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Water Filtration Wars: Reverse Osmosis vs. Deionized Water Filtration

Water Filtration Wars: Reverse Osmosis vs. Deionized Water Filtration

Mdeionized-waterany people hear about trendy things like reverse osmosis water and deionization, and this brings up questions about whether they should be getting in on the trendy water filtration systems that are sweeping household faucets. So before you decide which (if either) system is right for you, here's a bit of a primer about RO and DI systems, and the pros and cons of each.

Reverse Osmosis: The Basics

Both reverse osmosis and deionization are forms of water filtration that remove particles and contaminants from water. The RO process works by forcing water through a semipermeable membrane, thereby removing up to 99 percent of the impurities in water, such as salt, dirt, arsenic, radium, and other chemicals.

Multi-Stage System

A full RO filtration process involves different sets of filters, including a:

  • Pre-filter that’s designed to remove sediment like dirt and silt
  • Carbon filter that eliminates chlorine, odors, and tastes
  • Reverse osmosis membrane that filters the water of contaminants

How it Works

Osmosis is a naturally occurring process whereby molecules from an area of low saline concentration migrate through a semipermeable membrane to an area of higher saline concentration. Reverse osmosis, on the other hand, uses energy to power the process, and the membrane only lets water pass through instead of salt and contaminants.

Essentials of Deionized Water

Whereas the RO process uses a type of filtration to purify water, deionization isn't as much a filtration procreverse-osmosisess as it is a chemical reaction, wherein hydrogen and hydroxyl molecules are exchanged for contaminants and other ions, such as:

  • Copper
  • Sodium
  • Sulfate
  • Magnesium
  • Calcium
  • Ionized salt

DI water is also an on-demand system, so it converts contaminated water to purified water when necessary, rather than purifying batches and storing them for later use.

Pros of RO and DI Filtration

The main benefit of both reverse osmosis and deionized water is that they both remove unhealthy contaminants from water, such as lead, salt, mercury, and asbestos. And since the DI process also adds hydrogen to water, it acts as a water softener as well.

Since both RO and DI remove contaminants and deposits from water, both processes yield high-purity water that’s perfect for cleaning and industrial uses. Deionized water, in particular, is ideal for aquariums, labs, and manufacturing processes.

Cons of RO and DI Filtration

Neither reverse osmosis nor deionized water is free of all contaminants. RO on its own, for instance, cannot remove chlorine from drinking water without the added help of a carbon filter. And the RO process also fails to remove some pesticides, VOCs, and solvents. Similarly, DI is not designed to remove bacteria and particulates, and the process won’t clean water of these contaminants without additional filters.

Both RO anwater-filter-installationd DI water are devoid of minerals and elements that the human body needs to survive, such as calcium and magnesium. Therefore, drinking these types of demineralized waters exclusively is not recommended.

Moreover, deionized water is also notorious for stripping metals and possibly dangerous chemicals from pipes and storage materials, meaning drinking this type of water could lead to the consumption of dangerous contaminants anyway.

For people considering a water filtration system for their drinking water, both reverse osmosis and deionization systems will remove a great deal of contaminants from water.

However, some of the minerals that get removed from the water are actually necessary for human life, meaning both RO and DI water are not necessarily safe solutions for drinking water. But if you need purified water for either cleaning, manufacturing, or other purposes, then DI water is probably the purest water you can get.

For more information about filtration systems, or for help with seasonal or emergency plumbing repairs in Cobourg, ON, call Guardian Plumbing today at (289) 251-1626.


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