FAQs About Reverse Osmosis Drinking Water Systems

Yes—in most case we can connect directly to your refrigerator. Connecting the system will extend the life of your ice maker and make clearer, great tasting ice. You can turn your fridge into a Culligan "Water and Ice Machine".

Yes—The system uses multiple processes including Reverse Osmosis to make great tasting, low sodium drinking water. Reverse Osmosis removes about 97% of the TDS (Total Dissolved Solids) from most tap water. Read the labels on bottled water and you will discover Reverse Osmosis is the same process used by most bottlers—so in effect—you really are getting "bottled water without the bottle"!

Yes—We recommend annual service approximately. Our service technician will test your water each time, replace necessary filters and sanitize the system.

Reverse osmosis, also known as hyperfiltration, is the finest filtration known. This process will allow the removal of particles as small as dissolved individual ions from a solution. Reverse osmosis is used to purify water and remove ions and dissolved organic molecules. It can be used to purify fluids such as ethanol and glycol, which will pass through the reverse osmosis membrane, while rejecting other ions and contaminants from passing. The most common use for reverse osmosis is in purifying water. It is used to produce water that meets the most demanding specifications that are currently in place.

Reverse osmosis uses a membrane that is semi-permeable, allowing the fluid that is being purified to pass through it, while rejecting the contaminants that remain. Most reverse osmosis technology uses a process known as crossflow to allow the membrane to continually clean itself. As some of the fluid passes through the membrane the rest continues downstream, sweeping the rejected species away from the membrane, in a concentrated brine reject water. The process of reverse osmosis requires a driving force to push the fluid through the membrane, and the most common force is pressure from a pump. The higher the pressure, the larger the driving force. As the concentration of the fluid being rejected increases, the driving force required to continue concentrating the fluid increases.

Reverse osmosis is capable of rejecting bacteria, salts, sugars, proteins, particles, dyes, and other constituents that have a molecular weight of greater than 150-250 daltons. The separation of ions with reverse osmosis is aided by charged particles. This means that dissolved ions that carry a charge, such as salts, are more likely to be rejected by the membrane than those that are not charged, such as organics. The larger the charge and the larger the particle, the more likely it will be rejected.

A typical system consists of:

• One or more pre-filters to remove silt, iron, chlorine or other particulate matter.
• A membrane to remove raw water contaminates.
• A pressure sensitive hydraulic on/off pressure valve to send pre-filtered water to the membrane to make treated water for storage.
• A small storage tank for treated water.
• May include a post-filter to polish stored water and to maximize its taste just prior to consumption.

Permeate flux and salt rejection are the key performance parameters of the reverse osmosis process. They are mainly influenced by variable parameters such as; pressure, temperature, recovery, and feed water salt concentration.

Water Pressure—Increased feed water pressure will increase permeate flux and decrease the permeate TDS. With excessive pressure the membrane may become deformed or compacted and a decrease in product flow will result.

Temperature—Increased temperature will increase permeate flux, which increases salt passage. It is also important to note that every unit is rated for a product flow temperature of 77°F (25°C). With a temperature decrease, the product flow will decrease. On average the membranes lose about 2% production for every degree below 77°F.

Recovery—The recovery is the ratio of the permeate flow to the feed flow. When recovery is increased, the permeate flux will decrease and the salt passage will increase.

Feed water Concentration—Increased TDS or salt concentrations will decrease permeate flux and increase salt passage. This can also lead to surface coating or fouling by the salt.

A standard RO System has a hydraulic on/off pressure valve which is controlled by source water pressure to send pre-filtered water to the membrane to make water for storage.

When water pressure in the storage tank builds up to 90% of the incoming line pressure, the standard hydraulic on/off pressure valve shuts off the flow of water to the system, stopping treated water production. When you open the RO faucet, system pressure drops as treated water exits the tank. The standard hydraulic on/off pressure valve turns on when the tank pressure is less than the source water pressure and treated water is produced through the RO system. The cycle repeats itself.