With more than 30 years’ experience in the residential and commercial water treatment industry, Mark Nelson is a Class 1 Drinking-Water Operator and a CBWA (Canadian Bottled Water Association) Certified Plant Operator. As founder and president of Nelson Water in Ottawa, Mark focuses on dealing with challenging water treatment system designs for problem water. He also heads the largest water bottling plant in the city of Ottawa with a delivery network throughout the Valley.
What are Tannins?
Tannins are released into the soil and groundwater when plant matter decomposes. They are found naturally in many different types of vegetation. In reality, tannins are not a major health concern, in fact, we ingest them on a daily basis in our food and certain beverages (wines for one), but the biochemicals in tannins are the reason why water becomes discolored and tastes bitter. Tannins are usually accompanied by humic acid and fulvic acid. In larger concentrations these substances cause many other problems for your household.
If your water has a yellow or brown tint and a bitter taste, you may have tannins in your water supply. Although not life threatening, they do bring with them a multitude of bothersome headaches. We will take a closer look at what tannins are, the kinds of problems they cause and some methods to remove them.
The Problems with Tannins
If you’ve ever consumed a cup of tea, you’ve ingested Tannins. Tannins leave a brownish stain in your cup. Over time, that cup can become quite difficult to clean, as the tea stains become worse. Now envision your whole water supply infused with Tannins and you will be able to appreciate the scale of the problem. Tannins can make laundry appear dirty, and they tend to stain porcelain plumbing fixtures and crockery. Drinking water appears unpalatably brown and unsafe, and will taste bitter with a very unpleasant odor.
Can You Remove Tannins from Your Water Supply?
In short… yes. But the difference in the types of tannins and their accompanying humic acids means that there is not a one size fits all solution. Tannins can vary significantly based on the composition of the decaying plant life they derive from. A method that works well for one Tannin problem, may not work for another just a few kilometers away because the two tannins could be quite different. An effective treatment in the past was a styrene based macroporous anion resin, but it does not always work well. More recently, acrylic resins have been used to greater effect as they have a macroporous structure that regenerates more effectively.
The Best Method for Tannin Elimination
The consensus among water treatment professionals is that water treated with a water softener and then treated specifically for tannins is the most effective approach. The softening process (think of it almost as “pre-conditioning”) removes minerals and metals that cause hardness. Both of these substances have a negative impact on the effectiveness of tannin removing resins.
In our practice, we use an EcoWater ESS 1100XR32 with a specialty resin. This unit regenerates with salt like a conventional water softener, but with the specialty resin designed specifically to remove tannins. When tannins combine with other elements such as iron, a chemical injection system will likely be required.
Although the consumption of tannin is not life threatening, it can have negative consequences on your home. The key answer you are looking for is that with modern water softeners/water conditioners and filtration systems, tannins can indeed be eliminated. For more information on how this might be accomplished in your own home, talk to your local CWQA certified water treatment professional. They should have all the answers you need.