Dask Services: Water Filters Cyprus / Φίλτρα Νερού Κύπρος Everything you need to know about pure Water (by: Dask Services)

Solutions

Bacteria Reduction

Filters can be a good place for bacteria to grow because there is plenty of water present, filters are dark and warm, and bacteria can feed on the organics present. While most of these bacteria do not pose a health hazard, they can cause problems for drinking water and filters:

Bacteria released into filtered water can affect taste, odor and appearance.

Downstream biofilm buildup and fouling can decrease a filter’s effectiveness by reducing absorption and causing premature clogging, thus shortening the life of the filter.

As bacteria reproduce and accumulate within a filter, they create what is called biofilm. Biofilm is a slime growth that accumulates on the filter membrane. The addition of a bacteriostat creates an environment where bacteria cannot grow. A bacteriostat is a compound of naturally-occurring silver bonded to a ceramic material that is completely inert. Bacteriostats are safe and proven:

Based on naturally-occurring silver.

Confirmed effective on many types of bacteria, yeast, fungi and mold.

Harmless to humans. Less toxic than table salt.

Offer broad regulatory approvals: NSF, EPA, FDA, Europe Biocidal Products Directive 98/88/EC, and the European Food Safety Agency.

Through a controlled release of low levels of silver, the bacteriostat's silver ions attack multiple targets in the microbe to prevent it from growing to a destructive population. This tri-modal action fights cell growth in three ways:

Prevents respiration by inhibiting transport functions in the cell wall.

Inhibits cell division (reproduction).

Disrupts cell metabolism.

Pentair Everpure Micro-Pure® II media plus bacteriostat set a new standard for water quality and addresses a growing public concern:

Reduces chlorine, particulates, asbestos fibers and cysts* in water.

Safe and effective antimicrobial protection for enhanced filtration – biofilm can’t grow and won’t coat the absorptive surface which would inhibit its performance.

Enhanced filter performance – greater available surface for the filter to use during its lifetime, and promotes a longer useful life.

Certified to NSF/ANSI Standard 53 for Cyst Reduction*, Asbestos Reduction, and Turbidity Reduction.

Certified to NSF Standard 42 – Mechanical: Particulate Reduction, Class I; Taste & Odor Reduction, and Taste & Odor Reduction.

Bacteriostatic Protection

What does Bacteriostatic mean in a water filtration context? Bacteriostatic filters do not kill bacteria, per say, but do inhibit the growth of bacteria within the filter*. In other words, the term Bacteriostatic means that the quantity of bacteria passing through the filtration system will remain static, i.e. bacteria will not multiply.

How do we achieve Bacteriostatic claims in Pentair Everpure filters? We use silver, a naturally occurring element that is highly effective for this purpose. Silver is known for its antimicrobial properties, is effective in fighting a wide range of microbes, and is preferred over other antimicrobials that are chlorine-, ammonia- or alcohol-based. Silver has been proven safe and non-toxic to people, animals and plants.

Pentair employs a proprietary technology to embed microscopic particles of silver in our bacteriostatic filter media. This filter media contains silver ions which attack microbes and inhibit their growth within the filter media of the water system, and also reduces off-tastes, odors and chlorine.

Chloramines Reduction

Chloramines are very common drinking water contaminants, and everybody is familiar with the foul taste & odor they create—at least from swimming pools, if not from drinking water. Usually their presence is not intended, but about 25% of the largest public water supplies in the U.S. add the simplest one, mono-chloramine, to the water on purpose. They use chloramine instead of chlorine because it is more stable in water, allowing for disinfection over longer distances.

About Chloramines
Chloramines are a family of disinfection by-products (DBPs), formed from the reaction of disinfectant chlorine with the nitrogen atom (N) in ammonia (NH3) or organic compounds containing a reactive nitrogen atom. There are many such biological chemicals in drinking water, mostly derived from the cellular debris from killed bacteria and algae. Mono-chloramine is the simplest and most common member of the group, often produced intentionally from the reaction of pure chlorine and pure ammonia.

Chloramines in general are undesirable in drinking water because they are toxic and because they smell and taste bad. However, mono-chloramine is tolerated because it is useful as a secondary disinfectant, and it is the least toxic and smelly of the group. Still, concentrations above 4.0 mg/L are prohibited. The usefulness of monochloramine comes from its comparative weakness as an oxidizing agent: it retains about 5% of free chlorine’s chemical power, which is not strong enough to use as a primary disinfectant, but it is still able to inhibit the re-growth of any survivors of disinfection. It is also too weak to corrode copper and brass plumbing materials, and therefore it lasts much longer in the mains—two or three days instead of just a few hours for free chlorine. Finally, monochloramine is chemically too weak to produce the other common disinfection byproducts—trihalomethanes (THMs), haloacetic acids (HAAs) and haloketones (HKs),, which may pose a health hazard.

