Reverse Osmosis

What Is Reverse Osmosis

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Much of man’s technological innovations today have been borrowed mostly from nature. One of them is a very important process called “reverse osmosis”. It is the opposite of the natural process called osmosis. What, then, is reverse osmosis and what does it do?

As man moves towards progress, water and the other natural resources of the world have become polluted and unsafe for use. Reverse osmosis is one of today’s important methods for processing water to make it clean and safe for use.

Osmosis and reverse osmosis

First, what is osmosis? Osmosis is a natural process where water of different concentrations and separated by a semi-permeable membrane will cause the water from the diluted solution to move into the more concentrated solution.

This is because this semi-permeable membrane (the osmotic membrane) allows only water to pass through and restricts most other elements.

In reverse osmosis, the opposite happens. Applying pressure, water from the more concentrated solution is forced out through the membrane into another container, in effect straining it from impurities. This is the process commonly used today to purify water.

The basis of the whole system is the semi-permeable membrane that acts as a strainer. This membrane is permeable only to water molecules. As the concentrated water (water with dissolved and solid particles of minerals, salts, etc.) is forced through the membrane, only water molecules can pass through the pores.

The most common artificial membranes used today are made from cellulose acetate, cellulose triacetate or aromatic polyamide resins. These are tough to withstand the high water pressures and can last for about two or three years before replacement.

These impurities that cannot pass through the membrane are composed of various mineral salts, heavy metals, other matter particulates, organic molecules, some bacteria, and even some viruses. These are rejected by the membrane based on their molecular or atomic weights.

The membrane removes these salts and other dissolved mineral elements, as well as other impurities like sugar, proteins, dyes, nitrates, and pesticides. All things considered, this improves the taste, color and other natural properties of water.

The process is also known to remove particles as small as ions or charged atoms. Today, it is also used to purify other fluids such as ethanol and glycol which passes through a membrane that rejects other ions and contaminants from passing through.

The most common force used in the procedure is pressure from pumps. The higher the pressure, the bigger the driving force.

In the old mechanical filter systems such as the standard carbon filtration, total dissolved solids (called TDS) cannot be removed. High concentration of TDS usually gives the water an objectionable taste, causes scale buildup in utensils and equipments, and causes poor quality in beverages and ice-making.

According to studies, reverse osmosis removes 95% to 99% of the total dissolved solids in contaminated water. Right now, it is considered one of the best technologies in producing clean water free from TDS and other contaminants and is therefore safe for human consumption.

Some problems

There are some problems, of course, that must be solved while using this system. The amount of contaminants, the size and type of equipment used and the amount of pressure are some factors that contribute to the buildup of materials on the membrane, making it ineffective.

Moreover, chlorine in the water causes damage to some membranes. To prevent this, manufacturers install a carbon pre-filter to reduce the chlorine, as well as sediment pre-filters to prevent other fine particles to clog the membrane. Which, of course, are added costs.

On the whole, however, reverse osmosis is the leading water filtration system used by homes and many industries. So far, it had justified its costs and surpasses expectations from health authorities with regards to safety and cleanliness.

Understanding Reverse Osmosis

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You probably have heard reverse process as a water purifying process for many times now. You should know that it is a very important and very effective way of purifying water. In general, the process is used not just in residential and commercial water filtration.

Reverse osmosis is the top method used when desalinating seawater so it could be converted into a form that could be commercially drank and consumed by people. In many industries, the process is also used when purifying liquids, wherein water serves as the undesirable impurity that should be taken out (like in the case of ethanol).

To better understand the process, it would be appropriate to review osmosis. Back in the days when you were studying general science, you have discovered that there is diffusion to balance things out. Diffusion happens in the air, while osmosis on water or liquid. The idea is that through osmosis, molecules in water would move to balance two water bodies with different concentration.

For example, if a cell lack concentration of a substance that is abundant in its external, osmosis would work so that molecules from the outside would pass through cell’s semi-permeable membrane to enter the cell. The process goes on until concentration on both the outside and inside of the cell is equal.

Through the years, science has also discovered that the natural process of osmosis could be effectively slowed, stopped, prevented, and even reversed. Reversal of the osmosis process could be possible only if there would be adequate pressure to be applied to the involved membrane coming from the more concentrated side. In some instances, the reverse osmosis is referred to or described as a process of filtration, especially when it is used to purify water.

There is a need to force the solvent in a region where there is higher concentration into getting through the semi-permeable membrane so that it could transfer without much hassle into the region of lower solute concentration. This force is often called osmotic pressure. Membranes used have denser barrier layer to facilitate better separation. Usually, such membranes and designed specifically to allow passage of water only and prevent passing of solutes like in the case of salt ions in seawater desalination. In general, much higher pressure is applied when doing reverse osmosis to purify salt water than used to purify brackish or fresh water.

Reverse osmosis as a water purification process has gotten so popular that many households these days are investing in setups and devices to facilitate the process. Household reverse osmosis devices or units are using much water due to low back pressure.

Though such systems are economical and are convenient, experts assert that they are not as effective as intended. Water recovered is only at 5% to 15%, so the household may need to use more water to be able to fill the desired and required amount. Many people could attest that such devices are yet to be improved to bolster practicality for household use.

The process of reverse osmosis is very promising. But scientists and investors are still underway to discover and develop more effective and efficient ways to prompt and facilitate the process. In the end, this could be a hope to be used and applied in areas where pure and safe drinking water is much of a problem.

The Uses Of Reverse Osmosis

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If necessity is the mother of invention, then, in essence, reverse osmosis is truly a daughter of necessity. It was initially developed by the U.S. Navy to produce drinking water through desalination (getting the salt out of sea water) for submarine crews. Today, the uses of reverse osmosis have branched out to other areas, including home use and uses in other industries.

Basically, reverse osmosis (often referred to as R/O) is a filtration technology that forces water into passing through a semi-porous membrane that filters out unwanted chemicals and solids. In desalination, the water is rid of salt and can be drunk.

In the version adapted for home use, R/O units are fitted with carbon and other mechanical filtration devices to produce highly purified water that tastes good.

The R/O process

Scientists essentially copied what Nature had been doing all the time, with a little modification by way of reversing the process. In Nature, osmosis is the natural process of water seeping through a semi-porous membrane into a solution that is of higher consistency.

In R/O, scientists force higher consistency water solutions (sea water, other water with dissolved minerals and other solids, etc.) through a membrane that strains out all these other non-essentials to produce pure water.

The goal is to provide fresh recycled water for human consumption, especially in progressive and highly-industrialized areas where the use of resources is excessive. Water is one vital resource that’s precariously getting short.

The R/O process is also used in other areas of industry. It is used to squeeze out water from ethanol and glycol so that these can be purified and used for fuel. In others, food concentrates (tomato juice, apple juice) are thickened by squeezing out the extra water.

Still in other industries, the process is also used to harvest dissolved metals (copper, nickel, chromium) and other particulates in liquids for use as metals plating or in the finishing processes.

Development

The research for R/O process began sometime in the 50s when a UCLA scientist first developed “artificial simulation bio selection osmosis membrane”. It was the first time an artificial membrane mimics the natural osmotic process and replicated in a laboratory.

In 1960, the first acetic acid fiber was used as R/O membrane and it was a breakthrough. To date, the U.S. government spent $4 billion in the development of the technique.

At that time, it replaced the only (and very expensive) method of fresh water production from sea water which was distillation.

NASA funded the costs of development to solve the drinking water consumption problems in space. Today, the R/O process is used to purify and recycle used water. In aircraft carriers and submarines, all the fresh water supply is taken from purified sea water.

Today, a home water system using the R/O process can provide 285 liters of drinking water, enough to fulfill the needs of a small office or a regular household.

Nowadays, the water purification systems for home use have three pre-filters. This first stage filters are designed to remove sediments and other solids from the water. The first stage activated carbon filter is used to remove organics, chlorine, and odors.

The osmotic membrane then removes most of the dissolved impurities (metals, chemicals, etc.) in the water. Finally, the last activated carbon filter is used to remove the remaining residue contaminants after the R/O membrane.

Care should be taken to replace old filters and other worn parts. This will ensure that the continued use of your reverse osmosis water filtration system is always in top condition.

The Pros And Cons Of Reverse Osmosis

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Reverse osmosis (also called R/O) is one of today’s very timely technological breakthroughs: producing fresh, clear water from contaminated water or those with impurities that cannot be taken out by even the finest filters. Of course, as in all things, there are pros and cons of the idea of reverse osmosis.

