Solving Brown Water Problems

A gentleman contacted me through an associate. He seemed to have an unusual problem with his well water and was looking for some guidance on how to solve it. When he used lots of water from the well his water would turn dirty or brown.  The major causes of brownish or dirty water are:

1. Surface infiltration or other contamination 
2. Well collapsing or water level dropping 
3. Iron (and/or manganese) in the water
4. Iron Bacteria
5. Earthquakes
6. Rust or breakdown of the metals in in the well casing or house
7.  Pollution of the groundwater from septic or other source  

In order to solve the problem, we need to figure out what was happening for the least amount of money. A well that was drying out or collapsing bring up brown water, but generally it would stop if you let the well rest for a few hours. This brown water would last for days at a time, but there was always plenty of water. First thing I needed to do was listen to the gentleman who called me. We talked for almost two hours as I heard his story. Slowly the information I needed to help him came out in little bits as he talked. He had gathered lots of information on his well from county files, the well service company, the water treatment company he had dealt with first.

His well was about 21 years old and was 320 feet deep. It was drilled through 150 feet of clay and sand then 170 feet through granite and sand stone. The well had a casing that ran to 180 feet below grade and was properly grouted. At completion the well had a yield of 30 gallons a minute without any measurable drawdown.  I know this geology it is only about 8 to 10 miles from my house. This is fractured rock it is unlikely that the well was going dry. The well was properly built and it was not likely to be collapsing. We would save hiring a company to use a camera to look at the well as a last resort. So what was going on?

As the gentleman spoke, I told him I would need more information. I needed some water analysis. That’s when he told me that he just had his water tested when he had replaced his water softener and the other equipment which turned out to be a neutralizer. This gave me an idea of what was going on. I had him test the water ahead of the water treatment system and after the treatment when the water turned brown again after using lots of water. 

Below are some of the test results (the rest of the test results only eliminated other possibilities and are not pertinent to our discussion): 

The test results tell a story: When the new water softener and neutralizer were installed they were adjusted properly to give neutral water and iron just at the EPA MCL. However, the untreated water has a combined iron and manganese level of 5.366 mg/L, beyond the ability of a water softener to effectively treat iron and manganese and  there is a lot of iron bacteria which could further reduce the effectiveness of the water softener to remove iron. At September the iron was already breaking out. The sample taken after the treatment system and using lots of water shows massive amounts of iron! The water softener became overwhelmed with too much iron and was allowing untreated water through and shedding excess iron. 

 His water is naturally slightly acid and soft. He never needed a water softener. What he needs is to first treat the well for iron bacteria to push it back and start with a "clean slate." Then remove the water softener and install a an iron aeration and filtration system. This system is not effective on water with iron/ manganese bacteria, but is very effective soluble iron and manganese that are present in this well. The neutralizer should be kept to maintain the pH in the operating range for the iron aeration and filtration system. That should solve the problem. I'll see if we can get this straightened out in the next couple of weeks. An iron aeration and filtration system can remove up to 15 mg/L of iron and manganese. 

Iron and manganese exist in many different chemical forms. Dissolved iron and manganese are easily oxidized to a solid form by mixing with air. In surface water, iron and manganese are most likely to be trapped within suspended organic matter particles. Groundwater tends to be an oxygen poor environment; the deeper the aquifer the less dissolved oxygen is present. Iron and manganese carbonates in an oxygen poor environment are relatively soluble and can cause high levels of dissolved iron and manganese to be carried from a deep well. If sulfur is present in the water then the iron will form iron sulfide rather than iron carbonate and the water may have the familiar unpleasant rotten egg smell. 

When the iron and manganese are oxidized reddish brown or black particles form and settle out as water stands. These particles are often found trapped in washing machine filters, water treatment equipment, in plumbing fixtures and on clothing, dishes and utensils. When he sampled the well for me he took two samples of the brown water and put them on the shelf. The next time he checked them they were clear with the brown particles settled on the bottom.

Some types of bacteria react with soluble forms of iron and manganese and form persistent bacterial contamination in a water system. The reaction changes the iron and manganese from a soluble form into a less soluble form, thus causing precipitation and accumulation of black or reddish brown gelatinous material (slime). Masses of mucous, iron, and/or manganese can clog plumbing and impact the functioning of water treatment equipment. They also slough off in globs that become iron or manganese stains on laundry. Over time the bacteria in the well increases and precipitation caused by bacteria occurs faster and the slime tends to concentrate staining making it more annoying.

All systems of removing iron and manganese essentially involve oxidation of the soluble form or killing and removal of the iron bacteria. When the total combined iron and manganese concentration is less than 15 mg/l, an oxidizing filter also called an iron filter is recommended. These filters convert dissolved iron, manganese, or hydrogen sulfide into a solid form and then filters the solid particles from water. The device uses the same casing as other products by the manufacturer, but the media in the oxidizing filter is typically a manganese-treated greensand or manufactured silica gel zeolite coated with manganese dioxide, plastic resin beads, or other trade named media. With lots of dissolved iron it is necessary to have an iron filter with an air bubble or other air blown in. Maintenance typically involves periodically recharging media with an oxidizing agent and backwashing. Iron filters need to be selected to match the pH of the water. If pH is not in the range of any of the iron filters, then a neutralizer needs to be used or it is best to use chemical oxidation if that is undesirable.

Often when there is hard water and low levels of iron and manganese, a water softener can be utilized to remove both the hardness and the iron and manganese. When the iron and manganese present in a combined concentrations are less than 5 mg/L this will work.  It is important to check the manufacturer’s maximum iron removal level recommendations before purchasing a unit as they are more expensive than iron aeration and filtration systems. This strategy should only be used when the water is hard, otherwise it is a waste of money. However, in years past using a water softener to remove iron was standard practice and there are lots of unnecessary old water softeners out there. 

As you can see, turbidity the measure of the degree to which the water loses its transparency due to the presence of suspended particulates is a problem. The more total suspended solids in the water, the murkier it seems and the higher the turbidity. Turbidity can be caused by silica, soil finds, iron or iron bacteria. Generally, iron bacteria and other reducing bacteria are not problems in the first couple of years of a well. It takes time for the bacteria introduced during drilling to spread. Iron bacteria are present in most soils and can be introduced into a well or water system during drilling, repair, or service. The most common causes of turbidity in wells are dirt and colloidal solids like the iron that are too small and too fine to settle out properly. However, after the jars of water sat on the shelf for a while the water became clear. So, it should be okay.