Typically water utility companies use free chlorine (or chlorine dioxide or ozone) only in the early steps of water treatment. Then, at the end, just as the finished, treated water is about to leave the plant and go out into the water mains, pure ammonia is added to convert the free chlorine residual into chloramine. Without that final adjustment, the free chlorine would continue to produce unwanted THMs, etc. for several more hours and then be completely gone, leaving the system with no continuing protection.

Standard water treatment practice is to use ½ - 1 ppm of free chlorine or 1 – 2 ppm of monochloramine. Some systems attempt to counteract monochloramine’s weakness by using more of it, but all that does is increase the frequency of taste & odor complaints. There is not much difference between the smell of the two at low concentrations, but above 1 ppm the stink of monochloramine is very objectionable—much worse than free chlorine—and removing it is even more important than removing ordinary free chlorine, especially if the water is to be used for commercial food/beverage service.

Unfortunately, chloramine is more difficult to remove than plain free chlorine: it reacts only weakly and slowly with activated carbon, just like it does with everything else. That means that the water must stay in contact with the carbon much longer than if free chlorine alone was present. Many filters do not have enough carbon for the long contact time required to achieve removal. Only products with significant capacity will give satisfactory performance.

Chlorine Taste & Odor Reduction

Chlorine is a disinfectant, most commonly used to kill microbes in the water supply. If excessive amounts are used or high concentrations reside in pipes and plumbing, chlorine can impart an undesirable taste and odor in your drinking water and other beverages. It can also contribute to foodservice equipment problems such as pitting and corrosion.

Chlorine is a very common, naturally occurring chemical element manufactured from sodium chloride. It is widely used for everything from creating household bleach to manufacturing computer chips to disinfection of swimming pools. Most water utility companies add chlorine gas to raw water to kill bacteria and other harmful microorganisms to prevent waterborne diseases. While necessary for safe water, chlorine creates many problems for foodservice operations:

Chlorine gas has a very strong, pungent smell and an unpleasant taste. It is detectable in concentrations of as low as 1 part per million (ppm).

Chlorine is an oxidizing agent, and is corrosive on metals in plumbing and foodservice equipment.

Chlorine can cause damage to gaskets in equipment, making them brittle.

Chlorine reacts with natural organic compounds in the water to form potentially harmful chemical by-products such as trihalomethanes (THMs).

Chlorine is not very effective at killing cysts, which are living organisms that can cause illness. Examples of cysts include Giardia and Cryptosporidium.

Fortunately, chlorine is not difficult to remove from water. Carbon, found in many water filters, has remarkable capacity for neutralizing chlorine. Activated carbon is a mild reducing agent and chlorine is a strong oxidizing agent, so after chlorine becomes adsorbed, it then actually reacts with the carbon. The chlorine is reduced to chloride ion (as in table salt and sea water), one atom of carbon is oxidized to carbon dioxide, and both are released to the solution (desorbed). Meanwhile, most of the spots on the activated carbon, where all this took place, become “auto-regenerated” back to their original, like new condition, ready to adsorb again. For free available chlorine (FAC), this takes only about fifteen minutes, which means that a small amount of carbon can achieve an acceptable steady-state condition if the flow rate is slow or intermittent. For “combined chlorine” (chloramines), the reaction is much slower, and more carbon or more contact time is needed to achieve equivalent reductions.

Cyst Reduction

Several types of protozoan parasites infect people through ingestion of contaminated water containing their infectious forms, called “cysts” or “oocysts” (pronounced oh-oh-sists). Cysts and oocysts are tiny packets of two to four immature forms contained in tough, leathery shells, which protect them from drying out. They form in the intestines of infected people or animals and pass out the feces. They are extremely common, being found in virtually all surface water sources used for public water supplies. Unfortunately, their shell also protects them from the action of the disinfectants used by waterworks to purify drinking water, and they are so small that many municipal filtration systems are unable to remove them reliably. Therefore, to be completely safe, contaminated water supplies must either be boiled for one minute or fine-filtered at the point of use.

The most notorious protozoan parasites are:

Entamoeba histolytica, 10-20 um cysts, cause of “amoebic dysentery”.

Giardia lamblia, 8-16 um cysts, cause of “giardiasis”.

Cryptosporidium parvum, 4-7 um oocysts, cause of “cryptosporidiosis”.

These protozoan parasites are unusually efficient at causing infections—most bacteria and viruses require hundreds or thousands of them to evade the body’s defenses, but consuming as few as one of two cysts or oocysts is likely to lead to illness. The illnesses they cause are generally just a few days of diarrhea, cramps, nausea, etc. for most healthy people, but individuals with AIDS or HIV, cancer patients on chemotherapy, organ transplant patients on immune system therapy, and many infants and the elderly are more susceptible to long-term, life threatening disease. In some communities it is estimated that as much as 25% of the population may belong to endangered groups. Therefore, the efficiency of the fine-filtration used to remove them is of paramount importance.