Basically, the process is simply forcing contaminated water through a semi-porous membrane and filtering out organic compounds such as salts and other minerals, chemicals, dyes, sugar, many other TDS (total dissolved solids) thereby producing fresh and clean water ready for use again.

Using the reverse process of the natural osmosis, R/O technology is now used in homes and offices, as well as by big industries. So far, this process is now the world’s leading technology in the treatment of contaminated water and makes it clean and safe for human use again.

Advantages

Because it eliminates 95 to 99% of TDS (total dissolved solids), reverse osmosis is the best technology today for getting clean water free of contaminants.

R/O systems remove salt, dissolved minerals, nitrates, pesticides, metals, and microorganisms from the water. The system is also effective in treating water for health contaminants like asbestos, arsenic, some pesticides, fluoride, lead, mercury and radium. Removing them gives back the sparkling appearance and taste of water.

Today, R/O systems provide such diverse uses as drinking water, rinse water, car wash water reclamation, pharmaceutical production, ice-making, laboratory and other biomedical applications, farming, and providing clean water to so many other industries that use it.

In fact, one pundit says R/O provides water for the kitchen counter in a private home as well as water for use in space.

What makes it also ideal is the fact that installation costs are low, has very minimal use of chemicals, and with the construction using low-maintenance, non-metallic materials. The technology is also used right now in removing organic and inorganic contaminants from water.

Disadvantages

The R/O process, however, have some several downsides.

Despite their effectiveness, the R/O membranes are susceptible to loss of function. Due to the size, shape, and the amount of contaminants present, a buildup of materials might disable the membrane’s functions. Also, the widely-used disinfectant chlorine can attack the membrane.

The small pores of the membrane block particles of large molecules but some pesticides and chlorine are molecularly smaller than water and can pass through. This is why carbon filters must be used as supplement to the R/O process because it can remove chlorine in the water.

Another drawback to the R/O process in purifying water is the fact that it blocks and removes healthy, naturally-occurring minerals in the water. These trace minerals helps provide the natural taste of water and they may be of vital use to the body.

The process wastes a large portion of water, around two to three gallons, for every gallon of purified water it produces. Moreover, the technology needs a reliable energy source and a good spare parts inventory (if it is foreign-made).

The process is slow compared to other water treatment alternatives, requiring a holding tank so that supply is assured during peak use.

The membranes used in R/O are sensitive to abuse. The feedwater usually needs pre-treatment to remove solid particulates. Presence of particulates cuts short the life span of the membranes.

However one may look at the pros and cons of reverse osmosis, one may conclude that until a better, foolproof technology of water treatment comes around, reverse osmosis is still the best technique there is today.

The Many Applications Of Reverse Osmosis

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The discovery and development of reverse osmosis is one of today’s most useful technological breakthroughs. Since the early 50s, it had served its primary purpose of providing safe purified water where it had not been available before. The following are the many other applications of reverse osmosis.

Drinking water

All over the world, the technology of reverse osmosis in providing safe drinking water in households is now common both for homes and big establishments.

In the U.S. military where it was first developed, R.O.W.P.U.s (Reverse Osmosis Purification Units) produce 12,000 to 60,000 gallons of water for 1,000 to 6,000 soldiers.
The purified water is also safe from NBC (nuclear/biological/chemical agents) after the reverse osmosis process.

wastewater

In big cities and progressive areas, collected rainwater is purified with reverse osmosis and used for irrigation of landscapes and industrial cooling.

For big power plants, reverse osmosis is used to remove the minerals from water used in the boilers. The water has to be pure and free from minerals that leave deposits on the machinery and cause corrosion and other damages.

In Singapore, the authorities had announced their intention to use reverse osmosis to treat their wastewater before discharging them back into the reservoirs.

Food industry

Reverse osmosis is used in the concentration (thickening) of food liquids (orange juice, tomato juice) that lose their nutritional values if processed with heat.

It is also used in the dairy industry in the production of whey protein powder and the concentration of milk to reduce shipping and storage costs.

It is already used by the wine industry, although it had been frowned before. Now, reverse osmosis machines are used by many wineries in France, even by well-known companies. The machines were used to concentrate the grape juices, and removing taints as acetic acid, smoke, and the removal of alcohol in some.

In the 70s, maple syrup producers began using reverse osmosis process. They were used to remove excess water from the raw maple sap before boiling. The practice removes around 80% of water, saving them in energy consumption because it reduced boiling time of the syrup.

Car wash

In places where there is ‘hard water’, enterprising car wash entrepreneurs employ the use of reverse osmosis machines.

Hard water causes water spotting on vehicles. Reverse osmosis removes the heavy minerals in their original water. Reverse osmosis also reduces demands from customers for drying their vehicles which adds costs.

Reef aquariums

Many reef aquarium keepers are now using reverse osmosis systems to produce water for their artificial mix of seawater. They found that ordinary tap water often contains excessive amounts of chlorine, chloramines, heavy metals, and many other chemicals that are bad for the reef environment in their aquariums. Other contaminants such as nitrogen compounds and phosphates lead to excessive algae growth.

Today, reef aquarium owners use the combination of reverse osmosis machines and deionization because of low ownership costs and minimal running costs.

Desalination

In places where there is limited water, authorities use reverse osmosis technology to desalinate the sea for their drinking water. In the Middle East especially in Saudi Arabia, large reverse osmosis and multistage flash desalination plants are in harness. The energy requirements are large, but they are offset by the fact that these countries are oil-producers.

So far, these are just some of the many applications of reverse osmosis, although there had been other small uses as well using the principle of the process (in hydrogen production, organics removal, etc). It will not be a surprise if more uses will be added to this list.

Singapore Leads Efforts to Further Improve Reverse Osmosis Technology

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It is estimated that in at least 15 years, about half of the global population would have reduced or no access at all to drinking water. Singapore is one of the countries that are expected to be hit severely by further depletion of potable drinking water supplies. That is why the national government is actively working to boost production of drinking water supply in a more energy efficient and affordable way. It is eyeing more effective and cheaper approaches to reverse osmosis.

Within the state-country’s busy center is a building that houses a test laboratory, which is being groomed to emerge as a major and significant player in the local water business. ‘Water Hub’ is a two-year old facility that has been testing and using most advanced available technologies and techniques for water reuse and reclamation. It has been establishing itself as a significant frontrunner in bolstering international research initiatives for water purification through reverse osmosis.

For the past decades, the Singaporean government has been aggressively finding sustainable and more effective means of water treatment to be able to provide safe and potable water supply to its major industries and about 4.8 million people in its territory. The realization of depleting water resource has prompted Singapore to initiate competition and efforts to be able to find and secure the most energy-efficient and cost-effective way of converting ordinary seawater into safe and useful drinking water.

Water Hub is funded and supported by numerous local firms and organizations. Among those companies is Siemens Water Technologies. The firm has won the ‘Singapore Innovative Technology Challenge’ in 2008 for its new seawater desalination technique. The company’s process is able to lower energy consumed for reverse osmosis by up to 90%. The technology is facilitated through channeling seawater for treatment through a reliable electric field rather than the conventional energy-intensive vaporizing and heating processes.

In traditional reverse osmosis, salt in water is effectively filtered out via porous membranes that could retain about 99.7% of salt in seawater. This way, safer and more potable drinking water is produced without any need or requirement for post-treatment. Through the years, many companies and governments that use the process have been complaining about the usually high costs and tediousness of performing reverse osmosis. In fact, world organization Water Aid has excluded the process in its list or recommended water purification techniques because reverse osmosis is usually too expensive, especially when conducted in a massive scale.

Singapore is one of the countries that are acting aggressively to any water supply problem in the future long before such setbacks occur. The national government hopes its intensive research efforts could help it lead a global effort is eliminating possible safe and potable water supply depletion in the future. It also recognizes the fact that there is a need to find cheaper and more efficient methods for reverse osmosis so that developing countries could also reap the benefits of such technology.

Researchers at Water Hub are also actively aiming to patent a green technology that could pave the way for alternative sources of energy. The group believes that aside from making reverse osmosis more viable and useful, other related measures should be discovered and developed to help make the world a better and safer place to live in.

Review of Osmosis to Explain Reverse Osmosis

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Have you heard about reverse osmosis? It should truly be a useful and advantageous process of liquid purification because more and more industries are using it. Around the world, the importance of reverse osmosis is also becoming more emphasized. As many experts say, the process holds a lot of potential. It could be a system that could eventually bring about aid and redemption. But what exactly is it? Why is it truly effective? Could it be done using improvised setups? How does it work?

