Wednesday, August 10, 2011

Whole House Water Purification - The What, How and the Best

Whole house water purification means just what it says. The idea is to filter all the water coming into your home by installing a water filter system near the point your water supply line enters the home. That way all the water past that point has been filtered and you can have good, safe water everywhere, in your sinks, showers, bathtubs and even for laundry and dishwashers. In this article we will look at whole house water purification systems, what they do, how they do it, and the best technology to use to get the job done for you.

1. What do they do?

WATER SOFTENER COMPARISON

Simply put, any good whole house water purifier should give you clean, healthy water by removing virtually all (over 99%) of the debris and harmful contaminants from your water. This would include chlorine, THMs or the toxic by-products of chlorine, SOCs or synthetic organic chemicals, lead, weed killers, insecticides, pesticides, pharmaceutical drugs, etc., the list goes on and on.

2. How do these systems remove the pollutants?

First, keep in mind there is no single filter that will do the job, all whole house water purifiers will consist of a series of filters one after another. The series will begin with a pre-filter to remove larger particles of debris that might clog the finer filters to follow.

Next, will likely be a carbon filter of some type. Activated carbon is recognized by the EPA, Environmental Protection Agency, as being the best available technology for removing chlorine, THMs, and VOCs (volatile organic chemicals).

The third stage of filtering could come from distillation, reverse osmosis, or a system utilizing adsorption with activated charcoal, sub-micron filters and ion exchange, called selective filtration or multi-stage filtration.

Distillation is a process that passes water over a heated coil to form steam that rises to a cooling tank and condenses back into a liquid. This process kills any remaining bacteria in the water, and removes inorganic compounds like lead, calcium, potassium, etc. The process does not remove organic chemicals, so, a distiller must always be used in combination with a carbon filter.

Distillation units operate slowly, producing only three or four gallons of filtered water a day, and, at a relatively high energy cost due to the electricity used.

Reverse osmosis units push water under pressure against a semi-permeable membrane with very fine pores, the size of water molecules. The process rejects certain contaminants, minerals, and even a large part of the water. Most SOCs, such as herbicides and pesticides, are even smaller, molecularly speaking, than water and will pass through these membranes and will not be filtered out. That is why these systems must be used in combination with a carbon filter.

Most reverse osmosis systems produce only a gallon or two of filtered water an hour and will waste two or three times that for every gallon produced. They require a storage tank to create any volume of filtered water and, sometimes, a booster pump as well to maintain pressure. Initial costs for the various components and maintenance costs make these units about equal in cost with distillation.

Both distillation and reverse osmosis systems remove all the minerals from the water, including the ones our bodies need. When the minerals are removed, the water changes its acidity and will try to re-balance itself by stripping needed minerals, like calcium, from the body. For this reason, many health experts consider this water unhealthy.

The third system starts with the adsorptive power of activated charcoal and blends it with a chemically charged resin to create a very different, but highly effective, filter media.

This blend is compressed into a solid carbon block in which contaminants bond, either chemically or physically, to the adsorptive surface. Chemicals like chlorine, drugs, pesticides, etc., physically bond to the surface of the charcoal thru adsorption, and minerals, such as lead and mercury, are chemically altered by the resin through an ion exchange, allowing them to be filtered out as well. Finally, even very tiny chlorine-resistant cysts, such as giardia and cryptosporidium, and any remaining inorganic contaminants, are trapped in the blocks tiny pore structure.

It is true that selective filtration was not designed to handle salty water, but, since most of the nation does not have that problem, it is not likely to be an issue.

The big pluses with these systems are the initial cost and their low operating costs. They process water very quickly, with a very small loss of water pressure, so they don't require booster pumps or storage tanks.

3. What system will work best for you?

If you are dealing with a salt water problem, you definitely want to go with a reverse osmosis system. Yeah, it is wasteful and expensive but it will clean up the water, believe me.

If you don't have the salt problem, you want to use the selective filtration process. Their systems are very compact, less expensive to own and operate and, if they are installed properly, they work virtually maintenance free.

Whole House Water Purification - The What, How and the Best

WATER SOFTENER COMPARISON

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