There are no official point-of-use filtration standards, but public health officials have approved systems and products which demonstrate 3-log or 99.9% efficiency for filtration of either live cysts/oocysts or test particles with a diameter of 1 um (micro-meter, or micron). Also, NSF International, a third party certifying agency, has produced a voluntary filtration performance standard (Standard 53: Drinking Water Treatment Units—Health Effects) which has been accepted by most public health officials. NSF Std. 53 requires demonstrating at least 99.95% reduction of live cysts/oocysts, or alternately, at least 99.95% of test particles in the 3-4 um size range. That is about half the size of Cryptosporidium oocysts, which are the smallest of these parasites.

Pentair Everpure® precoat carbon filters are efficient fine-filters capable of removing these cysts/oocysts by mechanical means*. They have been tested and Certified by NSF International to ANSI/NSF Standards 42 and 53 for more than 99.9% reduction of particles 0.5 to 1.0 um in size in the general filtration test, and for more than 99.99% reduction of 3-4 um particles in the Cyst Reduction test. Therefore, concerned individuals and businesses may use their water after filtration through these filters, even in the face of a “boil water order” or other notification of the presence of cysts/oocysts, but only if it is confirmed that the water is believed to be potable in all other respects.

Deliming

Deliming is an acid cleaning process that removes mineral scale. This process is harsh to the equipment surfaces and, over time, shortens equipment life. It is also a costly process. Operators may need to delime equipment 3-4 (or more) times per year, and it can take a service technician from 2-6 hours to complete the process each time.

However, ignoring damaging scale buildup in water using equipment such as steam ovens or ice machines is not a viable option. It reduce energy efficiency, contributes to downtime, and increases service and maintenance costs.

The right filtration solution, one with scale inhibition or reduction capabilities, can help control scale, protecting your equipment investment and reducing the need for frequent, costly delimings.

Flushing / Sanitizing

Sanitizing is the process of reducing the number of microorganisms that are on a properly cleaned surface to a safe level. A safe level is defined as a 99.999% reduction of the number of disease microorganisms that are of public health importance.

Dilute mixtures of chlorine bleach and water or chemical agents designed specifically for this type of cleaning are common and cost-effective methods for sanitizing equipment in food processing operations. When used properly, they can be a very effective methods of killing microorganisms. However, an operator needs some type device to introduce the sanitization chemicals into the equipment.

The Pentair Everpure® JT Cartridge is the preferred way to introduce its popular ScaleKleen® Scale Remover or other sanitizing agents such as bleach into water-using appliances through an existing Everpure filter head.Flushing/Sanitizing

Hardness Reduction

The seven key minerals that make up most rock formations in the United States are divided into two groups: cation and anions. Cations are positively charged minerals and include calcium, magnesium, sodium and potassium. Anions are negatively charged minerals and include carbonates, sulfates, and chlorides. Each type of rock has an equal number of cations and anions, and so does each water supply.

When we discuss “hard water” we are referring to a water supply with a concentration of the four hard minerals: calcium, magnesium, carbonate, and sulfate. These minerals are components of the hard rock formations that we call lime shale and gypsum.

Mineral deposits such as limescale create major problems for food service operations that use ice, coffee, espresso, steam and warewashing equipment. Mineral scale can clog tubing and small orifices, coat heating and cooling elements, and result in increased detergent usage. Scale also causes reduced energy transfer and efficiency loss, resulting in increased energy demands for cooling or heating, and increased operating costs. Increased operating costs include the need for deliming — an acid cleaning process that removes mineral scale. This process is harsh to the equipment surfaces and decreases equipment life.

Hard water with a high pH can be treated with a water softening system or a reverse osmosis system.

Hard minerals such as calcium and magnesium, when evaporated from water or combined with heat, can form hard, chalky deposits known as limescale. These deposits can clog pipes, reducing flow, and coat heating elements, requiring more energy to heat water. Your operation loses efficiency, and your maintenance and energy costs rise.

There are different means of treating scale, such as phosphates, reverse osmosis and softening. Each treats for scale differently, for example phosphates keep mineral suspended in solution, reverse osmosis removes mineral, and softening exchanges hard mineral for soft mineral (such as sodium). Softening provides both advantages and disadvantages. An advantage is a maintained softener can provide hardness removal for many years and models can handle high volumes of water. A disadvantage is sodium must be added to the brine tank on a regular basis.

Measuring Grains of Hardness Hardness of water is measured in grains per gallon (GPG) or sometimes in parts per million (PPM). One GPG equals 17.1 ppm (Mg/l). Generally water with GPG of 7 or more is considered hard. To determine the hardness of your water, it can be tested using simple test strips or a titration drop test.

Pentair Everpure® can provide an analysis of your water to determine the correct water treatment solution for your operation.