It would just be impossible to understand reverse osmosis without first understanding normal osmosis, where it is derived from. As you could infer, reverse osmosis is only an opposite take of the usual process of osmosis. The dictionary defines osmosis as a natural movement of solvent molecules through semi-permeable membranes so that they could transfer into the side where there is there is lower concentration of solution. In the process, concentration on different sides is equalized so that in the end, there would be no difference on concentration. Osmosis naturally stops the moment such equality of concentration is achieved.

Semi-permeable membranes are membranes that are serving as boundaries between two regions. They are structures where molecules could pass through. Example is a saran wrap, which looks impermeable but is actually permeable. Other good examples are cell walls and intestines. There are very small pores that could allow entry of very miniscule molecules of water. Such pores are too small that they do not allow passage of other liquid molecules and other bodies. Gore-tex fabric could also be an example.

In reality, osmosis is the very same reason why consuming or drinking salty water is very dangerous. Drinking seawater or ocean water could kill anyone, especially if there is much volume consumed. When you do so, the salty water would be temporarily stored into the stomach. Natural osmotic pressure would work and begin drawing water from other parts of the body so that your body would be able to dilute the amount of salt molecules that are stored in the stomach. When the process goes on continuously, you would eventually dehydrate, which could lead to death. It could take only a few minutes or hours for the body to complete the process. This is one of the reasons why many people who drown in sea die.

Reverse osmosis is the exact opposite of the natural osmosis process. The idea is for the semi-permeable membrane to serve as a fine filter that would create safe and potable drinking water out of the contaminated water. This process could very much be illustrated through desalination. Salty water is stored in one side of a membrane, while the less salty is on the other. Pressure would be applied to stop and later reverse the natural osmotic process. Usually, this setup would require much pressure and would take a long time to complete. But there is no doubt that it would truly and effectively work.

Reverse osmosis is now widely used as a process of purifying water. It is also the same concept used in dialysis. Many industries are also starting to use reverse osmosis in their operations. Even disinfection activities could now use this helpful and useful process.

There is no doubt that in the future, many devices that facilitate the process would be more widely available for any household to use.

Reverse Osmosis Water System for our Protection

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The title itself is a mouthful. Nonetheless, there are very important benefits of reverse osmosis water systems to our own health which makes the process very important to our daily lives. In its most simple description reverse osmosis is a filtration process which is often used for purifying water. The process uses membranes with micro-pores which allow the molecules of water to pass through but filter out anything larger.

This way, the pollutants or particles present in the water are not allowed to pass through which results to clean drinking water. The whole filtering process takes longer than other kinds since passing all that water through a super fine membrane takes some time.

There are a lot of households that use this kind of purification system. Typically the purifier includes layers of sediment filters which initially remove particles like rust from the water. The filters usually have different pore sizes and are intended for various kinds of particles. One of the filters is a carbon filter which can trap organic chemicals and chlorine.

And then finally there’s the reverse osmosis filter which is a thin film composite membrane. The combinations of layers of different filters make the purification process more effective. Using for instance carbon filters and reverse osmosis filters ensure that a lot of impurities in the water are removed.

One good thing about reverse osmosis systems is that it does not require any electricity for it to work. Unless you’re using ground water and pumps for your water supply, the normal pressure from taps are enough to push the water through the layers of filters or membranes. Of course, the membranes and filters need to be replaced regularly since sediments and particulates can accumulate rather quickly.

Not only do impurities are removed from the process, but whatever odors the water has are removed as well. Also, unlike other filtration systems, reverse osmosis does not use any chemicals or its filters which lessens any possibility of chemical contaminations. And in the long run, the filtered water can be used for cleaning tiles, sinks, faucets and toilets since the water does not contain any dissolved minerals and metals which can turn out to be harmful even for household equipment like water heaters.

Now despite the advantages, using reverse osmosis filtering systems do have a couple of disadvantages. First is it will need a lot of pressure from the water to push itself through the membrane. Ideally the pressure from the tap should be at 40 psi or greater. If you live in an area where water supply is not reliable having a reverse water osmosis system might prove to be quite the liability.

Another issue is that the membranes used are not able to filter out ultra fine water pollutants like insecticide and pesticide molecules. These kinds of contaminants can still find their way into your drinking water. However, unfortunately because of the fine membranes the process also removes the important minerals present in water which our body needs as well. So it odes not necessarily mean that since the water that comes out of the reverse osmosis process is pure, it is healthy for our use.

Finally, using reverse osmosis for our protection will produce too much waste water because of the process itself. Because of the pressure and the super fine filters, much of the water that passes through the system will not pass through. Gallons of water are wasted for every gallon purified. However, waste water can be channeled back to the ground water.

Reverse Osmosis in Industries

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After hearing about reverse osmosis, the first thing that probably pops to your mind is a water filtering system that is commonly used in our homes. Although that is a fact, the truth is reverse osmosis is process which has a number of uses aside from providing safe drinking water. In fact reverse osmosis has played an important role in medicine and in various laboratories. And, of course, you cannot discount the fact that reverse osmosis in industries has been utilized extensively. The application to industries is one of the largest uses of reverse osmosis. The production of clean water is as vital to the manufacturing level as it is in the domestic home front.

One of the more large scales common uses of reverse osmosis is boiler feed water treatments. Through the process, the water is pretreated which allows water that has considerable amounts of solids or contaminants removed before they are passed through the boilers. The objective here is get purified steam and to prevent contaminants to clog various stages of the system. The use of reverse osmosis in boiler feeds is more common in power plants and petrochemical plants. Any impurities in the steam that turns the turbines can cause downtime in generating electricity. Power producers can loose a lot of money from low energy production efficiency and they can loose more money when their turbines get damaged.

Reverse osmosis has revolutionized the way these industries purify their water. Traditionally, power plants used hazardous chemicals like sulfuric acid and caustic soda to purify the water they used to generate steam. Shifting to reverse osmosis carry a number of benefits including totally avoiding those harmful chemicals and also the costs benefits since in the long run running a reverse osmosis system is becoming cheaper than purchasing those chemicals.

The beverage and bottled water industry is perhaps the second largest user of reverse osmosis systems. You can see just how many companies use it by looking at the various brands of purified, drinking flavored drinking water in your local supermarket. These companies use the reverse osmosis system combined with other filtering technologies to ensure quality and clean products. Beverage companies cannot afford to mess up in this aspect since any bad publicity due to the quality of their products will loose the credibility of their company resulting to millions of dollars in losses.

Pharmaceutical and semiconductor industries also require the use of pure, clean water for a varied of reasons. In semiconductor production lines for example, the use of ultra pure water as a final step of some cleaning processes is absolutely necessary. Any impurities can cause problems with the sensitive nature of a variety of the products such as semiconductor wafers and other electronic components. The same can be said with pharmaceutical applications. The importance of pure water in creating medicines simply cannot be undermined. Aside from the production side, industries often utilize clean water produced from reverse osmosis to clean, disinfect and maintain equipment and facilities.

And with the evolving nature of industries, it would not be surprising to see new and innovative ways reverse osmosis in industries is utilized. In fact, reverse osmosis has already found its way in small scale products and manufacturing including humidification, waste water treatment, reclaiming car wash water and other rinse waters, photography, kidney dialysis, animal feed, cosmetics, hatcheries, greenhouses, metal plating production and battery water use.

Reverse Osmosis Could Filter Out Unlikely Chemicals in Drinking Water

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Reverse osmosis has been around for quite some time. It is so far the most effective and viable technique of purifying water supply to make it safer from drinking and general consumption. While it is a common knowledge that the planet is two-thirds water, it is also a fact that many nations around the globe and suffering from lack or significant depletion of available natural drinking water. Other than that, reverse osmosis is also identified as the best method to make sure water supplied to households are safe and are free from any unwanted chemicals and impurities.

The process of reverse osmosis is also becoming more popular and useful in the United States, not because there is a great depletion of drinking water but now more because the technique could help assure overall quality and safety. Many states are now adopting the use of reverse osmosis technology to make sure drinking water supplied to every American home would not bring about adverse and unlikely health hazards.

There is a spreading rumor that there is a high volume of contraceptive chemicals that are found in drinking water in several cities and states in the US. Tests have proven that this is more than just a speculation. It has been determined that there is actually trace amounts of artificial birth control substances and other medications in water supplied to households and industries. However, there is still a considerable debate whether this would be taken as a general health risk.

