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).
Typical Treatment Systems
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
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.