Water Grains / Gallon Mg / l or ppm

Soft < 1.0 0 - 17.1

Slightly Hard 1.0 - 3.5 17.1 - 60

Moderately Hard 3.5 - 7.0 60 - 120

Hard 7.0 - 10.5 120 - 180

Very Hard > 10.5 180 +

High Capacity

Foodservice operations are using more water today than ever before. A myriad of industry trends are driving that increased water demand and the resulting need for higher capacity water filtration systems including, but not limited to:

Foodservice Operators (FSO) are adding equipment and expanding beverage menus, requiring larger capacities and higher flow rates than ever before.

FSOs want one-year intervals between cartridge change-outs.

Beverage and prototype store trends indicate that future restaurant, grocery and convenience store water demands will only continue to increase.

Space is at a premium today, thus FSOs would like to run multiple pieces of water-using equipment off of a single filtration system if possible.

Pentair offers a range of Everpure Filtration System solutions that deliver capacities up to 200,000 gallons (757,082 litres) and flow rates up to 15 gpm (56.8 Lpm).

Lead Reduction

Why Is Lead a Health Concern?

Lead is a toxic material, known to be harmful to human health if ingested or inhaled. Lead in the body can damage the brain, kidneys, nervous system and red blood cells. Children, infants, pregnant women and their unborn children are especially vulnerable to lead. In children, lead has been associated with impaired mental and physical development, as well as hearing problems. The harmful effects of lead in the body can be subtle and may occur without any obvious signs of lead poisoning.

How Does Lead Get into Drinking Water?
Lead generally enters drinking water from a building’s plumbing system. Lead may be present in various parts of the plumbing system (such as lead solder, brass fixtures, and lead pipes) and is picked up by the water passing through the plumbing system. The amount of lead, if any, in a plumbing system will depend on the materials from which the system was constructed. Even new plumbing fixtures can leach lead into the drinking water. The amount of contact time between water and any lead source is the greatest contributing factor to lead in drinking water. The longer water remains standing in the plumbing system, the more lead it can absorb from any lead sources present. For this reason, the lead concentration is at its highest when water has remained unused overnight or over a weekend. Additionally, factors such as water chemistry and temperature can affect the rate at which water absorbs lead.

How Do I Know If My Tap Water Is Contaminated With Lead?
The only way to know whether your tap water contains lead is to have it tested. You cannot see, taste, or smell lead in drinking water. Therefore, you must ask your water provider whether your water has lead in it. For operations served by public water systems, data on lead in tap water may be available on the Internet from your local water authority. If your water provider does not post this information, you should call and find out.

What Can I Do To Reduce Lead In My Tap Water?
If your tap water contains lead at levels exceeding EPA’s action level of 15 ppb, you should take action to minimize exposure to the lead in the water. Installing a lead-reducing water filtration system is one alternative to help address the problem and protect your business and its customers.

Low Mineral Content

Water hardness and temporary hardness (alkalinity), the limescale-forming portion of total water hardness, have the highest share of total minerals in most commonly available potable water. The healthiest, great-tasting drinking water and beverage ingredient water requires a specific and balanced mineral composition.

For specialty coffee, it is important to maintain some specific minerals and to balance the alkalinity level in the water for proper extraction of the coffee bean and grind, and the fullest coffee flavors. An unbalanced level of alkalinity can lead to a superficial acidity, which leads to poor crema, weak and/or bitter flavor, and a less than expected coffee aroma.

Low mineral content also has other impacts:

Tea shows more distinctive taste and less cloudiness.

Fountain beverages have consistent flavor and fizz.

Ice cubes are crystal clear every time.

Too little or too much calcium or magnesium will have an adverse impact on drink quality and lead to damaging scale buildup in water-using machines.

Pentair offers a range of solutions in this area, from its Everpure® Claris™ platform with adjustable hardness control, to reverse osmosis systems that allow you to set a blend of filtered and RO water to meet your desired water recipe.

Low Water Pressure

As foodservice establishments expand their beverage offerings, the resulting increased water usage can adversely impact operational performance. This, coupled with fluctuating city water flow and pressure, can lead to inconsistent drink quality, poor beverage dispenser performance and premature exhaustion of water filter cartridges.

Water filtration systems have minimum water pressure requirements. Keep in mind that if water pressure is too low, filters will plug prematurely because particulates collect only on the surface of the carbon and will essentially “cake” itself, instead of penetrating deep into the cartridge. It’s important to always put a carbon water filtration system after the water boost to help keep:

High water pressure flowing to the filter system, which extends the life of the cartridges.

Chlorine in the bladder of the water boost to prevent growth of algae and bacteria.

Particulate Reduction

Particulate reduction is achieved using mechanical filtration, the process of removing or separating suspended solids from the water. Sediment prefilters are an example of a common, particulate-reducing mechanical filter. Most foodservice prefilters have a micron rating ranging from 5 microns up to 50 microns, and are designed to remove larger particles. These are placed before other filtration systems to extend their life.