The US Geological Survey in 2008 tested water in about nine states across the US. It found that there are about 85 man-made and artificial chemicals in water from the faucet. A separate report from the Associated Press said minimal amounts of numerous medication substances combine with tap water that is supplied to some 46 million US citizens. However, it has also been found that the chemicals and substances are very much diluted that they are not posing any potential to induce any slight health effect.

Among the dangerous contaminants found in tap water is estrogen, which is inadvertently accumulated and released into sewerage from urine of women who are taking contraceptives or birth control substances. This form of estrogen could wreak havoc on reproduction of fish. It could also cause growth of breast cancer cells in men and women. There are many other contaminants found in tap water flowing from household faucets. Health experts warn that exposure to such impurities could pose still unknown health dangers and risks.

Initially, experts assert that basic burden of protection frequently lies to the hands of users. Thus, there are now many kinds of small-scale or in-home filtration systems available. It is surprising how sales of such products are rising, even if there are no regulatory approvals or proofs that they work. It shows that many American households are getting more concerned now.

The best way to filter out such impurities is of course reverse osmosis. There are now portable devices available for small-scale water filtration intended for household use. Many water distributors are also investing in facilities that would carry out reverse osmosis techniques to make sure water supplied to consumers are completely free from hazardous and dangerous chemicals and impurities, even in trace amounts.

Reverse Osmosis as a Water Treatment Process

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The use of reverse osmosis as a water treatment process or technology started more than four decades ago. It emerged as an effective alternative technique for desalinating abundant seawater. You see, the world’s surface is up to two-thirds covered by ocean and seas. But why is it that many countries and cities are still lacking adequate supply of potable water? That was the concern when scientists and researchers started exploring many more ways of converting water from ocean and sea into a form that would be most useful to households, industries, and people.

Upon the wide recognition of the water treatment method’s decontaminating and purifying capabilities, systems for reverse osmosis started getting commercial production and distribution mostly for household water purification purposes. These systems have been installed in many homes since the start of 1970s. Reverse osmosis devices and facilities have instantly become a more viable option to the costlier and more energy-wasteful units of water distillation.

The process is depending mostly on the semi-permeable membranes through which pressurized liquid or water is forced into. The use of force is a necessary factor because logically, reverse osmosis is simply the exact opposite of natural osmosis. As a review for your general science lessons, osmosis is the tendency of water, the universal solvent, to migrate or transfer from a solution with weaker saline content into a solution with stronger saline concentration. This phenomenal process is considered as nature’s way of gradually equalizing or balancing saline composition of solutions, especially when there is a semi-permeable membrane that separates them.

In reverse osmosis, there should be force applied so that water would move in the reverse direction: from the solution with stronger salinity into the solution with a weaker concentration of saline. There is again the presence of a semi-permeable membrane. Why not the movement of salt molecules? In particular, salt molecules are physically bigger compared to water molecules. Because of that, the membrane would block the passage of even the tiniest salt particles or molecules. The result: desalinated water on a side of the membrane and a more concentrated solution of saline on the other.

In the same process, reverse osmosis is touted to do the same involving water contaminants. Because of this, the process has been known as an effective and highly reliable water purification method for production of safer drinking water. Many businesses are now capitalizing on the use of reverse osmosis in producing safe and quality potable water for general use of people.

There are pros and cons to the use of reverse osmosis as well. For the advantage, of course, the process is used when there is a goal to produce safer water for consumption. The method is also used when separating water from other forms of contaminants or impurities like lead, iron, manganese, salt, and calcium. Even additive fluoride in tap water could be eliminated through reverse osmosis.

For the disadvantage, many water treatment businesses know for a fact that reverse osmosis facilities are naturally more expensive than other water purification techniques. There is also a known limitation. It would not work in filtering out volatile organic chemicals and chlorine. This is because such impurities are too small their molecules are even smaller than those of water. They could also pas through the stringent pores of semi-permeable membranes.

Reverse Osmosis And Distillation Compared

2010-09-21T10:26:00.007-07:00

Today, there are two leading technologies in the water purification markets, namely, reverse osmosis and distillation. Lately, however, there is a controversy a-brewing among manufacturers of these water purifying machines and devices. The following is a comparison between reverse osmosis and distillation.

First, we shall examine each of these processes.

What is reverse osmosis?

According to its proponents, reverse osmosis (also known as hyper filtration) is the finest water filtration system at the moment.

One of the contentions is that the process removes particles as small as molecular ions from a solution. It purifies water by removing dissolved salts, minerals and other impurities and brings back its taste, color and its other properties.

Its other use is purifying other fluids such as ethanol and glycol through the reverse osmosis membrane and straining out ions and contaminants.

There are other very useful uses of reverse osmosis and its technology, but the most common is in purifying water.

Reverse osmosis uses a semi-permeable membrane that allows the fluid being purified to pass through while blocking the present contaminants. These membranes have microscopic pores that are small enough only for water molecules and not the others.

Today, most of the reverse osmosis technology also employs the method called crossflow. This is where the membranes continually clean themselves. As water passes through, the rest continues downstream and sweeps the rejected substances away.

Reverse osmosis needs a driving force to pressure the fluid through the membrane, and this is done by a common pump. The higher the concentration of rejected fluid, the pressure needed grows higher as well.

At present, the technology of the 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. Meantime, the ions are separated with the help of charged particles. Ions with charge (like salt) are rejected by the membrane and those with no charge (such as organics) are let in.

How does distillation work?

Distillation is a water purification process that uses a heat source. Water is heated and vaporized to separate it from contaminants.

The heat is kept constant to prevent the other unwanted elements from vaporizing. This is because water has a lower boiling point than salt and other mineral sediments. Distillation also separates disease-causing organisms from the water molecules.

Once all of the water has vaporized, the vapor is led into a condenser where it is cooled, and reverts back to its liquid form into a receiving container.

The remaining elements, whose boiling points are too high for vaporization, are left in the original container as sediment. Distillation is often repeated to ensure that all sediments are left behind in the process.

Many alcoholic beverages (brandy, gin, whiskey) are distilled with apparatus similar to that used in water distillation.

Because of the cost of heating in the distillation process, solar power was looked up as an efficient alternative. However, solar power only works with relatively small amounts of liquid. Multiple distillations is also out of the question because of time constraints.
More solar distillation experiments are still in progress, though.

Is a reverse osmosis unit like a distiller?

The processes are totally different. A distiller is like a tea kettle – it boils water, catches the steam, and condenses it back into water.

Reverse osmosis strains the water with a very tight semi-porous membrane. Both systems however rely on carbon filters to remove some chemicals.

Which water is purer – those produced by distillers or by reverse osmosis?

Distillers remove sodium and other common minerals better than reverse osmosis. But they are not that good in removing volatile chemicals with low boiling point.

Reverse osmosis with the carbon filters remove chloramines (the current favorite water disinfectant) best.

Both, however, produce very pure water. Actually, with reverse osmosis and distillation compared, the only difference would be the economics of ownership costs and maintenance expenses.

Reverse Osmosis And Desalination

2010-09-21T10:26:00.005-07:00

Today, man’s needs for resources are growing in leaps and bounds and technology is hard put just to keep in stride. One of these is the dire need for water. As a matter of fact, in certain places in the world the need has been getting more and more urgent daily. Technology’s answer at the moment is water desalination through reverse osmosis.

Reverse osmosis

Reverse osmosis is the process where contaminated water is forcibly passed through a membrane straining the impurities in the water and collecting the clean water. Desalination is a reverse osmosis process where the salt content of saline water is reduced to a usable level.

In regular reverse osmosis process, impurities are easily removed from the water. Some substances dissolved in water like calcium carbonate are removed easily, but some like sodium chloride (salt) require more complex methods like desalination.

Before, it was difficult and economically impossible to remove dissolved salt from saline water (from sources like sea water or salty ground water sources). In the 50s, however, the economics of desalination finally became viable under certain circumstances.

Desalination

Desalination, the process that reduces the dissolved salt content of saline water to a usable level, entails three liquid streams – the saline feed water (brackish or seawater), the low-salinity product water (the usable water) and the highly saline concentrate (brine or reject water).

The product water generally contains less than 500 mg/I dissolved solids. This concentration is already suitable for most domestic, industrial and even agricultural uses.
In the end, this had solved the age-old problem of coastal communities surrounded by all that saline water but having no way to use them.

Reverse osmosis membranes come in two popular types: the spiral wound, and the hollow fine fiber. Generally, they are made of cellulose acetate, aromatic polyamides and polymer film composites.

