Most people are fairly familiar with the idea of filtration. Anyone who’s ever made coffee in a coffee machine knows that you want to have a good filter to prevent coffee grounds from getting into your drink (chunky coffee is not a favorite). Filtration for well water is generally the same idea. Most filters act mechanically, physically preventing debris and contaminants from continuing with the flow of water as it moves through the filter. There are other types of filters though, that use processes such as adsorption, ion exchange, and other processes to trap and remove undesirable materials from water.
Filtration for well water on its own often will not remove microbiological contamination. It’s important to check the manufacturer’s specifications to ensure that the filter covers microbiological contamination. Most often, however, filtration of well water is part of an integrated water treatment system. Generally it’s utilized as a pre-treatment, removing large materials from water and allowing the rest of the treatment system to work more effectively. Sometimes, the filtration step comes after other components of the water treatment system, in order to trap coagulated materials (such as iron or other metals) produced from other elements of the water treatment (such as oxidation of iron from water), dependent on your specific water quality issues.
Here is a basic breakdown of some of the types of filters commonly used in water treatment:
- Carbon/activated carbon filters: These filters are usually made from organic materials such as wood, coal, bamboo, or coconut. These materials are exposed to high temperatures in an oxygen deprived environment, thereby “activating” them. This simply means their ability to absorb contaminants is increased. Activated carbon filters function chemically. The carbon bonds with, and removes some of the contaminants in from the water being filtered through it. These filters vary greatly in how effective they are and what they remove. Some of them just remove chlorine, and other objectionable tastes and odors from the water. Others can remove contaminants such as asbestos, lead, and other materials. They do not necessarily remove microbiological contamination.
- Sediment filters: These filters are designed to remove particles from the water, such as sand, rust, clay, and dirt to prevent carbon filters from clogging up too quickly. They can be made from various materials such as cotton, cellulose, polypropylene, ceramic, wound string, and glass fiber, and come in a variety of sizes. 1, 5, and 10 microns are the norm. She smaller the number, the more effectively they trap smaller particles. These filters do not necessarily remove microbiological contamination.
- Ceramic filters: Ceramic filters are generally long-lasting, lower-cost portable filters that remove a variety of contaminants, such as rust, chlorine, sediment, and even some bacteria. They do not remove all chemicals, are slow to filter and can quickly clog up. To remain effective, they also require regular maintenance (scrubbing to remove biofilm or buildup).
- Ion exchange resin filters: These filters remove fluoride, nitrates, and heavy metals, and also soften hard water. They have a variety of resins, but the most commonly used is styrene-DVB gel polymer. They do not remove pesticides, sediment, microbes, or chlorine. They can harbor bacteria, so must be maintained regularly.
There are other types of filters, depending on the issues that need to be addressed with your water quality. Each filter has a specific purpose, however, rarely are filters alone enough to remove microbiological contamination. Most often, these filters work together as part of an effective water treatment system. It’s generally best to consult a water treatment professional who can recommend the best combination of filters and treatment equipment for your unique treatment requirements.