In simple terms, a mechanical filter is a barrier with a large number of tiny holes. The mixture of water and solids is pushed through the barrier by water pressure and any solid particles larger than the holes are trapped. The size of these “holes” determines the micron rating. A micron is the measurement used to describe the physical size of solid particles in any water supply. As a point of reference, one micron equals approximately 1/25,000 of an inch, and solid particles that measure less than one micron in size are occasionally referred to a “colloidal,” or sub-micron, particles.

The majority of mechanical filter products use simple, flow-through designs with Nominal Micron Ratings. Nominal means that approximately 85% of particles the size of the micron rating will be blocked by the filter. A few product designs are available with extremely high levels of particle reduction at small micron ratings. Most of these products were developed for consumer drinking water and foodservice applications, and usually carry one of the NSF / ANSI Standard 53 certifications for the reduction of cysts, turbidity, or asbestos fibers. Three features of mechanical filters need to be considered: the micron rating, the flow rate requirements for a mechanical filter product, and the total capacity of the mechanical filter.

Prefiltration

Prefiltration involves the use of a filter designed to remove particulate matter (dirt, sediment, etc.) from water prior to further treatment. Prefiltration is important for two reasons. First, larger particulate matter has the potential to clog or prematurely exhaust the filter(s) which follow it in the system. Second, the effectiveness of further treatments (e.g. chemical or mechanical) can be significantly reduced in the presence of particulate matter.

A variety of prefilter types are available. The most important way in which these filter types differ is in their “fineness”, or the size of the smallest particle they are able to filter out. Water filter fineness is typically expressed in micron size. “Micron” refers to the filter pore diameter in micrometres (µm).

Ultimately, the fineness of the prefilter required for a particular application will vary, and will depend upon the quality of the source water involved (which will help identify the size of particles present in the water that need to be removed). Multiple levels of filtration are often required – prefiltration before fine filtration, for example – as much larger particles must be filtered out before water reaches the filter intended for finer particles. Without prefiltration, these large particles may damage the finer filter(s).

It is also important to choose the correct size of filter. The “size” of the filter refers to the maximum flow rate that it is able to accommodate. There are often multiple filter sizes available for each level of fineness. The water pressure of the system must also be taken into consideration. Each filter model will have a limit to the maximum pressure at which it can operate. Also, the filter’s minimum operating pressure should be noted to ensure this pressure will be maintained to optimize system performance.

Deciding whether to add another level of filtration is a cost/benefit decision. While any form of prefiltration requires extra cost, the operator must take into consideration the costs or losses that would be incurred without prefiltration. Prolonging the life of more expensive downstream fine filters, for example, may be well worth the investment.

Reverse Osmosis (RO)

What is it and how does it work?

Science class taught us that osmosis is a natural process by which water and nutrients are supplied to living cells. The cell membrane is a natural, semi-permeable membrane, meaning only selected materials can pass through, and others cannot. An osmotic membrane allows only water to pass through easily, while restricting the passage of all kinds of contaminants. If such a membrane separates two water solutions with different concentrations, osmosis will cause water to move from the diluted solution into the more concentrated solution, as if to dilute it.

In reverse osmosis, the opposite occurs. Pressure is applied to the solution with a higher solids concentration to cause the flow of liquid to reverse (from concentrate to permeate), unlike natural osmosis. The synthetically-produced membrane allows only the water molecules with very few other molecules to pass through into a storage tank for future use. The remaining source water, containing a higher percentage of contaminants, is left to waste. The process, known as ion exclusion, occurs when ions, or charged atoms, form a barrier at the membrane surface to reject contaminants. With an RO system, it can be said that water is removed from the minerals, unlike traditional systems in which minerals are removed from water.

Because Total Dissolved Solids (TDS) cannot be removed with mechanical filtration or standard carbon filtration, a Reverse Osmosis system is one of the most effective means of filtration. With an RO system the TDS level increases on the high pressure side of the membrane as water permeates through the membrane to the low pressure side. The high TDS water is flushed down the drain, and the water that has passed through the membrane now has very little TDS and is available for immediate use.

Semi-permeable membranes are critical for reverse osmosis to be effective. Today, the most common artificial membranes are made from cellulose acetate, cellulose triacetate or aromatic polyamide resins. These membranes are tough enough to sustain the higher water pressures needed for maximum contaminant removal efficiency. Unlike ion exchange systems that need to be regenerated often, the average RO membrane can last two or three years before replacement.

When is Reverse Osmosis Applied?
In foodservice applications, there are a few specific reasons that Reverse Osmosis may be applied. RO should be considered if the TDS content in the water is high enough to:

Impart objectionable taste.

Cause scale buildup in equipment.
Cause poor quality of beverages and ice, such as weak carbonation or soft ice.