They are all used for brackish water and seawater desalination, albeit the specific membrane and pressure pumps vary according to the pressures fit for each.

For desalination using brackish water, the operating pressures range from 250 to 400 psi. (pounds per square inch). Seawater desalination uses 800 to 1,000 psi.

Because no membrane is perfect in its rejection of dissolved salts, a small percentage of salt passes through the membrane and remains in the product water. This product water is usually adjusted for pH and degasified before being used for drinking.

Degasification is having the water aerated and the pH (acidity) level is adjusted accordingly. Usually, the water is first stored in containers before being used.

Other uses

Desalinated water through reverse osmosis has been used as potable water for industrial and agricultural purposes. Newly-developed membranes are now designed to withstand higher pressures. They are also more efficient now in removing around 60% to 75% of the salt, plus almost all organics, bacteria and other chemicals in the water.

This is also used during the manufacture of electronic parts that need water, specialty food, and in the pharmaceuticals industry.

In agriculture, greenhouse and hydroponics farmers are now beginning to employ reverse osmosis to desalinate and purify their irrigation water in their farms. One happy bonus they discovered is that their desalinated water has lower counts of bacteria and nematodes. In turn, this greatly helped in controlling plant diseases in their farms.

In South America (like some parts in Argentina, Brazil and Chile), reverse osmosis desalination is now being used on a starter scale. It will only be a matter of time when more and more places in the world will adopt this new technology.

Reverse Osmosis – Some User Tips

2010-09-21T10:26:00.003-07:00

Today, most households have opted to have their own water purifying systems. This is largely due to the inadequacy of local utilities to provide safe, potable water for general home use. One of the more popular water purifying systems today is the reverse osmosis process. The following are some user tips for reverse osmosis subscribers.

Water tests

Before deciding any water treatment system for home use, get a thorough chemical analysis of the available water in your area. You can get a copy of test results that are regularly required from your municipality or the handling water company.

If it is from a private well, have the water tested and certified. No single water treatment system is designed for all water problems. In case the water supply has high dissolved minerals, a reverse osmosis system is a good choice.

Reverse osmosis (R/O) system installation

The total R/O system usually takes around one-half of the space underneath the sink.
The biggest component is the pressure tank that holds the treated water. This tank should be in upright position to prevent leakage, and placed in a heated area to prevent freezing in winter.

The reverse osmosis unit itself should also be kept from freezing, and must be placed accordingly that there is elbow room for changing filter cartridges. Note that the R/O system is designed only for cold water.

R/O systems can produce around a gallon of water every two to four hours. It is not advisable for activities like washing or showering. R/O systems for the entire household would be extremely expensive.

Foul-smelling hot water

The chemical that causes it is in the incoming water, most noticeable in hot water because the chemical becomes gas at higher temperatures. The “rotten egg” smell is caused by hydrogen sulfide present in the feed water (source) and carried to your house.

Odors like petroleum or rotten eggs can be removed by using activated carbon filters, available in cartridge filtration systems or stand-alone units.

Water pressure

The water pressure that drives the water through the membrane in the R/O system needs to be monitored from time to time. There is a limit how much pressure the membrane can tolerate before cracking. It varies between units and specified in instruction guides.

Comparing costs

It is always a good policy to compare prices before buying anything – including water purifying systems. Compare the overall costs (installation and the regular maintenance costs) of the reverse osmosis system with the estimated total costs of buying your entire drinking water in bottles.

Sometimes, the convenience of having reverse osmosis system in your home can cost you more than buying regular bottled water. Be sure to compare prices and the respective brands.

The site of the National Sanitation Foundation (www.nsf.com) can provide much useful information to help you compare and decide.

Other problems

The reverse osmosis system cannot solve all your water problems. First, sand and silt quickly destroys the membrane. It is not ideal for removing bacteria, petroleum or slime. Slime materials coat the membrane making it ineffective.

This means the R/O system is not effective for water that is contaminated with natural gas and chloroform. A high level of chlorine is also bad for the system.

These are some of the reverse osmosis user tips that can help you install your R/O system at home. Or, it could alert you on some things if you have not chosen yet any water purifying system for your home.

Pros and Cons of Reverse Osmosis

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Through the years, reverse osmosis has been widely used worldwide for treatment of water. Not all forms of water present in the surroundings could be potable and used for natural and household purposes. Through this process, water is purified by filtering out contaminants. Through the use of a semi-permeable membrane, reverse osmosis works upon application of external force or pressure. It should reverse the natural process of osmosis and force out pure water from a solution containing many contaminants or solutes. Of course, the advantage is quite logical: safer and more purified water is produced.

There are several disadvantages of reverse osmosis. One of the many known downsides is its potential to become an ineffective and inefficient means of water purification. The semi-permeable membranes used for facilitating osmosis and reverse osmosis contain very small pores that are able to block small particles or molecules except pure water. This is the key to the usefulness of reverse osmosis. However, there are several known contaminants that are molecularly much smaller than water. They include dangerous chemicals like herbicides, chlorine, and pesticides.

There is a better method used instead of reverse osmosis for filtering out molecules that are smaller than water molecules. Carbon filtering is it. That is the reason why many water treatment facilities employ both reverse osmosis and carbon filtering techniques. This way, water could be made more purified and safe for drinking and other forms of consumption.

Another setback for the use of reverse osmosis is the unintentional but inevitable removal of healthy and naturally occurring minerals that are found in water. If the process could filter out contaminants and impurities, unfortunately, it could also do the same for important trace minerals found in water. This is because the semi-permeable membranes used are almost always impermeable to naturally occurring trace minerals in water.

Such minerals are identified as responsible for providing water better taste. They also facilitate a good function to the human system. Needless to say, if drinking water is deprived of such minerals, it could be totally unhealthy and less likely for drinking.

It is also a widely known fact that reverse osmosis puts more water to waste. In general, it would take about three gallons of water to be wasted for producing a single gallon of purified water. Water is wasted when the other membrane content is made non-useful and contaminated. There is no way but to throw away such water or take more time and effort to subject it to further reverse osmosis or other filtration process. Most water filterers opt to just throw it anyway. It is also certain that reverse osmosis is a very slow process. It could not be used in urgency as compared to other alterative water treatment processes.

What about costs? Of course reverse osmosis is more difficult to setup and facilitate. The facility is quite complicated and sophisticated. All around the world, many researchers and inventors have always been trying harder to be able to invent or devise ways to lower costs of using reverse osmosis. To this day, many companies are just drum-rolling; no definite or certain cheaper way or device of the process is actually launched, introduced, or sold in the market.

The world knows the potential of reverse osmosis, but more and more people hope it would not take long before its potential and usefulness is maximized.

Pluses and Minuses of Reverse Osmosis

2010-09-21T10:25:00.007-07:00

For the past four decades or so the reverse osmosis process has been refined into a very useful method of filtering water. From the discovery of the phenomenon of osmosis by Abbe Noilett in 1748 to the opening of the first commercial reverse osmosis plant in 1965, the process has become an integral part of commercial, industrial and our domestic lives. Its impact to the present day cannot be undermined.

However, reverse osmosis is not without any defects. The whole water filtering process is never perfect especially when we ourselves produce all sorts of new pollutants or water contaminants as by products of human race’s continuing thirst for technological advancements. Today, we have new techniques of filtering water which makes it more appropriate to review the plusses and minuses of reverse osmosis.

When reverse became commercially available forty years ago, it was a great alternative from the more expensive distillation process. The world easily embraced this new way of making our water clean and safe to drink and for other usage. The filtered water from the process became important in commercial establishments such as restaurants and hotels. Various industries also adopted the procedure especially power generating plants, pharmaceutical companies and even semi conductors and electronic manufacturers. Reverse osmosis has found its way to various small industries as well like bottled/flavored drink manufacturers, the wine industry, maple syrup production, water purifying businesses and even in reef aquariums.

Aside from costs of setting up a reverse osmosis system relative to distillation processes, another advantage of using the method is that it has been proven to be very effective in removing organic chemicals or dissolved minerals found in the water. So the process easily filters nitrates, fluoride, sodium, Giardia, sulfides, Crypto sporidium as well as heavy metals like mercury, radium, uranium, lead and arsenic. Harmful chlorine and bacteria are also removed from the water that passes through the reverse osmosis membranes. And also, since it uses no electricity and only requires sufficient amount of water pressure, the whole process is very energy efficient.

However, despite the many advantages reverse osmosis has received a lot of criticisms. For one, even though it does not consume that much energy as distilling machines, reverse osmosis does waste a lot of water and not to mention works pretty slow. On the average, to produce one gallon of clean and filtered water reverse osmosis wastes about two to three gallons of water. Also, it takes roughly an hour to fill a gallon with clean water.

