Ion exchange is a popular method for reducing the potential for mineral scale formation on the membrane surface. Ion exchange softening uses sodium to replace scale-forming ions such as calcium, magnesium, barium, strontium, iron, and aluminum to prevent damage to the membrane elements.. The sodium forms very soluble salts, which are readily rejected by the Reverse Osmosis System and do not readily form mineral scales on the membrane surface. A sodium-cycle softener is regenerated with sodium chloride brine. The spent regenerant, along with the softener rinse water, must be discharged to waste. It is because of this that ion exchange is recommended for applications that have high metal contents in the treated water.

n one word: analysis. Every source of water is different, and you never know what's in your water until you have it analyzed. The water analysis, LSI, SDI, or CFI values are used to determine the precise pretreatment requirements for a particular  RO System. Since water supplies vary considerably from one location to another, each pretreatment requirement will be different. On average, most Reverse Osmosis Systems need an antiscalant injector or water softener to prevent damage to the membrane.

If you work with an RO, you understand that the feed water must be preconditioned to protect the membranes from fouling and premature failure. An RO membrane functions much like a cross flow filter. The membrane is constructed of a porous material that allows water to pass through the membrane, but rejects up to 99% of the dissolved solids at the membrane surface. The dissolved salts are concentrated in the Reverse Osmosis reject water, or brine stream, where they are discharge to waste.

As the RO System continues to operate, the dissolved and suspended solids in the feed water tend to accumulate along the membrane surface. If these solids are allowed to build up, they eventually restrict the passage of water through the membranes, resulting in a loss of throughput. (The throughput capacity of the membranes is commonly referred to as the flux rate, and is measured in gallons per square foot of membranes surface area per day.)

Early in the development of membranes systems, little was known about which impurities in the Reverse Osmosis feed water are likely to cause fouling and a corresponding reduction in flux. Today, many of these troublesome impurity treatments have been identified, and preventive treatments have been devised that greatly reduce membranes fouling, thus prolonging the life of the RO plant.

Reverse Osmosis is an ideal water treatment solution in most types of water. Generally speaking, all major water sources from a treatment standpoint can be broken down into three major categories: tap water, also known as municipal sources, groundwater, which includes brackish water, and saltwater. The biggest distinction between these three types is the Total Dissolved Solids (TDS) content of each type. As a rule of thumb, the American Health Association requires that drinking water is under 1,000 PPM TDS.
Tap water typically comes through a pre-existing infrastructure like city pipes or a damming system. Reverse osmosis is often used in a tap water environment to reduce hardness, or the debris deposited in water from traveling in metal pipes. Total dissolved solids is often a target of water purification in tap water systems. This type of Reverse Osmosis Systems are ideal in places like power plants, pharmaceuticals, laboratories, and hospitals, where an extreme purity of water is crucial to the industry. Tap water typically has a TDS of under 1,000 PPM.
Underground reservoirs of water are often brackish or highly brackish, meaning they contain large volumes of salt, but not enough to be considered salt water. Groundwater reverse osmosis is very common, and one of the best uses of a Reverse Osmosis System to date. Groundwater is most often purified for the agriculture industry, the mining industry, and for residential use. Groundwater is also a prized target of the bottling industry, because the unique mineral combinations often have an appealing taste. Brackish water usually has a TDS of 5,000 PPM or less, but can come in concentrations of up to 12,000 PPM.
Salt water reverse osmosis (sometimes referred to simply as desalination) is the turning of saltwater into drinking water. Ocean water has up to 45,000 PPM TDS. Typically, for environmental reasons, a bore hole is dug in the ocean for this kind of reverse osmosis, but an open intake is more cost effective. The biggest uses of desalination come in providing water in areas that lack a regular supply of fresh water.

Reverse Osmosis is an ideal water treatment solution in most types of water. Generally speaking, all major water sources from a treatment standpoint can be broken down into three major categories: tap water, also known as municipal sources, groundwater, which includes brackish water, and saltwater. The biggest distinction between these three types is the Total Dissolved Solids (TDS) content of each type. As a rule of thumb, the American Health Association requires that drinking water is under 1,000 PPM TDS.
Tap water typically comes through a pre-existing infrastructure like city pipes or a damming system. Reverse osmosis is often used in a tap water environment to reduce hardness, or the debris deposited in water from traveling in metal pipes. Total dissolved solids is often a target of water purification in tap water systems. This type of Reverse Osmosis Systems are ideal in places like power plants, pharmaceuticals, laboratories, and hospitals, where an extreme purity of water is crucial to the industry. Tap water typically has a TDS of under 1,000 PPM.
Underground reservoirs of water are often brackish or highly brackish, meaning they contain large volumes of salt, but not enough to be considered salt water. Groundwater reverse osmosis is very common, and one of the best uses of a Reverse Osmosis System to date. Groundwater is most often purified for the agriculture industry, the mining industry, and for residential use. Groundwater is also a prized target of the bottling industry, because the unique mineral combinations often have an appealing taste. Brackish water usually has a TDS of 5,000 PPM or less, but can come in concentrations of up to 12,000 PPM.
Salt water reverse osmosis (sometimes referred to simply as desalination) is the turning of saltwater into drinking water. Ocean water has up to 45,000 PPM TDS. Typically, for environmental reasons, a bore hole is dug in the ocean for this kind of reverse osmosis, but an open intake is more cost effective. The biggest uses of desalination come in providing water in areas that lack a regular supply of fresh water.

