How Does Reverse Osmosis Work? The Water Filtration Process Explained
Reverse osmosis (RO) is one of the most effective technologies for removing contaminants from water and producing clean, safe drinking water. In areas with brackish or contaminated water sources, RO has become an essential process for providing potable water.
So how does reverse osmosis work exactly? Let's take a look at the stages of the reverse osmosis process and how it filters water on a molecular level.
Overview of Reverse Osmosis
Reverse osmosis uses a semi-permeable membrane and pressure to separate pure water molecules from dissolved salts, metals, minerals, bacteria, and other contaminants. It works by pushing water through the RO membrane, which acts as an extremely fine filter that only allows water molecules to pass through while blocking larger molecules and ions.
There are 5 basic stages in a reverse osmosis system:
Pre-Filtration - Water passes through sediment filters to remove suspended particles like silt, dirt, and rust.
Pressurization - The water is pressurized to 100-400 psi using a pump to force it through the RO membrane.
Reverse Osmosis Membrane - Under pressure, the water diffuses through the semi-permeable membrane while contaminants are flushed to the drain.
Post-Filtration - The filtered water may pass through additional carbon filters to improve taste.
Storage - The purified water is stored in a holding tank before going to the faucet.
Now let's look at what's happening on a molecular level as the water passes through the reverse osmosis membrane.
The Reverse Osmosis Membrane
The reverse osmosis membrane is the heart of the system. It has tiny pores that are sized to block dissolved salts and minerals while allowing water molecules to pass through.
An RO membrane has a pore size of 0.0001 microns. To put that in perspective, a human hair is about 50 microns wide, making the RO pores 500 times smaller! Contaminants and particles larger than water molecules simply cannot fit through the membrane's microscopic pores.
As pressurized water flows across the membrane surface, pure H2O diffuses through the semipermeable barrier. Larger contaminants, on the other hand, are swept along the membrane to drain out as waste.
Some key points about the RO membrane filtration process:
The membrane pores allow the passage of water molecules while excluding dissolved salts, metals, minerals, bacteria, and organics.
Water permeability is a function of the water pressure, membrane surface area and temperature. More pressure = faster diffusion.
Typical salt rejection is 96-99% for seawater and 90-98% for brackish water, producing permeate of less than 10 ppm TDS.
Purified water recovery rates average 15-50% for seawater and 40-85% for brackish water sources.
Pretreatment is critical to maintain membrane performance and prevent fouling or scale buildup on the membrane surface.
Reverse Osmosis in Tampa Bay, Florida
In the Tampa Bay area, the source water is groundwater from the Floridan Aquifer System. While quite clean, it still contains dissolved minerals including calcium, magnesium, iron, chlorides and sulfates which make it "hard" water. The local groundwater has a total dissolved solids (TDS) content of 500-1000 ppm.
Reverse osmosis is an effective way to desalinate and soften well water for residential and commercial use in Tampa. RO systems reduce scaling and staining fixtures while also improving the taste, smell, and clarity of the water.
Some key water quality benefits of RO for Tampa Bay include:
Removes up to 99% of total dissolved solids and hardness minerals
Reduces chlorides, sulfates, iron, manganese and hydrogen sulfide
Lowers TDS below 10 ppm for pure, mineral-free water
Eliminates unpleasant odors and tastes
Filters out bacteria and organic contaminants
Protects plumbing from scale buildup and corrosion
By removing dissolved contaminants through reverse osmosis, Tampa Bay residents can enjoy safer, better tasting water from their taps, showers and appliances.
Reverse Osmosis System Design
There are many different reverse osmosis system configurations depending on the feed water quality, desired product water quality and production capacity. Here are the key components in a typical residential RO unit:
Raw water inlet - Well or city water supply.
Sediment prefilter - Removes sediment down to 5 microns. Protects membranes.
Carbon prefilter - Removes chlorine and organics that can foul membranes.
Pressurization pump - Delivers feed water pressure of 80-125 psi to the membranes.
Membrane array - Heart of the system. Polyamide thin-film composite membranes remove contaminants.
Flow restrictor - Maintains pressure across membrane surface for separation.
Post-filter - Polishes water with activated carbon to remove tastes and odors.
Storage tank - Holds the purified water ready for use. Tank size depends on water demand.
Dispensing faucet - Delivers RO water on demand. Often has separate dispenser for filtered water.
Larger commercial and industrial RO systems may also utilize multi-stage pretreatment, booster pumps, multi-element membrane arrays, and disinfection to handle higher contaminant loads and production rates.
Proper system design is critical to producing sufficient quantities of permeate water at the desired quality. Aqua-Wise Water Treatment Solutions employs top engineers to customize reverse osmosis and other treatment systems to meet the unique needs of Tampa Bay area businesses and homes.
Reverse Osmosis Benefits
Reverse osmosis water purification offers numerous benefits for both residential and commercial applications:
Produces high quality water for drinking, cooking, brewing, etc.
