Reverse Osmosis

Reverse Osmosis(RO) is the most thorough of filtration solutions available in the market today.  Also known as hyper-filtration, it removes more contaminants than any other type of water filtration. RO technology uses a semi-permeable membrane which restricts any particle larger than a water molecule from passing through. Bacteria and viruses for example range from 0.2 to micron to 1 micron in size, while the pores in the Reverse Osmosis membrane are approximately 0.0001 to 0.0005 micron in size.  As purified fluid passes through the membrane, the unprocessed water(feed water) carries contaminants away to the drain, keeping the membrane clean. Reverse Osmosis is the same technology used by leading water bottling plants.

The main drawback to RO systems is the fact that they can require from 3 to 20 gallons of water for one gallon of purified water, a quality RO system being on the lower end of that range. It is for this reason that when comparing RO systems, the flow rate is an important consideration. The flow rate indicates the Gallons of Product Water produced per day(GPD). Since the flow rate of an RO system is directly influenced by water pressure(of the water supply its attached to), GPD specs are usually listed as GPD/Water Pressure. For example, a listing of 30/60 GPD would indicate an estimated 30 gallons of water produced per day, using the industry standard assumption of 60 psi water pressure. The efficiency of RO systems increases with greater water pressure and higher water temperature. Also worth noting when comparing RO systems is the size of its storage tank, as it limits how much filtered water can be produced at a time.

Another discriminating factor between Reverse Osmosis filters is the quality of its membrane system. The quality of the membrane is at the heart of any RO system, and a higher quality membrane will not only filter more efficiently but it will last longer and require less maintenance. The two common types of membranes are Thin Film Composite(TFC) and Cellulose Triacetate(CTA). TFC membranes are considerably more effective at filtering out contaminants than CTA membranes, but are also more susceptible to degradation from minerals and chemicals such as chlorine. For this reason, a carbon pre-filter is recommended for any system with this type of membrane.

What Contaminants does Reverse Osmosis Remove?

Reverse Osmosis systems are effective for removing all types of contaminants to some extent. More particularly, RO systems remove a high amount of sediment, arsenic, lead and heavy metals, flouride bacteria and viruses, nitrates, iron, total dissolved solids and radium. Ro systems also remove a high level of chlorine and to some extent VOCs and pesticides by way of a carbon pre-filter.

Other Considerations

One increasing concern of reverse osmosis is the fact that in addition to its efficient removal of contaminants, it also removes important minerals from water and in some cases may render the purified water acidic. Though RO generally does decrease the pH value of water, that water becoming acidic depends on the existing levels of CO2 gas  your water supply; as a predominant level of CO2 gas is what tends to make water acidic. We recommend that when purchasing an RO system you also purchase an accurate pH testing meter to be certain. Additionally, it is a good idea to include a mineral filter with your RO system, which will correct purified acidic water by adding essential minerals back to the water.

Pros

  • Effectively removes 90-99% of contaminants found in water
  • Is economical, costing 5 cents per gallon or less
  • Requires minimal maintenance

Cons

  • Removes natural trace minerals from water;  tends to decrease the ph balance of water potentially rendering it acidic(can be corrected with a pH increase or mineral filter)
  • May require 3 to 20 gallons of untreated water for one gallon of purified water
  • Daily production of filtered water is limited by flow rates and storage capacity

A Reverse Osmosis system ideal for:

  • persons complaining of bad tasting or smelling water
  • persons who live in an agricultural areas where pesticides and nitrates are a concern
  • persons who live near a nuclear power plant where radioactive contamination is a concern
  • well water filtration when combined with an ultraviolet system
  • any person who wants the most thorough filtration solution for their home or office
  • persons who buy plenty of bottled water and are seeking a more cost effective alternative
  • any person interested in filtering house water whether as a base component or primary filtration solution