Then there’s the health issue. Because reverse osmosis membranes filters anything that are bigger than water molecules, the beneficial natural minerals from water are being removed as well. According to studies, the water without these natural minerals can be unhealthy for the body. When reverse osmosis removes the alkaline mineral contents of water it becomes acidic. When we drink this acidic water, the natural reaction of our body is balance the acidity levels by taking the calcium and other essential minerals found in our bones and teeth.

More importantly, contaminants that have smaller molecules than water such as the various by products of herbicides, pesticides, fertilizers and industrial solvents are able to pass through. These chemicals can cause cancer and other degenerative diseases.

Reviewing the pluses and minuses of reverse osmosis is necessary so we can assess the relevance of the procedure today especially in producing drinking water. There are now new and more efficient ways of filtering water and turning to them could be a wiser move.

New Method Developed to Make Reverse Osmosis Cheaper

2010-09-21T10:25:00.005-07:00

A research team from the University of California in Los Angeles has announced preliminary feasibility testing for a new mobile pilot system that would make reverse osmosis significantly cheaper. The system, called M3, would be able to determine whether fresh water could be extracted effectively from any water source. This could help make the process of desalination much easier and practically cheaper especially within developing nations.

Desalination is a widely used process of purifying seawater or even brackish water to produce potable water that is safer for drinking and consumption of people. The process is massively used in about a hundred countries globally, with nations in the Middle East and other desert areas as the heaviest users. It is also becoming popular in other nations where growing population has depleted available potable water sources, like in Australia, China, Spain, and several states in the US. Desalination is effective, but it is at the same time very costly.

Reverse osmosis is a water filtration technique that is done through applying force so that water could pass though semi-permeable membranes. This way, impurities are filtered out and water is purified. The process is not a fast one, but it could be among the best ways to assure safety and effectiveness of produced potable water. The M3 system is specifically designed and used to significantly lower costs of desalination and reverse osmosis.

In the usual process, a static pilot facility should be constructed within or close to any water source. The plant carries activities to test quality of water and then assess strategies for pretreatment of water. Pretreatment is necessary in removing impurities before such substances pollute and corrupt reverse osmosis membranes. In general, this conventional practice is costly. Cleaning and replacing the membranes means the desalination plant should be entirely shut down, which is counter-productive.

Its developers claim that the portable and flexible nature of M3 means that any nation or government that is into desalination could invest in a system to use it in initially testing every potential water source. This could significantly help save time and money. Researchers are positive that the mobile system would truly be useful especially to many system providers that require similar tests at multiple sites to make sure contamination of reverse osmosis membranes would be effectively prevented.

Such mobile pilot facilities, which could even fit into any standard cargo van, could be helpful in developing nations that are considering using reverse osmosis for water quality testing and production. A standard M3 unit could produce up to 5,000 gallons of purified water out of seawater in a day. It could produce up to 8,000 gallons of safe drinking water out of brackish water. Thus, the mobile water purifying system could be deemed effective and useful even in emergency situations.

Several experts are also hoping M3 could be able to reverse the current stand or Water Aid against reverse osmosis. The safe water advocacy organization is not usually recommending the use of reverse osmosis technologies for water treatment because such systems are usually very costly and tedious.

To many, M3 could be good news as it has the potential to make purified water from reverse osmosis more affordable and available especially across third world or developing countries, where people could not usually afford paying for safer potable water.

More Information about Water Filtration through Reverse Osmosis

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The US Environmental Protection Agency is admitting that consumers could not help but be exposed to several toxic substances that are naturally found in ground and tap water. It even estimates that an American in every five consumes tap and supplied water that is violating safety standards set by the agency itself as part of the national Clean Water Act. Thus, demand for reverse osmosis, carbon filtration, and other water purification method has always been on the rise.

It should be noted that today, reverse osmosis is one of the most widely used water treatment process used not just in the US but also in 100 more other nations across the globe. It has created in itself a global $8 billion industry, as wealthier nations in the West and in the oil-rich regions spend more money and capital in establishing and operating reverse osmosis water purification facilities. It is expected that about 15 years from now, shortage of safe drinking and potable water would be a worldwide severe concern.

There are still many data and knowledge that you should know about reverse osmosis. Begin with the basic. First, reverse osmosis is a technology for water purification that uses normal water pressure in forcing water to pass through a semi-permeable membrane, which is specifically used to separate or filter out contaminants and impurities from water. Purified or treated water is usually emerging from the other membrane side, while impurities are left on the other. In the process, sediments of impurities eventually accumulate and buildup in the membrane. When that happens, it needs to be replaced.

The process of reverse osmosis is very effective in facilitating removal of specific impurities from water. Such contaminants could include asbestos, turbidity, lead, total dissolved solids, radium, heavy metals, and several dissolved organics. With the same concept, reverse osmosis is helpless or useless in filtering out lighter weight and smaller molecular volatile organic compounds, including chlorine, pesticide, and herbicides. Water could pass through the semi-permeable membrane because of its tiny molecules. However, if a molecule of an impurity is smaller than molecule of water, it could also do the same and pass through the membrane. When this happens, the filtration process gets ineffective.

One other downturn of reverse osmosis is the unintentional but inevitable removal of healthy and naturally occurring minerals that are found in water. If the process could filter out contaminants and impurities, unfortunately, it could also do the same for important trace minerals found in water. This is because the semi-permeable membranes used are almost always impermeable to naturally occurring trace minerals in water.

Such minerals are identified as responsible for providing water better taste. They also facilitate a good function to the human system. Needless to say, if drinking water is deprived of such minerals, it could be totally unhealthy and less likely for drinking.

Water Aid, a global water conservation organization is advising against the use of reverse osmosis. Why? This is because the process could break conservation practices. It usually takes about three to nine gallons of water before just a single purified water gallon is produced.

This would certainly be a concern in areas where water shortage is already a problem. The process is also very slow to defy urgency and very expensive to facilitate, especially for massive or large scale.

Is Reverse Osmosis Bad for Our Health?

2010-09-21T10:25:00.001-07:00

Although reverse osmosis offers clean water the health concerns that hound the filtered water still remains an issue today. Those who sell reverse osmosis products would argue otherwise and insist that they have no health related concerns regarding the water that passed through the filtration process.

But recent studies have shown that reverse osmosis can be bad for our health or at the very least is not really guaranteed as manufacturers or users of the system have claimed. The main reason behind this conclusion is that reverse osmosis is able to filter the natural minerals that water contains. These minerals apparently are quite important to our body and contribute a lot to our health.

Reverse osmosis works by forcing a solvent by applying pressure from an area of high solute concentration through a semi-permeable membrane to an area of low solute concentration. By doing so, the membrane allows the water being pushed by the pressure to pass through and prevents larger particles such as salt, for example in seawater. The reverse osmosis system actually uses several numbers of stages which incorporates combinations of various kinds of filters.

The first layer of filter usually uses a sediment type which prevents rust and calcium carbonate to pass through. An activated carbon filter is then next. With this one organic chemicals and chlorine are trapped. The water then passes through a reverse osmosis filter made up of thin composite membrane. Then after that one would find another layer carbon filter which is there to ensure that any particles that was able to push their way through is prevented from going further.

You can now see clearly where the reverse osmosis process has “overdone” the filtering. Unlike carbon filters, reverse osmosis removes any molecules larger than water from passing through. Unfortunately, the naturally occurring minerals are larger than water molecules which therefore are trapped by the reverse osmosis membrane.

And what’s more unfortunate is the fact that harmful substances like those found in fertilizer and pesticide runoffs are smaller than water molecules and so are just able to pass through the membrane quite easily. These contaminants are known to cause cancer and other degenerative diseases and should be the ones being filtered out. Some studies have found out that reverse osmosis is unable to filter more than 2,000 toxins found in tap water.

Aside from the health issue, wastage is also a problem with reverse osmosis. The process actually wastes a lot of water. For a gallon of purified water, around two or three gallons are being wasted and cannot be recycled.

Nonetheless, if drinking water produced from reverse osmosis is not as healthy as one might thing, other uses of reverse osmosis has proven to be quite effective. People undergoing kidney dialysis uses water from reverse osmosis to remove waste products in the body. The pharmaceutical industry also uses reverse osmosis in the various process of drug manufacturing.