The U.S. Environmental Protection Agency (U.S. EPA) sets a secondary standard of 500 mg/l TDS in drinking water. Secondary standards are recommended guidelines for contaminants that may cause cosmetic or aesthetic effects in drinking water. Different foodservice applications require different levels of TDS. Steam applications require water with very low TDS to prevent heavy scale accumulation that could damage or destroy the equipment, while fountain beverage applications are fine with TDS of up to 500 ppm because scale typically does not pose a problem since there is no energy being applied to the water. Some Everpure RO systems provide a “blend” feature that allows raw water to bypass the RO membrane. Both the raw water and the RO water are filtered through a traditional taste & odor filter and then blended. This control of the quantity of TDS allows the system to meet specific water specifications. For example, a coffee recipe may require water with a TDS of 150 ppm.

The Benefits of Reverse OsmosisReverse Osmosis is extremely effective at eliminating or substantially reducing a wide variety of contaminants, more than most all other types of treatment. Because Reverse Osmosis removes from 95%-99% of the total dissolved solids, it is often the best technology for obtaining clean water that is free of TDS and other contaminants. And because it is stripping water of damaging contaminants that can cause harm to equipment, it helps reduce operating costs.

RO systems are effective in removing excess salt and other dissolved minerals, taste and odor, heavy metals, microorganisms, nitrates and pesticides. Water treated by reverse osmosis has a noticeably cleaner and sparkling appearance and allows subtle flavors in foods and water-based beverages to come through.

The Drawbacks of Reverse Osmosis
Despite their effectiveness, RO membranes are subject to a number of factors that make them susceptible to loss of function. The amount of contaminants, size and type of equipment, and system pressure all can contribute to buildup of material on the membrane. In addition, disinfectant chlorine can attack some membranes. To prevent this, RO systems typically include a carbon prefilter to reduce chlorine that can damage the membrane. A sediment prefilter also is used to prevent fine suspended particles in the source water from permanently clogging the membrane. Larger commercial systems sometimes soften the incoming water or add scale inhibitors to preserve membrane porosity.

Reverse Osmosis systems are also more expensive than traditional filtration, and require more maintenance. And, because a portion of the water supply must be used to flush the contaminants to drain, there is a waste factor that can represent a significant portion of the total water use. Another drawback to Reverse Osmosis is it produces clean water at a slow rate, and therefore requires the use of a holding tank so water is available during peak usage periods.

Scale Reduction

What is Scale?

As rainfall descends, it picks up CO2, which makes water slightly acidic. By the time it reaches the earth, it is now a natural solvent. As it seeps down to the underground aquifers, it dissolves mineral along the way, becoming “hard.” Hard water is generally concentrated with four hard minerals: calcium, magnesium, carbonate, and sulfate. Every water supply has some dissolved mineral content.

How Does Scale Form?
When energy is applied to hard water, the minerals can drop out of the solution and settle on surfaces. This is called scale, the most common of which is limescale. These minerals can form a hard crust that can cause many problems with equipment, from clogging to increased energy requirements.

To understand the process that allows dissolved mineral content to rebuild solid rock, it is important to understand the condition of pH. The scale for pH is measured from 0.0 to 14.0, with 7.0 as a perfect neutral. In general terms, water supplies with a pH below 7.0 have a greater acid content and tend to dissolve rock into minerals. Water supplies with a pH above 7.0 have a lower acid content and tend to build mineral scale.

There are two key conditions for scale formation:

The pH level must be neutral or above
There must be an energy transfer, cooling or heating, to act as a catalyst.

How Does Scale Affect Water-using Equipment?
Mineral deposits such as limescale create major problems for foodservice operators with ice, coffee, espresso, steam and warewashing equipment. Mineral scale can clog tubing and small orifices, coat heating and cooling elements, and result in increased detergent usage. Scale also causes reduced energy transfer and efficiency loss, resulting in increased energy demands for cooling or heating, and increased operating costs.

Many water-using appliances, from coffee brewers to ice makers, are susceptible to limescale build-up. Steamers and combi ovens are among the most susceptible. As water boils and evaporates, minerals remain and become concentrated. Because of these high concentrations, steamers can require frequent deliming—an acid cleaning process that removes mineral scale. This process is harsh to the equipment surfaces and decreases equipment life.

Freezing water can also cause scale to form. Commercial cuber-type ice makers require more service to correct scale build-up than any other equipment commonly used in foodservice. Like steamers, commercial icemakers leave a high concentration of minerals as most of the water becomes ice. The resulting residue is a murky mixture full of sediment and growing crystals that restricts tubes, fouls pumps, clogs orifices, scores valves, and causes ice to hang in clumps.

Fortunately, scale growth can be reduced by adding small amounts of polyphosphates to water. Polyphosphates are completely safe and nontoxic, and many occur naturally in foods or are added during processing. They are also used in the treatment of drinking water to combat corrosion and scaling. Most scale-producing situations can be resolved more effectively with a point-of-use water treatment system that couples fine filtration and a polyphosphate feed. Fine filtration reduces particles that act as nucleation sites for scale formation. These particles speed up the scaling process and can add as much as 60 percent to the weight of the scale, depending on the particles in the source water. Everpure produces many systems meeting these specifications for home use, vending and office applications, and commercial foodservice.

