are conducted to quantify the extent of manganese concentrations, but testing of additional water parameters such as pH, oxygen content, hardness, iron, and sulfur may also be useful to determine the most appropriate water treatment method.

Phosphate Treatment

new-engljand-waterFor low concentrations of manganese, 0.3 mg/L or less, sequestering utilizing phosphate compounds is a simple, effective, and inexpensive solution. When added to water, phosphate compounds surround minerals and keep them in solution. When these compounds are put into the water system, they stabilize and disperse dissolved manganese. As a result, the manganese is not available to react with oxygen to create issues with the color, taste, or odor of drinking water. The phosphate compounds must be introduced into the water at a point where the manganese is still dissolved to maintain water clarity. This treatment process should take place before the pressure tank and as close to the well discharge point as possible. Phosphate treatment does come with a bit of risk due to the instability of most phosphate compounds at higher temperatures. If phosphate-treated water is boiled or heated, such as in a water heater, the compounds have the potential to break down and release manganese that could react with oxygen and precipitate. Also, phosphates from any source contribute to excess nutrient content in surface water.

Oxidation Followed by Filtration

manganese water treatment public
Tata & Howard completed pilot testing, design, permitting, bidding, and construction management services for the Town of Wayland’s Baldwin Pond Water Treatment Plant which included iron and manganese removal.

Among the most common forms of manganese treatment is oxidation followed by filtration. This form of treatment is ideal for manganese concentrations greater than 0.3 mg/L, where sequestering is not an option. During this process, an oxidizing chemical, often potassium permanganate, chlorine, or ozone, is pumped into the water by a small chemical metering pump that operates simultaneously with the well pump. This step converts soluble manganese into an insoluble, filterable form.  Typically, the chemical is injected in a pipeline prior to the filters, providing sufficient contact time to allow oxidation to take place. The resulting solid particles then must be filtered. Therefore, a media, membrane, or biological filter is necessary for the removal process. Common media filters include GreensandPlus and LayneOx®; membrane filtration technologies include microfiltration, ultrafiltration, and nanofiltration; and biological filtration technologies include Mangazur®. While the process may seem simple, it is important to monitor both the source water and treated water to determine the proper oxidation dosage and confirm the removal efficiency.

In Conclusion

When managing manganese levels in drinking water, it is imperative to have a well-executed balance between maximizing quality while minimizing costs. While there are many different methods to treat manganese in drinking water, the best first step to take is proper testing and an evaluation of the distribution system. Every system is different and may require unique treatment or even new source development. Manganese poses a problem for both communities and utilities alike, and proper mitigation protects the health of water system customers while greatly increasing the condition and life of the water distribution system.

Ryan Neyland, P.E. Project Manager, has over 11 years of concentrated water treatment experience including all phases of planning, design, and construction services, as well as pump station rehabilitation and SCADA experience. He holds a BS in Civil Engineering from Worcester Polytechnic Institute.


10 thoughts on “The Importance of Treating Manganese in Drinking Water”

  1. Thank you for the article. I just tested my well water and they found high levels of manganese. This is helping me to educate myself. Nice work

  2. I believe that my municipality has a problem w/maganese in the water. I moved from one side of the river to the other and suddenly I’ve had a black film and pink salt-like build up in my humidifiers, and bathroom waste basket and toilet seat. We have a lot of elderly people that have symptoms of Parkinsons in a town of only 7K. Made some calls and willing to pay for the testing, but not sure exactly how to proceed. Advice would be greatly appreciated.

    1. Dear Shannon,
      If you suspect a there may be a problem with the quality of your water, the first step is to contact your municipality. They can advise you on water quality testing and address your concerns.

  3. We seem to be having too many issues with elevated manganese in our 6K City. This happens several times a year. We have a licensed water treatment operator. What are we doing wrong?

  4. Much like Shannon, I believe that my municipality also has a problem w/maganese, at least, in the water. Our tap water is brownish and our plumbing has shown signs of excess corrosion. My plumber installed an inline, twin-filter for sediment and taste/odor. The sediment filter turns brown within a week, and the tap water eventually turns brown again. My municipality has privatized our water and will not test. We use bottled water for as much as possible, but I am trying to get away from plastics for environmental reasons. Are there respectable third-party, independent testing facilities I can contact? Please provide.

  5. Ryan:

    We are buying a house in Maine where the well water tested 0.0700 mg/L. Do we need to treat the system given these levels? Many thanks for the help.


    Richard MacKinnon

  6. Hello, I would like to know if we could be having a manganese problem in our well water. How much is safe and is a black colored ante rod an indication of a problem and who can we contact to assist in helping with this problem. Thank you.

  7. Luckily I don’t live in an area where this is prevalent, but that doesn’t mean I should ignore it. As you said here, manganese can have adverse health effects if not taken care of. I’ll probably see about getting a water treatment system adding to my home as it’s better to be safe than sorry.

  8. Should water with 24.6 manganese be filtered, 7800 total zinc. Know nothing about this any input would be wonderful thank you

Comments are closed.


Let's stay in touch.

* indicates required

Get the latest news, blogs, and insights conveniently in your inbox.

Tata & Howard • 67 Forest Street, Marlborough, MA 01752 • 508.303.9400
MA | CT | NH | AZ

Copyright ©2024 Tata & Howard. All rights reserved. Sitemap