However, despite the advantages reverse osmosis might have it is apparent that other kinds of water treatment offer better alternatives in producing clean, drinking water. Indeed, reverse osmosis can be bad for our health and it would be better to settle with newer and more advanced ways of water purification.

These newer systems leave minerals intact and instead remove all the organic and synthetic pollutants like those in pesticides, fertilizers and household cleansers.

Industrial Sector Increases Use of Reverse Osmosis

2010-09-21T10:24:00.009-07:00

Reverse osmosis was introduced during the 1950s. It was promoted as an effective and safe process of purifying water as well as removing salts and many more impurities so that taste, color, and properties of the liquid could be further improved for greater potability. It is not surprising that within a span of just several decades, reverse osmosis for water purification has picked up so well that it is widely used in more than 100 countries now as a means for producing safer and more potable drinking water for growing population. The desalination (a reverse osmosis technique) market even grew to emerge as an $8 billion global industry.

These days, it is noteworthy that reverse osmosis is increasingly being used even in industrial applications. This is logical and practical due to the technique’s cost efficiency and effectiveness. Currently, the process is widely used to treat industrial waste water, boiler feed water, and processed water. In the pharmaceutical industry, reverse osmosis is used to process grade water, which in turn is used for varied pharmaceutical applications. Food and beverage industry uses it to process beverages and food products for quality and safety purposes.

Even the semiconductor and metal finishing sectors are widely using reverse osmosis. In the semiconductor industry, the process is included as a standard component of treatment for the production of ultrapure water for different uses. In metal finishing, reverse osmosis systems are applied to metal finishing operations, which include production of several types of zinc, copper, and nickel.

The power generation industry is currently one of the heaviest users of reverse osmosis technology. Across the world, it is estimated that the power generation industry is attributing up to 30% of industrial water sales to the process. Electric power facilities that use gas, oil, coal and nuclear power produce steam that runs turbines. Impurities in steam could cause massive problems. How do the businesses purify water for steaming? You bet it right, through reverse osmosis.

Reverse osmosis could also be an industry in itself. In many countries, many businesses are established to produce and sell purified and safe potable water for drinking and cooking. Many facilities do just that. This is most common in desert nations in the Middle East and North Africa. In other parts of the world, reverse osmosis water purification businesses are also thriving due to growing population and industrialization, which further depletes natural potable water supplies.

Are there cost benefits? Perhaps, one of the reasons why many industries are now using the process is the cost advantage. Reverse osmosis units and membranes used are getting more and more affordable. This could be because supplies are faster growing than the already expanding demand. It is not surprising because many businesses are getting into manufacturing and designing reverse osmosis facilities, devices, and products. In the past, equipments for the process are very expensive. Now, they are more affordable, and the prices are further declining.

It is harder to imagine a world that is not using reverse osmosis is a water purification and industrial process. In the coming years, it is expected that the use and advantage of reverse osmosis would further expand to get more industries and sectors involved. By that time, the process would hopefully become more common so that even most households would own reverse osmosis devices. No water shortage would ever bother the world again.

How To Choose A Reverse Osmosis System

2010-09-21T10:24:00.007-07:00

Choosing a Reverse Osmosis system for your home (or office) depends on so many factors. You can make your best decisions if you have a general understanding of the basics of the process. The technical terms will fall into places as we walk you through some of the most frequently-asked-questions both from customers.

In a nutshell, reverse osmosis is the process where contaminated water is forced through a semi-permeable membrane via pressure to harvest pure clean water at the other end. The membrane strained out TDS (total dissolved solids) composed mostly of salts, metals, microorganisms, minerals, chemicals, etc.)

Water quality

Is the water supply potable?
An R/O system should be installed only if the water supply is deemed bacteriologically safe for human consumption, is disinfected or sterilized on a regular basis.

What is the daily quantity of pure water required?
It should produce at least ½ gallon of drinking water per person/per day.

Is the water supply adequately pre-treated?
The presence of contaminants such as iron, manganese, or hydrogen sulfide should be removed by pretreatment.

What is the level of TDS?
Drinking water should have a TDS of below 500. Water from wells have a TDS of 1000 to 5000, seawater has a TDS of 40,000.

Is the feed water supply chlorinated or unchlorinated?
If unchlorinated, chose a TFC membrane to withstand bacteria attack. If chlorinated, chose a CTA membrane that is not chlorine-sensitive. The membranes have to be replaced around every 2 years, depending on the quantity and quality of water.

What about water acidity?
The average pH is 6.9 to 7.5. Low pH is very corrosive to metals. A pH of 6.9 is ten times more acidic than at a Ph OF 7.0.

Booster pumps

Is a booster pump required?
A booster pump is needed if the water pressure is less than 50 psi, if the TDS in your water supply is over 1000, or if the water is very cold.

Performance factors

In the end, there are four factors that ultimately affect the performance of an R/O unit – 1) incoming water pressure, 2) temperature, 3) the TDS number and, 4) the quality of the filters and membranes used.

How much water is produced is governed by the pressure on the net membrane. If the pressure is increased, production goes up. It is also dependent on the temperature. The cooler the feed water, the lower the rate of production.

The force that binds the water molecules to dissolved ions or solids is called osmotic pressure. Now, the higher the number of the total dissolved solids (TDS) in the water, the higher is the molecular force that binds them.

These water molecules that are bound to the molecules of the dissolved solids need to be separated to pass through the pores of the membrane. To break the bond, there must be pressure applied on the water.

In the R/O process, more than one filter and membrane may be used. The pre-filters are for the sediments (sand silt, dirt and others). Then there are the carbon filters which pick up the chlorine which destroys the osmosis membrane.

Finally, the heart of the reverse osmosis system: the reverse osmosis membrane. The most common is the spiral wound. There are two choices, too – the CTA (cellulose tri-acetate) which is chlorine tolerant and the TFC/TFM (thin film composite /thin film material) which is not chlorine tolerant.

If the feed water is not chlorinated, a TFC membrane is used because of its greater resistance to bacterial attack. CTA membranes not sensitive to chlorine may be used. Most systems, however, use TFC membranes, with a carbon filter support.

These are the details to consider in the choice of R/O system for your home or office. Don’t forget to also discuss them with your supplier for more inside information on how to choose a reverse osmosis system.

Frequently Asked Questions On Reverse Osmosis

2010-09-21T10:24:00.005-07:00

Today, more and more people in highly-urbanized places are choosing reverse osmosis (known also as R/O) to purify their water. However, there are people still in the dark about water purification, filtration, and the like. The following are the answers to some frequently-asked questions on reverse osmosis.

What is reverse osmosis?

A. Reverse osmosis is a process where water is stripped of minerals and other impurities by forcing it to pass through a semi-porous membrane using pressure. It is the opposite of osmosis, the natural process where water seeps through a semi-porous membrane where liquid is of higher concentration.

What comes out of the reverse osmosis process is fresh, clean water ready for use.

Q. How does industrial reverse osmosis differ from those units used in homes?

A. None, except that the materials used are of industrial strengths for bigger institutions. The big systems usually use spiral wound membranes in high pressure containers. These provide larger surface areas.

Q. Is any pretreatment required?

Ideally, yes. Water should have very low silt (solids) content to keep the membranes from plugging up. This is done by way of pre-filters that remove these solid sediments.

Other TDS (total dissolved solids) like chlorine have to be removed by active carbon filters because it attacks the main R/O membranes. Some, like calcium and magnesium, chokes the membranes, and have to be removed at pretreatment.

Q. How much pressure is required to purify water?

The pressure needed is dependent on the concentration of the sediments and salts on the feedwater (the water to be purified), which is in turn dependent on the pressure from the source.

Q. How pure will the water be?

Purity is determined by two things. One is the reject ratio of the membrane which is pegged at 92% up to 99.5%. The other is the type of TDS (total dissolved solids) present in the feedwater.

However, through length of use, the efficiency (and life span) of the membranes shortens, and leakages occur over time.

Q. How do I clean a system?

Water treated with a cleaning agent is re-circulated on the high pressure side of the system for an hour or so. Then, the membrane is flushed to drain.

Small systems will have to shut down during cleaning, but in larger systems, the individual banks of membranes can be cleaned one by one.

Q. How much maintenance is involved with a system?

A properly set system, with a good pre-treatment in place, usually needs a one-hour cleaning routine once a month. Pre-filters can be checked weekly.

Q. How much does it cost to run a reverse osmosis system?

The cost is dependent on three areas: power, materials, and labor. Check your area on power and labor costs. (Labor is usually low since the system is more or less automated.) Materials are more or less the same everywhere.