Types of Scale
The appearance of scale varies infinitely and depends on the impurities that are present in the water. For example, pure limescale is pure white, but sediment and turbidity due to dust, dirt and mud may color it.

Treating Scale
The most common methods for reducing scale are:

Polyphosphates
Reverse Osmosis
Softening

Slime Reduction

What exactly is slime? It is a type of mold or fungus that accumulates from bacterial growth on surfaces that are constantly exposed to water droplets and warm temperatures. If machine surfaces are exposed, not often wiped clean, or the machine is not sanitized regularly, you will experience bacteria and mold growths in the moist, cool environment of your ice maker.

Slime itself does not cause foodborne illnesses, per say, but it can cause ice to have an objectionable taste or odor. In addition to negative impacts on quality of the drinks you serve your valued customers, slime in commercial ice machines is one of the leading causes of low ice production and machine failure.

To prevent slime and keep your ice making equipment running efficiently, it’s important to keep interior ice machine surfaces clean and routinely sanitized. Pentair offers a unique solution in its carbonless Everpure SI Series Cartridges which feature valuable slime reduction and scale inhibition capabilities to attack the problem from the ingredient water side. These filters do that job well and also help minimize the frequency of ice machine cleanings, saving you the labor, downtime and expense involved in the process.

Softening / Ion Exchange

Why Soften Your Water?

The Ion Exchange Process Softening is the process of ion exchange. The ions in hard minerals (calcium and magnesium) are exchanged with ions of “soft” minerals such as sodium, which do not produce the hard scale that can damage foodservice equipment.

Water softener systems consist of two tanks: a resin tank and a brine tank. The resin tank contains a bed of negatively charged cation resin beads that are coated with sodium (Na+). As hard water passes through this bed, the positively charged calcium (Ca++) and magnesium (Mg++) ions are attracted to and adhere to the resin, causing the sodium ions to release into solution. The calcium and magnesium in the water has now been exchanged for sodium. Since the sodium in the water is harmless to plumbing and equipment, the “softened” water is now ready for use by the operation.

During the exchange process, the sodium charge eventually depletes. When near depletion, the softener is regenerated to recover the exchange capacity. To remove the calcium and magnesium from the beads, high concentration sodium solution from the brine tank is drawn through the resin bed. The sodium ions in the solution displace the calcium and magnesium ions, releasing them back into the solution. The sodium in the water has now been exchanged for the calcium and magnesium. These hardness ions are then flushed down the drain.

It’s important to understand that a water softener does not filter water, it only exchanges hard ions for soft ions. For removal of dirt, chemicals and organics, a filtration system should be used.

Water Grains / Gallon Mg / l or ppm

Soft                          < 1.0                    0 - 17.1
Slightly Hard          1.0 - 3.5              17.1 - 60
Moderately Hard     3.5 - 7.0              60 - 120
Hard                        7.0 - 10.5           120 - 180
Very Hard               > 10.5                 180 +

Are All Applications Suitable for Softened Water?

Generally softened water is recommended for:

Espresso

Iced tea
Warewashing

Espresso machines boil water at a very high temperature and pressure, much more so than coffee brewers. Because of this, hard water will create scale at a very fast rate in espresso machines. Normally softened water causes over extraction of the coffee grounds, which is why it is not used with coffee brewers. However, because extraction time is so short with espresso, it does not cause the same problem. Hard water can cause iced tea to become cloudy. With warewashing applications, hard water causes spotting on glassware and excessive detergent usage.

Water softening is not recommended for:

Ice making

Coffee and tea brewing
Fountain beverages

Soft water can slow the freezing process in ice making. With coffee and tea brewers soft water can over extract the oils and flavors in the coffee grounds or tea leaves. The major bottling companies have also asked water treatment professionals to avoid the use of water softeners with fountain beverage equipment because softened water can affect the taste profile and cause excessive foaming.

What a Water Softener Does Not Do. Water softeners are cation exchangers meaning they will exchange positive ions such as calcium, magnesium, iron, copper, zinc, manganese, and other metals. Water softeners to not filter water, they merely exchange hardness ions for sodium ions. Sediment, chemicals and organics that can affect the appearance, taste and odor of your water are not affected by softening your water. For these, you should consider an Everpure filtration system, or an Everpure reverse osmosis system.

TDS Reduction

TDS, which stands for Total Dissolved Solids, refers to the amount of organic and inorganic dissolved substances that may be found in your water, such as minerals, metals and salts. Essentially, it is everything present in water other than pure H2O and suspended solids. TDS can be from natural sources such as dissolved rock or from man-made chemicals such as Volatile Organic Chemicals (VOC’s).

Often, a major component of TDS is hard and soft minerals. Because water is naturally slightly acidic, as it travels through the rock formations in the ground a small quantity of rock is dissolved into a liquid form. These dissolved minerals include calcium, magnesium, chlorides and silica.

