Reverse osmosis (RO) water filtration has been around since the late 1950s, but with the continuous increase in water pollution, it’s been gaining popularity recently. As one of the most efficient filtration methods available, RO can remove the majority of common water contaminants.
Reverse osmosis is also ideal for homes in the Sarasota and Bradenton area. Our proximity to the ocean means that our water sometimes takes on a salty taste. Reverse osmosis removes the salt, leaving you with fresher-tasting water.
Osmosis is the movement of liquid, such as water, with a low concentration of soluble substances like salt through a semi-permeable membrane into a place with a higher concentration of soluble substances. Simply put, osmosis is gradual absorption.
Applying pressure to the concentrated side reverses the osmosis process. In reverse osmosis, the liquid flows out of the concentrated solution instead of into it.
A residential reverse osmosis filtration system relies on your home’s normal water pressure to push your water through a filtration membrane. This membrane stops most contaminants and lets through water molecules.
The process occurs in four basic steps:
- Pre-filtration: As water enters the RO system, it first runs through one or more pre-filters, usually including a sediment filter and carbon filter. These trap larger particles as well as chemical contaminants that could harm the filtration membrane.
- Reverse osmosis filtration: The water then flows to an RO filtration membrane. Your household water pressure pushes the water against the membrane, slowly forcing water molecules through.
- Wastewater drainage: Most contaminants in the water can’t pass through the membrane. These are discharged in wastewater through a drain line.
- Storage and post-filtration: Depending on your system type, the purified water may flow into a storage tank. When you turn on the faucet, stored water flows through a post-filter, usually a carbon filter, that removes any lingering impurities.
The quality of the filtration membrane largely determines the system’s effectiveness. The two main membrane materials used in residential RO systems are polyamide thin film composite (TFC) and cellulose. TFC membranes are the most popular because they’re less expensive to manufacture than cellulose membranes, yet they provide better filtration. Because this material is susceptible to chlorine damage, the system must include a carbon pre-filter to ensure only chlorine-free water reaches the membrane.
What reverse osmosis removes
A reverse osmosis membrane removes most contaminants larger than .001 microns. That means almost every contaminant larger than a water molecule will be filtered out.
The process can remove 60 to 98 percent of many common contaminants, including municipal-additive fluoride, nitrates, copper and lead. It’s the only type of filtration that can remove arsenic. Naturally occurring minerals, including sodium, calcium, magnesium, iron and manganese, will also be filtered out.
On the down side, RO doesn’t remove harmful volatile organic chemicals (VOCs), chlorine or the traces of pharmaceuticals, pesticides and herbicides found in Florida’s water supply. That’s why these systems include carbon filters, which do remove many of these contaminants.
The right system for your needs
Although all reverse osmosis systems contain the same essential components and work the same way, systems are available in three main sizes to meet differing needs.
- Whole-house system: These large systems are typically reserved for homes supplied by well water that’s unusually contaminated. Their size means that the main components are usually located in the garage or basement.
- Under-sink system: This system is sufficient for most homes supplied with average-quality municipal or well water. The system is connected to the water supply under your sink and contains three to five filtration stages. The purified water is held in a storage tank with a separate faucet installed to draw water from the tank.
- Countertop system: These systems are connected directly to your sink faucet with a feed line. Turn on the faucet and the water flows into the system for filtration. Despite their small size, countertop systems use the same three to five filtration stages as larger systems and can produce 100 gallons of pure water or more per day.
The type of filtration system that’s best for your home depends on a number of factors, including your water quality and how much water you use daily. A professional water quality test should be your first step in choosing a filtration system.
If you’re considering adding a reverse osmosis water purification system to your home or you’d like your water quality professionally assessed, contact us at Aqua Plumbing & Air. We offer reliable services to meet the plumbing, heating and air conditioning needs of homeowners around the Sarasota and Bradenton area.