Q. What about bugs (bacteria) growing in the water?

Water storage in R/O systems is optionally passed through an UV sterilization system to kill bacteria, usually during cleaning. It is good to have the tanks black or opaque to prevent algae growth.

Familiarizing with Reverse Osmosis, the Different Types

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When talking about reverse osmosis, one needs to understand what it is a reversed of. Osmosis is basically the movement of water from a high concentration to a low concentration through a semi-permeable membrane. In osmosis the water from a dilute solution will naturally move through a separating membrane to the concentrated side to equalize the concentrations of the both solutions.

However, when pressure is applied to the concentrated side, the natural flow is prevented and what results is the reversal of the process. The water will now flow out of the concentrated solution instead of into it. This is what we refer to as reverse osmosis. This process is more commonly used for a variety of filtering purposes. Reverse osmosis has a number of different types.

As you might already know, reverse osmosis is a pretty common and effective process used for filtering unwanted pollutants or contaminants from the water supply. This ensures that pure and clean water passes through the other side. Aside from the drinking water use, reverse osmosis has become quite a popular process for cleaning up our water but aside from home use, the whole reverse osmosis have become quite useful in laboratories, medical facilities, desalination, pre treatments and other industrial usage.

The differences of the basic types of reverse osmosis systems lies on the number and kinds of membranes or filters used. For instance, the reverse osmosis floor water type utilizes at least nine stages of filtration processes. Each stage removes specific kinds of contaminants. For instance the first stage removes organic contaminants which can cause bad tasting or smelling water. Because of the number of filters, the quality of the water filtered is unquestionable. However, due to the number of filters the process is relatively slow. On an hourly rate, this system can only clean a little above one gallon of water.

Another water filter which utilizes reverse osmosis is the counter top model which is great for home or office use. Depending on the manufacturer, the counter top features from four to nine filtering stages. More often than not, it also features hot and cold power switch. One the average, this filter can provide one and a half gallon of filtered, clean water per hour. A key advantage of a counter top model is being portable.

There are reverse osmosis filter systems that offer a continuous flow of filtered water. This kind does not use any storage facility. It is installed under the sink and features basically the same multi stage filters. Some would include carbon filters in their system which gives the advantage of having reverse osmosis membranes and carbon filtering technology. Since it has no tank, you get purified water only when you open the tap. This is good for areas where water supply is very reliable.

Talking about reverse osmosis membranes, we can still differentiate them from either cellulosic membranes, to fully aromatic polyamide or to thin film composite membranes. Cellulosic membranes are made up of thin dense porous substances which can come in sheets or hollow fibers. Aromatic polyamide membranes, on the other hand, are quite similar to cellulosics but react better to organic materials and generally last longer. The thin film composites meanwhile are made up of thin, dense, solute rejecting surface film which is placed on top of a porous substance.

The different types of reverse osmosis systems are not only based on the system itself but also on the filters or membranes used. When selecting one, it is important to know how much and what kinds of contaminants a system could filter.

Desalination through Reverse Osmosis Get More Demand Worldwide

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Countries in the Middle East are known for being oil-rich. But because they are mostly located in vast deserts, there is a logical and practical shortage of potable or drinking water for people. Desalination has been one of the most important activities in such countries. It involves the process of reverse osmosis. Currently, Saudi Arabia, Kuwait, and the United Arab Emirates are among the biggest desalination markets. In general, more than a hundred countries worldwide also operate desalination facilities, but it is in those Middle East nations where demand is much more significant.

Continuous proliferation of basic desalination facilities has effectively created an $8 billion global market. It is expected and anticipated that there would still be rapid growth of demand for desalination. This is not surprising because many nations are now experiencing shortages in drinking water supply. Not only are the desert countries in peril of water shortage. Now, Spain, China, Australia, and several states in the United States are also being bogged by the problem. In such countries, growing population has effectively outgrown basic and native water supplies.

Contemporary thermal procedures for water purification use reverse osmosis. These include MED or multiple effect distillation and MSF or multi-stage flash distillation. Both are highly reliable and are effective in producing significantly purer water from even the saltiest water sources. The only setback identified as of the moment is that such processes consume very huge amount of energy. This could not be a problem in oil-rich nations, where there is much supply of energy to spare. But how about in countries where supply of available energy is limited?

Other membrane-based technologies in saltwater desalination are getting more popular and useful across the rapidly expanding desalination market. Reverse osmosis systems using membranes are the technology of choice for purifying brackish water. SWRO or seawater reverse osmosis is now becoming the fastest growing niche in the desalination market worldwide for several practical reasons. First, most countries are tending to use seawater as a good source of water for purification. The world is two-thirds water, as you know.

Second, SWRO has been the most widely used and proven effective means of desalination. Membrane desalination has been known to be able to supply the fastest demand for safe potable water. Reverse osmosis techniques are expected to further account for a greater capacity for desalination globally. Many different technologies are being developed to be integrated with and to complement the current reverse osmosis measures. It is not surprising that most industries and governments give more priority and importance to RO facilities.

Seawater is easier to secure. There could be many convenient ways on how reverse osmosis facilities could get access to a vast and unlimited supply of seawater, whether they are in coasts or are in deserts. The supply of seawater could also not end, because as mentioned, the surface of the planet is about 70% water.

In the future, it is expected that many more advanced reverse osmosis technologies would arise. Most nations are hopeful that in the coming years, drinking water shortage would not be a problem anymore. Science should be commended for discovering and inventing many technologies for reverse osmosis.

The process could be relatively slow but it could yield the best and safest results.

Comparing Filtration With Reverse Osmosis

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Comparing filtration with reverse osmosis is like comparing two brothers with almost the same features, only with different ages perhaps. This is because the principle used by both systems is the same – filtering sediments out of the water.

Let us look first into reverse osmosis.

Reverse osmosis

Because of its present capacity of filtering some of the minutest substances on earth, the process of reverse osmosis is sometimes called hyper filtration. It allows the removal of particles as small as ions from a liquid solution.

The most common use for reverse osmosis process is in purifying water. It is used to remove salts and other impurities to restore the water’s color, taste, and its other properties.

The process is also used to purify other fluids such as ethanol and glycol by removing their contaminants and purify them for better functions.

The heart of the reverse osmosis process is the semi-permeable membrane that allows the fluid being purified to pass through while blocking the contaminants.

Another vital requirement to the system is the driving force that pushes the liquid through the membrane. The most common device used is a pump. The stronger the pressure needed, the bigger the driving force should be.

Nowadays, most reverse osmosis processes now incorporates the use of crossflow, the additional process where the membranes clean themselves during the operations.
As some of the fluid passes through the membrane the rest continues downstream, sweeping the rejected species away from the membrane.

To date, reverse osmosis is capable of straining bacteria, salts, sugars, proteins, particles, dyes, and other chemical constituents.

Filtration - How does it work?

Filtration involves water flowing through a granular bed of sand (or any other suitable filtering medium) at a low speed. The action permits the filtering media to retain most solid materials while permitting water to pass through.

To ensure adequate removal of unwanted particles, the process of filtration is usually repeated. This process is generally known as slow sand filtration. It is the oldest method of filtration but still in use up to this day.

The more modern filtration systems today use carbon as the filtering medium. The carbon is compressed into solid blocks. (This is in direct contrast to the old loose granular sand filters of old.) The carbon filters in solid blocks often include other media substances, and called multimedia filters. This new type of filter works together and in both ways, chemically and physically.

Physically, it duplicates the old work of the slow sand filters: blocking the passage of unwanted materials with molecular structures larger than that of water.

Chemically, it does additional work by the process of absorption. With it, the atomic charge of the carbon and other media encourages unwanted particles to abandon their bond with the water and attach themselves to the filter. The other media included in the filter are designed for more particles to bond with it.

Water is then directed to several stages of carbon and multimedia filters to ensure removal of more unwanted materials. The first removes the most concentrated chemicals (chlorine, etc.) and the other next stages are for the removal of smaller and more hard-to-get chemicals like pesticides.

Some notes on reverse osmosis and filtration

Carbon and multimedia filters possess the same purifying capabilities as reverse osmosis and distillation. All three – filtration, distillation, and reverse osmosis – are all able to remove dangerous chemicals.

The slow process of carbon and multimedia filters does not need expensive energy sources like distillation (heat) and reverse osmosis (force pump), thereby making it cost-effective. It wastes little water in the process, too.

Again, when comparing filtration with reverse osmosis, the issue might all boil down again to cost-effectiveness in maintenance and ownership of either of these water-purifying systems.