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Have you been thinking about installing a water treatment device in your home? Are you confused regarding whether you should install a carbon filter or a reverse osmosis system? Or, do you need a water softener or an ultraviolet system?
Whether you choose to work with a water treatment professional or do the job on your own, having an understanding of the various types of home water treatment technologies is critical to making a good decision. You may be making a substantial investment in equipment, and it’s important to make sure that the equipment is appropriate to your water treatment situation.
Step 1: Analyze Your Water
In order to determine what type of water treatment technology best suits a particular situation, it is important to first analyze the quality of the incoming water supply to a residence. This ensures the water treatment equipment you purchase will meet your family’s unique water quality needs.
For individuals who receive drinking water from a public water supply, the community’s Annual Water Quality Report provides basic information on the quality of the drinking water supply in a community. This report lists the detected contaminants, the potential source of those contaminants, and the levels at which those contaminants are present in the water supply. Additional contaminants that may be present in the home’s water supply can include lead and copper, which generally leach from the home’s plumbing.
For well water sources, private water testing may be necessary to determine if any contaminants or other conditions exist which would require water treatment. Local public health departments frequently offer basic water testing services, while private drinking water laboratories can analyze your well water for additional contaminants that are of special concern to residents living in a particular area of the United States. Common analyses performed on well water supplies include tests for bacteria (total coliform), nitrates, and hardness. In addition, well water in agricultural areas can also be checked for herbicides and pesticides or for contaminants such as radon or arsenic that can be found in many regional well water supplies.
Step 2: Understanding Water Treatment Technologies
Below are descriptions of several of the most common water treatment options available to homeowners.
Filters
Filters can be configured in many ways, and they have varying types of mechanical and chemical reduction capabilities. Although some are designed to filter water for the whole house, a majority of the systems on the market today are designed to treat water coming from a single faucet. Some filters must be filled manually, such as a pitcher, while others, such as faucet filters and under-sink systems, are actually attached directly to the plumbing. Depending upon the design and filter media used in the unit, filters are able to reduce many types of contaminants, including both aesthetic and health effects contaminants such as chlorine, chlorination by-products, lead and parasites.
Oxidation / Filtration Systems
Excessive levels of iron and manganese can be treated through a process known as oxidation, which is then followed by filtration. An oxidizing agent such as chlorine or potassium permanganate is used to oxidize the iron or manganese to an insoluble form, which can then be filtered through a special media bed. The filter media bed must be backwashed and the oxidizing agent must be replenished regularly. These systems are generally large and designed to treat water for the whole house; they can also be used to treat hydrogen sulfide.
Water softeners use a cation exchange resin to reduce the level of hardness in water. The resin exchanges sodium or potassium ions for the hardness ions (calcium and magnesium) as the water passes over the resin. The resin must be regenerated or "recharged" by passing a concentrated brine of sodium chloride or potassium chloride through the system. Water softeners are usually installed to treat water for the whole house, although a bypass valve is used to allow water to flow to the house when the system is regenerating.
Reverse Osmosis Systems
Reverse osmosis systems work by using pressure to force water through a semi-permeable membrane. These systems are normally used to produce water that contains less metals and minerals than the water that entered the system. The types of metals and minerals reduced by reverse osmosis systems include sodium and chloride to heavy metals such as copper, chromium and lead. In addition, some of these systems can also reduce contaminants such as arsenic, fluoride and nitrates.
A significant amount of wastewater can be produced by reverse osmosis systems. Because these systems produce water very slowly, a pressurized storage tank is usually installed so that water is available to meet demands for drinking and cooking. A special faucet installed at the kitchen sink to obtain water from the storage tank.
Distillation Systems
Distillation systems boil water, which vaporizes into steam, which is then condensed back into water in a separate chamber. During the distillation process, dissolved metals and minerals such as arsenic, barium, cadmium, chromium, lead and others are left behind.
There can be significant energy costs associated with using a distillation system. For this reason, distillation systems are usually designed to produce enough water for drinking and cooking only.
Ultraviolet Treatment Systems
Ultraviolet treatment systems use ultraviolet (UV) light to kill or deactivate microorganisms such as bacteria and viruses, although some systems on the market are designed for treatment of certain bacteria only.
As the efficiency of the UV system is affected by the clarity of the incoming water supply, it is important that turbid or dirty water first be treated through filtration. UV systems have no chemical or mechanical reduction properties.
Step 3: Choosing the Right Product
Different technologies vary in their ability to handle specific types of contaminants. Some are able to treat whole house water supplies, while others are more useful for single tap applications. Sometimes, it may be necessary to combine technologies in order to treat all of the contaminants that are present in your incoming water supply.
For example, a private well water user who has bacteria and hard water may choose to install both a UV system and a water softener. An individual who has problems with both Arsenic V and chlorination by-products may use a combination of reverse osmosis and carbon filtration to address both of these issues.
When choosing a specific make and model of a product or system, it is important to know that it is made from materials that are safe for water contact, that it is structurally sound, and that it will perform as claimed by the manufacturer. Many manufacturers will have their products certified by an independent organization such as NSF International, which certifies whether home water treatment products meet the design and performance requirements of national standards.
For further information on drinking water issues, including treatment options, consumers can contact the NSF Consumer Affairs Office toll-free at 1-888-99-SAFER or visit the NSF website at www.nsf.org.
