Water Filtration Methods

Water Filtration Methods: What they do and why you might choose them.

Most Water filter reviews will point out that while any filter will make water cleaner, there are advantages and disadvantages to most of them. Hopefully this summary and review will help you decide the method of filtration that will work best for you, then you can decide the type of filter to choose.

1) Mechanical Filtration, 2) Micro-Pore Membranes, 3) Absorption by Activated Carbon and Carbon Block Filtration, 4) Oxidation-Reduction (Redox), 5) Muti-stage Ultra Filtration, 6) Reverse Osmosis Filtration, 7) Distillation, 8) Fluoride and Heavy Metal Filters, 9) De-ionizers and Anti-scale Filters, 10) Water Softeners

1) Mechanical Filtration:

This is simply having a barrier that has holes smaller than what it is that you want to filter out. This method of filtration removes tiny particles that are suspended in the water such as dirt, silt, sand, sediment, rust and other un-dissolved substances. As water passes through the the media the particles are trapped or blocked and effectively removed from your water. Depending on the quality and/or type of the filtering media particulates as small as 0.3 microns can be stripped from your drinking water. This will remove many bacteria and cysts. For reference purposes, a micron is equal to 1/25,000 of an inch, the diameter of one strand of your hair is around 100 microns. A variety of materials are used to produce mechanical filtering media. Ceramics and various resins comprise the majority of this type of water filtration. Mechanical filtration will be a part of all of the best designed water filters .

2) Micro-Pore Membranes

A type of Mechanical filtration, this simply employes membrane barriers with very small pore size (often .3 to 1.0 micron) so that they can remove certain contaminants such as cysts, micro organisms and bacteria such as Giardia or E. coli which are too large to pass through.

3) Absorption by Activated Carbon and Carbon Block Filtration:

Activated carbon absorbs organic substances that cause your water to smell and taste bad. It also has the ability to remove pesticides, chlorine and its byproducts. This product is very porous, so much so that the carbon in an average countertop filter would have a surface area of 200 football fields. The term "activated" refers to a process that makes the carbon more porous than it is naturally. Activation is achieved using steam, a chemical process or by controlled production processes while creating the carbon Activated carbon works like this: Another common home filtration system, here contaminants merge and bond with granules of carbon. While it is one of the best water filters to remove organic compounds it can still leave metals or other scale-causing contaminants. In addition, its ability to perform depends on largely on how much contamination runs through it (the more, the sooner it is rendered useless). As water flows over the surface at sufficient pressure dissolved chemicals stick to the carbon allowing the water to continue. This process is called absorption.

Activated carbon can be grouped into three categories: carbon block (CB), granulated activated carbon (GAC) and powdered activated carbon (PAC). The CB variety works better at higher pressures, where the GAC is less expensive and works well with municipally supplied water. The PAC variety is less common. The raw materials used for making activated carbon are usually coconut shell, wood, lignite, coal and the like. Coconut shell is considered to be the preferred material when making filters for drinking water due to its tendency to leave the water tasting better

4) Oxidation-Reduction (Redox)

Oxidation/Reduction Technology is a process where by electrons from one atom or molecule are transferred to another. What this means is that when you mix two dissimilar metals you get an electrochemical process that oxidizes a host of chemicals found in our municipal water supplies. The heavy metals like aluminum, cadmium, lead and chromium are removed by the electrochemical process. These metals are attracted to the media, very similar to a magnet.

5) Muti-stage Ultra Filtration

Most water filter reviews will say that a multi-step system is the best way to produce the cleanest, purest water. It just makes sense that running the water through more than one filter or cartridge type, such as micro- pore, carbon block, ionization or reverse osmosis, ensures that the end result is better than if just one step was involved. A water filter review of this type of product will generally discuss the difference steps that are involved in the process. Multi-step purifiers often have an ion exchange where the lead elements are exchanged for potassium. Sediment and other larger particles should be removed as well as microorganisms so that there is nothing in the purifier tank but absolutely pure water.

6) Reverse Osmosis Filtration

Reverse Osmosis water filters involves pushing water through a membrane with extremely small pores under high pressure. In doing so, much of the harmful compounds are kept out (as they can't pass through the pores); however, minerals which the body can benefit from are also retained. In many cases, other synthetic chemicals can also get through. As with most reverse osmosis filtration. The best selling home water filters on the market today are so-called reverse osmosis water purifiers, but these are actually not the best choice. They do a pretty good job of eliminating contaminants, but they also remove essential minerals that the human body needs to stay in optimal health.

The human body has evolved to drink water that contains important minerals, such as magnesium, calcium, potassium, and many more. Nowhere on earth does de-mineralized water appear naturally. Animals do not drink it. This kind of de-mineralized water causes the human body to lose minerals, which leads to bad health, frail bones and a host of other problems.