• Pretreatment of Boilers
• Food and Beverage Services
• Industrial wastewater purification
• DI water pretreatment
• Hotels and Resorts
• Ice making
• Car washes
• Pure ethanol
• Dairy industry
• Maple syrup
• Pharmaceuticals
• Water Bottling
• Hospitals
• Agriculture
• Humidification

A Reverse Osmosis System is built of five basic parts:
1) Pressure Vessels & Membranes
Obviously, a Reverse Osmosis System wouldn't get very far without membrane elements. The proteins that make up membrane elements vary depending on the kind of intake water and ending clarity. There are membrane elements for brackish water, seawater, hospital-grade disinfection, and membranes designed to remove specific contaminants to name a few. If there is a water treatment need, you can be sure there is certainly a membrane element for the job. The size of the task (municipal, commercial, or industrial) will determine the size and number of membranes in a system. There can be anywhere from a single two and a half inch membrane (like in an under-sink Reverse Osmosis System) to hundreds of eight inch membranes all working together (a typical reverse osmosis plant).
2) Reverse Osmosis Skid
The best way make your Reverse Osmosis system as durable as possible is with a powder coated, carbon steel frame to mount all of your components on. It's resistant to the elements, designed for the heavy vibration of high-pressure pumps, and  mounts to the ground to ensure that it will last a lifetime.
3) Cartridge Filter
Most Reverse Osmosis Systems come with a cartridge filter to ensure that no particles large enough to damage the membranes come anywhere near them. This cartridge is usually a five micron spun polypropylene filter, but can vary upon request. The cartridge comes in a durable casing that can handle the pressure from the main feed or booster pumps.
4) Reverse Osmosis High Pressure Pump
Without a high-grade pump, the rejection rate for a Reverse Osmosis System isn't viable in most commercial or industrial settings. It is vital to the system to ensure that the pump is matched to the membrane quantity and size appropriately. Usually, the higher the horsepower on the intake pump, the better the rejection and recovery rates of permeate.
5) Control Panel
Lastly, the Reverse Osmosis System has to be controlled by a human operator. At Pure Aqua, we use advanced PLCs or a solid-state microprocessor depending on how advanced the controls need to be. The controls can also be used to manage multiple systems simultaneously, effectively making a one-man water production plant.
Reverse Osmosis Systems can have a number of other components built onto or into them as extra components as well. The entire skid can be built into a containerized system, for example, so your Desalination by RO System is always on the go. There are a number of supplemental skids that can be attached to an RO System as well, for tasks like membrane cleaning, pretreatment, chemical dosing, and a number of other jobs as necessary.

Now that we know how Reverse Osmosis as a process works, let's take that and apply it to a real, working TWRO or BWRO System. If it only needed the membranes and a pump, it certainly wouldn't be so big, right?

A) Pre-Chlorination Dosing System

If the feed water contains traces of heavy metals or contaminated, it is high recommended to dose some chlorine to change the dissolved heavy metals to physical form, the media filter will be able to filter most of it.

B) Raw Water Storage Tank

Although some RO Systems can draw water right out of a well or pipe feed, most systems start with a large tank that stores the contaminated water. Not having enough feed water can damage a pump, so having a large storage tank for your intake water is an easy way to make sure your pump lasts for as long as possible.

C) Feed Water Pump

A commercial or industrial pump provides the initial pressure for the Treatment System. This motor usually provides enough water pressure to get through any pretreatment as well as the RO membranes, but if it doesn't a booster pump may be necessary farther down the line.

D) Multi-Layer or Media Filter

As much as we hate to admit it, there are some things that membranes can't purify. Nitrates, a common contaminant found in fertilizers and animal waste, are a good example of particles that dissolve too well in water for reverse osmosis to catch them. Things like foul odor and taste usually aren't prevented by reverse osmosis, either. A Multi-Layer filter can be filled with media that specifically targets the things your RO System can't catch. If you need to eliminate these contaminants, a Multi-Layer Filter is a must. An example of MMF or multi media filters is our MF-1000 Series.

E) Activated Carbon Filter

Activated carbon filters are good solution to reduce organic, bad taste, smell and chlorine from the water.

F) Automatic Water Softener

Automatic water softeners are designed to remove water hardness, calcium and magnesium ions, for small RO systems, we usually recommend water softeners instead of the antiscalant chemical dosing. 

G) Antiscalant Chemical Dosing System

For larger RO systems, we use antiscalant dosing systems to dose our PA0100 antiscalant RO chemical, which helps in preventing membranes fouling. Please refer to our chemical dosing pumps series for more information CDS-Series.

H) Reverse Osmosis System

We finally have our Reverse Osmosis System. If a booster pump is necessary, it will typically be just before this step. The Reverse Osmosis System can produce up to one million gallons of product water a day from a steady intake, as well as a sizable amount of waste. Usually the waste water can be dumped down the drain, but check with your local water authorities in case it needs to be handled with care.

I) Product Water Storage Tank

The permeate from the RO purification system will usually go to a large tank, where it is held for use. If it didn't, the system would need to be running in order to have access to fresh water, which can be inconvenient. Sometimes, an RO treatment System pumps water directly into a well or aquifer for recharging instead of being used in many of the normal industries or applications it is used in.

J) Post-Chlorination Dosing System

If the permeate water is intended to be stored for more than one day, it is highly recommended to dose some chlorine to maintain clean and non contaminated water.

K) Product Water Pump (Re-pressurization)

This pump repressurizes the permeate water to the point of use ends. This is selected based on the overall travelling distance and required head. This pump must be selected in stainless steel to prevent any contamination to the permeate water.

L) Product Water UV Sterilizer

The UV sterilizer is placed after the storage tank, and as a final disinfection device. Most of the time, we either use post chlorination as a disinfectant agent, or ultraviolet sterilization.