When it comes to your home’s water, nobody wants to drink yellow or brown water that comes from the tap. These colors are often caused by tannins, chemicals produced by the decomposition of vegetation and other organic matter. Tannins are what gives black tea its distinctive brown coloring, and it can give water a bitter taste and bad smell. US Water Systems offers several tannin filter system options for your home.
While tannin isn’t dangerous, it’s very unappealing and notoriously difficult to remove from water. This is because there are multiple different types of tannins, depending on the kind of vegetation that is producing them. Ultimately, different tannins are removed most effectively with different treatment methods, so finding the right tannin filter and sticking with it is often your best option.
Before you consider any type of tannin filter, it’s important to have your water tested. A complete water test will tell you if the discoloration and bad taste in your water is actually caused by tannins, and if you have any other contaminants that you should be treating. Call the Certified Water Specialists at US Water Systems at 1-800-608-8792 if you have any questions about water testing or what type of system you might need.
A relatively new type of tannin filter, charged membrane filtration (CMF) systems, use an electro-adsorptive charge to capture tannins and other negatively charged particles. The Pulsar Charged Membrane Filter System from US Water Systems uses a cartridge that includes nano-alumina fibers made from the mineral boehmite. These fibers have an electric charge that attracts negatively charged ions, including tannins, which are then absorbed. This charge also allows the filter to block particles that are much smaller than the filter’s given micron rating.
These tannin filters are also impregnated with Agion® Silver Zeolite technology, an antimicrobial additive. This helps prevents microbes from building up on the filter and causing unpleasant tastes or odors from developing.
Historically, ion exchange systems with anion resin have been used to remove tannins from drinking water. The slightly negative charge of tannin ions makes them attracted to this type of resin media, where they are exchanged for chloride. There is some indication that the resin also has absorptive properties, helping it to capture and hold the tannins.
While this method of filtering tannins can be effective, the resin must be regenerated every few days with a salt solution, adding to the operating costs. There is also a tendency for the tannins to collect in the inner matrix of the anion resin, making it very difficult to regenerate effectively. It’s also important to note that this type of ion exchange system is not the same as a water softener, which uses cation exchange resin, which attracts positively charged particles.
Some tannins may be removed from water by adding an oxidizing agent to the water and then filtering. This method is not very common, however, as it’s more expensive and complicated than either a CMF tannin filter or ion exchange. An activated carbon filter may also be of some benefit, although it cannot remove most tannins.