7) Distillation

Although not common in homes, distillation is still commonly used and is one of the oldest methods of filtration. The process is boiling the water, leaving behind inorganic contaminants, and then cooling and condensing it back in its liquid, drinkable form. Most bacteria are destroyed during the boiling process. A downside is not all chemicals are removed, since some boil faster and easier and therefore cool with the rest. Distillation also removes many of the benefical minerals from the water as well. Technically, pure means the absence of anything different. 100% pure H20 then would contain no minerals. Traces of minerals like sodium and potassium are good for your health and they improve the taste of your beverages. Water distillation is a process where you boil your water, capture the steam and then condense it into a container. This process removes the vast majority of the solid contaminants including fluoride, lead, chlorine, volatile organic compounds and just about all other contaminants. Home water distillers can be purchased starting at $100 but their out put is low at about 1 gallon per .5.5 hours. Water distillers that produce 1 gallon per 3.5 hours runs about $200. Self filling water distillers start around $500. Water distillers should have a charcoal or carbon incorporated into their filtration system.  There are differing views as to whether or not distilled water is the best method to remove fluoride. Many believe the minerals found in water naturally should not be removed for optimum health benefits. Others feel that the quantity of the trace minerals found in water is so small that it really doesn't matter and it's better to err on the side of caution. Both views have their merits.  There is also the issue of water distillers requiring additional energy to operate and the need for maintenance and cleaning more often than pressure operated filters. If you need the benefit of water stripped of fluoride, all minerals, metals and organic compounds then distiller water is the choice for you.

8) Fluoride and Heavy Metal Filters
Flouride, Lead and Arsenic filters:

Fluoride Water Filters are utilizing high capacity synthetic absorbent media that is highly selective for Fluoride , lead and arsenic. This high capacity synthetic absorbent media's extremely high surface area and pore distribution gives this media the highest possible operating capacity and lowest possible leakage.

It is a synthetic aluminum oxide that is specially processed to have a minimum of fines and other foreign matter, removes metals through a combination of adsorption and chemical reaction with the media, thus the removal is not dependent on ion exchange and has a uniform particle size similar to ion exchange resins. It has minimal shrinkage or swelling and low pressure loss. It is physically stable and can be used over a wide pH range.

Iron and Manganese filters:

The media filter is an aluminum silicate media coated with manganese dioxide. This coating is highly concentrated with oxygen and acts as an insoluble catalyst to enhance the reaction between dissolved oxygen and the the iron compounds. In essence, the dissolved iron is oxidized at the surface of the media into a rust particle that can be effectively filtered from the water. The precipitated iron and manganese can then be easily removed from the system during backwash. No chemical regeneration is required and nothing is imparted into the drinking water.

Heavy metals can also be removed with Re-Dox technology. Oxidation/Reduction Technology is a process where by electrons from one atom or molecule are transferred to another. What this means is that when you mix two dissimilar metals you get an electrochemical process that oxidizes a host of chemicals found in our municipal water supplies. The heavy metals like aluminum, cadmium, lead and chromium are removed by the electrochemical process. These metals are attracted to the media, very similar to a magnet.

9) De-ionizers and Anti-scale Filters

Anti-Scale Systems/Saltless Water Conditioner is a new technology which transforms the calcium (hardness) of the water into mechanically stable and heat resistant calcite crystals (nanometer size) which no longer cause lime deposits. The calcium is simply rinsed away. Calcium (hardness) creates scale in pipes, on appliances and other plumbing surfaces. This leads to higher heating and energy costs and expensive repairs to appliances. Scale can also be a source for bacteria to grow, which can be a health concern in drinking water applications.

It also removes the already existing scale from pipes and heat exchanger surfaces (descalingeffect) and further protect the system from future formation of scale (scale protection effect).

Features and Benefits:

*Complete scale prevention in all pipes, on appliances and other plumbing surface exchangers.

*100% removal of old calcium deposits in all pipes, on appliances and other plumbing surface
*Formation of a layer for corrosion prevention
*No electricity required
*Easy installation and setup
*No salt, chemicals or regeneration
*No backwashing means no wasted water and no drain to install
*Less soap or detergents required
* Perfect where salt-based softeners are banned or undesired
*Nearly maintenance free.

The media works with a catalytic surface. Once water contact occurs the nanocrystalls on the ceramic surface of the media create calcium crystals from the positive calcium ions. These calcium crystals are neutral and can not attach to any surfaces. This applies to pipes, appliances, water heaters as well as machinery surfaces. This works with cold water as well as with hot water. The nano sized crystals are rinsed away by the water flow. All harmful characteristics of the calcium are neutralized. The important health advantages of the calcium remain intact because the crystals dissolve at a pH of 3 and are then available to the body.

10) Water Softeners

Water is hard when it contains minerals like magnesium and calcium. You may see staining on your sinks, tubs, showers, and clothing. You may also notice less lather from your shampoos and soaps and even a feeling of film on your skin. All these are symptoms of the need for softened water. Also hard water causes a higher risk of lime scale deposits in household water systems. Due to this lime scale build-up, pipes are blocked and the efficiency of hot boilers and tanks is reduced. This increases the cost of domestic water heating by about fifteen to twenty percent. Another negative effect of lime scale is that it has damaging effects on household machinery, such as laundry machines. Water softening means expanding the life span of household machine, such as laundry machines, and the life span of pipelines. It also contributes to the improved working, and longer lifespan of solar heating systems, air conditioning units and many other water-based applications.

 

Water is softened or conditioned by replacing hard ions like magnesium and calcium with softer sodium or potassium ions. Water softeners must be regenerated regularly, renewing their ability to remove hardness from water. Time-initiated or solid state softeners regenerate at a fixed time when their softening capacity is predicted to be low. Demand-initiated softeners regenerate automatically when they sense their capacity is low.  The benefits of water softeners, if needed are:
Keeps skin and hair healthy looking
Dishes are cleaner, with less soap and hard water spotting.
Tubs, showers, and sinks are easier to clean, thanks to reduced hard water build-up
Clothes are softer, cleaner, brighter, and last longer
Keeps all fixtures from scaling and corrosion
Saves time, money and energy

Towels washed in water softened by softeners need 1/3 less detergent and come out 45% whiter

Also see #9) De-ionizers and Anti-scale Filters