Water Treatment


Before any treatment is done on your water, it is best to arm yourself with some information as to what options are available to you.

Obviously the best choice to improve water quality  is to remove the source of contamination. In some cases this may be possible, i.e.removal of a leaking underground fuel tank and contaminated soil.. However, source removal is impractical in most cases. It is here that treatment options come into play.

When choosing a water treatment plan it is important to keep in mind operating and maintenance costs. Also, remember what needs to be removed from the water. Some chemicals may be easily removed using a filter, while others may need a chemical pump. In either case, the best choice is to contact a professional.

Typical water problems and some common treatments are listed below (1). 

Commom Water Problems Treatment
Bacteria Disinfection
Fuel Products Carbon filter
Hard Water Water Softener
Hydrogen Sulfide Gas Oxidizing filter, followed by a carbon filter, or chlorination followed by a sediment filter
Iron Particles Water softener or iron filter
Metals Reverse osmosis unit or distillation
Nitrates Reverse osmosis unit or distillation
Pesticides Carbon filter
pH Neutralizing filter
Sediment Fiber filter
Taste and Odors Carbon filter

Typical Treatment Systems

  1. Carbon Filters: These filters can remove most organic compounds that cause aesthetic problems (odor and taste). The longer the water is in contact with the filter, the more effective it is in removing the foreign matter. However, the filter may actually serve as a place for bacteria to live and grow. Typical carbon filters include faucet mounted, in line, line bypass, point of entry, pour through, and specialty filters. Faucet mounted filters are attached to the faucet directly. In line filters are located under the sink on the cold water supply line; this means that hot water is not filtered. Line bypass models use a separate faucet at the sink which supplies only filtered water. Water from existing fixtures will remain untreated. Point of entry (POE) systems feature a filter that treats all water entering the home. These systems will also remove volatile organic compounds that would otherwise disperse into the air. However, these are also the most expensive. Pour through filters are the most common. These filters are not attached to a water line in your house, but instead you pour the water through the filtering system. These systems are the least expensive, but they do not filter large quantities of water, and may not be the most effective type of carbon filter. The final type of filter is the specialty filter which can attach to water supply lines on refrigerators and ice makers. With all of these, it is important to realize that the filter must be replaced should the odor or taste problem reappear. These filters do not regenerate themselves.
  2. Fiber Filters: Fiber filters remove suspended material in the water. They may not be as effective at removing taste and odor problems as the carbon filter, so in some instances, it may be better to use both a fiber and carbon filter to remove these problems. These filters are made of fibrous material such as cellulose or rayon. They can be bought in a variety of weaves, but those with the smallest weaves may need frequent replacement, since more particles are trapped. These filters need to be changed when problems reoccur, just like the carbon filters. The price varies greatly, so it is best to know what type of contaminant you are dealing with to choose the most effective filter.
  3. Reverse Osmosis Units: These units are similar to an all-in-one unit in that they have different types of filters, membranes, storage tanks, and drainage tanks. They remove inorganic chemicals like nitrates. They include a filter to remove sediment, a carbon filter to remove odors and tastes, a membrane that water is forced through under pressure, a tank to hold water, and a drain to remove all the compounds that were captured. These units tend to be the most expensive, but renting one is a possibility. Additionally, there are maintenance costs to be considered. It may be best to compare the total price of the unit versus less expensive alternatives, such as bottled water.
  4. Distillers: A distiller is one of the most effective ways to clean your water. Tap water is boiled and when steam is produced, it condenses at the top of the distiller and is moved to condensing coils where it cools down and is deposited into a separate container. The contaminants are left behind. These units can be expensive depending on their capacity, maintenance, etc. They do require electricity to run. Again, a cost benefit analysis may be necessary to determine if this is the best alternative for you.
  5. Neutralizing Filters and Chemical Feed Pumps: Both of these units work similarly in that they both adjust the pH of the water. They both add neutralizing solutions to the water so that it is not corrosive. The disadvantage of these is that they tend to make the water harder due to the injection of the neutralizing agents. For suggestions on how to maintain these systems, please go to North Carolina State's web page, and look under neutralizing filters and chemical feed pumps.
  6. Disinfection: Disinfection is used to kill bacteria and microorganisms.  Chlorination is the usual method; other methods use ultraviolet light or ozone. With chlorination, a residual chlorine taste may be present, which can be removed with a carbon filter. There are professional services that will disinfect your system, but often the best way to treat a well is with shock chlorination. For suggestions and methods to use for this, please refer to North Carolina State's web page, and look under disinfection.
  7. Water Softeners: Water softeners are used to treat hard water, and involve a system that exchanges sodium ions with the calcium or magnesium present in your water. The sodium is bound to a resin that is either regenerated at the home or by the softener supplier.

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References

1. Home Drinking Water Treatment Systems. Glenda M. Herman and Gregory D. Jennings. Published by North Carolina Cooperative Extension Service, March 1996. Publication #:HE419. URL: http://www2.ncsu.edu/bae/programs/extension/publicat/wqwm/he419.html
2. Water Quality Association. Treating Taste, Odor, and Hardness Problems 1997. URL: http://www.wqa.org/consumer/treating_hardness.html
3. Siouxland, The Water FAQ, (no date) URL: http://www.siouxlan.com/siouxlan/commercial/water/faq.html#tsO



This page was prepared by S.L. Keyser, June 1997, UCD EXTOXNET FAQ Team.