Protects plumbing and fixtures from scale buildup and corrosion.
Improves the taste and smell of water by removing chlorine and contaminants.
Treats hard water to reduce soap scum in sinks, showers and washing machines.
Removes microscopic particulates down to 0.0001 microns in size.
Eliminates bacteria and microorganisms to disinfect water.
Can desalinate brackish groundwater and seawater for potable use.
Environmentally friendly process with minimal chemical use.
Automated operation with relatively low maintenance.
Can process thousands to millions of gallons per day.
Reverse osmosis gives both homes and businesses access to fresh, pure water for drinking, bathing, cleaning and food production. The advanced filtration technology of RO water treatment solves stubborn water quality issues efficiently and sustainably.
Residential Reverse Osmosis Systems
For homes with hard well water or unpleasant city water, a point-of-use reverse osmosis system under the sink can provide purified water for drinking and cooking.
AquaRevive residential RO systems from Aqua-Wise Water Treatment Solutions reduce TDS by up to 99% to produce mineral-free water for better tasting coffee, tea, juices and recipes. Their thorough 5-stage filtration rivals bottled water quality at a fraction of the cost.
Key features include:
High quality Aqua-Wise RO membrane for optimal contaminant reduction
Quick connect fittings for fast installation under your sink.
Modern electronic faucet indicates when filters need replacement.
Smart digital water quality TDS meter.
Built-in leak detection shutoff valve.
Delivers 8-12 gallons per day, ideal for most homes.
Designed for years of reliable performance.
With an AquaRevive reverse osmosis system, Tampa Bay homeowners can bypass bottled water delivery and get unlimited purified water on demand. Discover why it's one of the most popular water filtration solutions for the area.
Whole House Reverse Osmosis Systems
In addition to drinking water RO units, larger whole house systems are available to treat all the water entering a home or business.
AquaBlue whole house RO systems from Aqua-Wise Water Treatment Solutions use multiple membrane housings piped in parallel to produce permeate water at flow rates from 15-300+ gallons per minute, depending on the model.
Benefits of whole house reverse osmosis include:
Removes scale-causing hardness for soft water throughout your building.
Eliminates odors and discoloration issues.
Filters chlorine and sediment that damages pipes and fixtures.
Improves water pressure by preventing mineral buildup in plumbing.
Water tastes fresh and clean from every faucet and shower.
Protects appliances like water heaters, ice makers and coffee brewers.
Reduces spotting on glassware, dishes, sinks, and fixtures.
Extends the life of water-using equipment by removing corrosive contaminants.
With a whole house system, all the water your residence or facility consumes can be purified for greater convenience and reliability.
Commercial and Industrial Reverse Osmosis Systems
For commercial sites like hotels, schools, hospitals, and office buildings, AquaPurityTM industrial reverse osmosis units from Aqua-Wise Water Treatment Solutions provide cost-effective, high purity water for guest rooms, kitchens, cooling towers, boilers and more.
AquaPurityTM systems are designed for efficient operation and reliability even under heavy use. With production capacity from 500 to over 1 million gallons per day, they can readily handle the needs of manufacturing plants, food processors, high-rise towers, drinking water systems, and other businesses.
Some applications include:
Membrane filtration benefits:
High purity water for pharmaceutical, cosmetic and food manufacturing.
Sanitary water for health care facilities and labs.
Low solids water for autoclaves, humidifiers and auto scrubbers.
Pre-treatment for deionization and distillation polishing.
Removal of microbial contaminants like Cryptosporidium and Giardia.
Purified drinking water from brackish or seawater.
Industrial process water from impaired sources.
Wastewater recycling and reuse.
Produced water treatment for oil and gas operations.
With integrated pretreatment, disinfection, controls, and 24/7 remote monitoring, AquaPurityTM systems run with minimal supervision and maintenance. Aqua-Wise's expert engineers handle everything from design to installation to service and repairs.
Choose Aqua-Wise Water for Your RO System
Headquartered in Tampa Bay, Aqua-Wise Water Treatment Solutions has over 25 years of experience providing reverse osmosis and other water purification systems across Florida. Their dedicated team handles both residential and commercial projects.
Reverse osmosis services include:
Custom engineering and design
City and well water testing
Installation of under sink, whole house and commercial RO systems
Maintenance contracts and membrane cleaning/replacements
Upgrades of existing reverse osmosis units
Troubleshooting and repairs
System rentals for temporary purer water needs
Aqua-Wise utilizes top brands like Aqua-Wise, AquaCarbonGuard Catalytic Carbon Filter and HydroClear Ozone Generator for Heavy Metals and Bacteria to build RO treatment solutions that solve any water problem. With innovative products and expert service, they make it easy and affordable to enjoy unlimited clean, healthy water.
Discover how a new reverse osmosis system can restore your water quality. Contact Aqua-Wise Water Treatment Solutions at (727) 236-7161 for a free consultation and quote for your residential or commercial property. Or schedule your free water test online to get started.