|  | Public Health Safety | Environmental Health

Reverse Osmosis Vs. Carbon Filter

Unlike chemical treatments such as ozone and chlorine, both reverse osmosis and carbon filtration systems use a filter that water must pass through in order to be purified. These filters block out larger particles. They are often made out of particular materials or have a design that removes chemical agents that make water toxic or give it an unpleasant taste.

  1. Filtration Systems

    • Filtration systems are used to clean water of many different contaminants. They range from simple designs that remove large particles from irrigation water to highly sophisticated versions that strain enough contaminants from water to make it safe to drink. The primary method used by a filtration system is a type of membrane or screen that the water is made to passed through. These screens are designed to let only particles of a certain size through. Since water molecules are the smallest particles in the water itself, these can be let through while stopping larger particles.

    Reverse Osmosis

    • Reverse osmosis uses a membrane that allows water to pass through while holding back larger particles. There is usually a second stream of water used to carry away the contaminants from the membrane so they don't block the flow of water. These membranes can be made of different materials, but a flow of water is always required--in other words, the water must be subject to some sort of pressure, usually around 40 psi or greater. This process removes many different minerals and inorganic chemicals traveling with the water, but is especially good at blocking all bacteria and viruses.

    Carbon Filter

    • A carbon filter uses a panel or straining system of carbon blocks instead of a membrane to filter water. While a number of contaminants are removed simply because they are too large to make it through the carbon filter, the carbon itself acts upon the water, using chemical reactions to draw out various chemical and biological contaminants. They have little effect on minerals, but are used to remove both bacteria and contaminating agents like chlorine.

    Considerations for Reverse Osmosis

    • Reverse osmosis is a popular household filtration system because of its simplicity and cost effectiveness. While it is useful for cleaning water that has already been processed, RO systems can struggle when purifying untreated water, and usually a second system is required to make such water potable. The membrane RO systems use can degrade because of the corrosive agents it blocks, and it needs to be replaced occasionally. However, reverse osmosis excels at removing toxic metals and mineral-based contaminants that carbon filters struggle with.

    Considerations for Carbon Filters

    • Carbon filters are useful for removing odors and the leftover chemicals used in water purification, including chlorine. They can also remove harmful contaminants that reverse osmosis does not deal with as effectively, such as volatile organic compounds. Certain users prefer carbon filters because they leave in natural minerals, but if the water is contaminated by nitrates or fluoride, then an RO system needs to be used to remove them.

Environmental Health - Related Articles