Many people fail to appreciate how vulnerable our drinking water is to contamination by all sorts of chemicals organic and inorganic compounds. It's no secret that over the past few years the level of contamination in our water supplies have increased dramatically. What once was a luxury item has now become an essential necessity in our homes, and that is some form of water purifier. Many people having installed a filtration system in their home are curious how does a water purifier work?
The first method we will look at is reverse osmosis, which has been around for over 100 years. The basic system uses a membrane, which is semi-permeable. This allows the passage of water but rejects the movement of contaminants. There are two distinct types of membrane, Thin Film Composite (TFC) and Cellulose Triacetate (CTA). Although the TFC membranes are more efficient their weakness is they are easily degraded by chlorine and need to be replaced frequently.
In order to stop a build up of contaminants at the membrane, high quality reverse osmosis systems employ a method known as cross-flow. This allows some of the water to pass through the membrane whilst the remainder carrying the contaminants goes down the drain. The whole process depends on having sufficient water pressure to force the water through the membrane. However, the normal household water pressure is quite adequate to do this.
Reverse osmosis generally requires some form of filtration to remove any sediment present in the water, failure to do so will result in fouling of the membrane. The process is fairly slow and will only produce around 15 gallons of purified water each day. Also, to achieve this it may require 3 to 10 gallons of untreated water to produce 1 gallon of purified. This means if your water is metered this can work out to be very expensive.
Carbon has been used for many years to absorb contaminants, and just a small amount can absorb many different types of chemicals. As water passes through the carbon so the pollutants are removed. There are several different types of carbon that are available and are used as water filters. Although it costs just a little more coconut shell is the most effective.
Organic compounds are removed by carbon in its natural state but in order to remove chemicals activated carbon is used. It is called this is because a small positive charge is added to it and this attracts the chemical impurities.
There are a number of factors, which determine the efficiency of a carbon filter. The amount of carbon is one, obviously the more carbon the better. Another factor is how long the contaminants spend in contact with the carbon. This means the slower the flow of water the higher the absorption rate.
An easy way to judge the effectiveness of carbon filters is by the size of the smallest particle, they are able to remove. They range from 50 microns to 0.5 microns, which is the most effective.
Whether you choose a point-of-use or a whole house water purifier some form of protection against water contamination is essential for you and your family. Of course now you know how does a water purifier work you will be able to choose a model that is perfect for your home. So what are you waiting for?