Total Dissolved Solids are measured as parts per million (ppm), and it is worth noting that Federal drinking water standards recommend a limit of 500 ppm. It is also worth noting that the national average is probably in the range 300-350 ppm for the United States. In some coastal areas and areas with heavy limestone deposits TDS can be well over 1400 ppm. The lower the TDS, the more pure the water is.

The concept of parts per million may be difficult to visualize, but the same measurement can be stated as “milligrams per liter” when you discuss mineral content. If you evaporate one liter of water with mineral content and collect the dried mineral powder, it can be weighed in milligrams. A water sample with 50-70 ppm will contain enough dried mineral content to equal the size and weight of about one generic aspirin tablet.

What are the effects of TDS and how can it be treated?

TDS is a secondary drinking water standard by the USEPA which means it generally is not a health hazard. However, high TDS creates a variety of problems for foodservice operations:

It affects the taste of water and beverages, and can mean that sodium, calcium, chloride, and magnesium may all be detectable in your final product. Depending on the quantities and combinations of the dissolved materials, water can taste alkaline (bitter), salty or metallic.

Hardness, normally a component of TDS, can create scale in equipment that heats or freezes water such as coffee brewers, ice machines and combi ovens.

It can cause your ice machine to produce fast melting, cloudy, soft ice.

High TDS can cause iced tea to become cloudy after brewing.

It will reduce the carbonation in your fountain beverages.

During coffee and espresso brewing, solids are extracted from the coffee grounds. Without consistent TDS levels the quality of coffee and espresso can range greatly from strong and bitter to weak and underdeveloped.

With nearly all foodservice equipment, some TDS is desired, depending on the application. The mineral content in TDS is what gives water flavor. Without it, water would taste flat (this is one reason why straight RO water is not used for beverages). For coffee and espresso, a TDS of 150-200 ppm is best for proper flavor. For drinking water and fountain beverages, a TDS of up to 500 is acceptable. For boiler-based steam ovens, TDS should be kept very low, less than 100 ppm (but not too low or the probes in the boiler won’t be able to detect the water levels). Check your steam warranty for the recommended TDS levels.

Many types of dissolved material will pass through mechanical and carbon filtration, and often require treatments such as reverse osmosis or water softening.

Ultrafiltration

Ultrafiltration (UF) is a type of membrane filtration in which hydrostatic pressure forces a liquid against a semipermeable membrane. A semipermeable membrane is a thin layer of material capable of separating substances when a driving force is applied across the membrane. Once considered technology viable only for desalination, membrane filtration is increasingly being used to remove particulates, natural organic material, bacteria and other microorganisms which can impart undesirable color, off-tastes and odors to your water. It also remove contaminants that can react with disinfectants to form disinfection byproducts (DBP) in drinking water, including trihalomethanes, haloacetic acids, bromate, and chlorite.

Ultrafiltration uses hollow fibers of membrane material and the feed water flows either inside the shell, or in the inside space of the tubular-shaped fibers. Suspended and dissolved solids of high molecular weight are retained, while water and low molecular weight solutes pass through the membrane. Ultrafiltration is not fundamentally different from reverse osmosis, microfiltration or nanofiltration, except in terms of the size of the molecules it retains. When strategically combined with other purification technologies in a complete water system, UF is ideal for the removal of colloids, viruses, bacteria, and microorganisms larger than the membrane pore size from water. Its primary removal mechanism is size exclusion, though surface chemistry of the particles or the membrane may affect the purification efficiency. UF can be used as pretreatment for reverse osmosis systems or as a final filtration stage for deionized water.

The primary advantages of ultrafiltration:

Constant, high quality water production.

Operational convenience: the procedure adapts automatically to the quality of the raw water.

Does not use chemicals.

No risk of dangerous by-products.

Cost-effective to operate.

Compact footprint.

Environmentally-friendly technology.

Water Boost

High water pressure flowing to the filter system, which extends the life of the cartridges.

Chlorine in the bladder of the water boost to prevent growth of algae and bacteria.

There are available water pressure boosting and regulating solutions that can help you address pressure boost requirements in your operation.

Water Testing & Analysis

By the time water reaches a restaurant, it has developed a unique chemistry that can be surprisingly diverse and highly complicated. As water descends as rainfall, it picks up CO2 that gives it a slight acidity. When it reaches the earth, it either descends to underground aquifers or drops into lakes and rivers.

Water it is a natural solvent, so when it percolates down to underground aquifers, it literally dissolves rock. These dissolved minerals, known as Total Dissolved Solids (TDS), are what create scale in foodservice equipment. Total Dissolved Solids can be combinations of “hard” minerals such as calcium and magnesium, or “soft” minerals such as sodium.

When water ends up in lakes and rivers, it can pick up suspended solids such as silt and clay, and organic matter such as bacteria, algae and cysts.

Water from underground or from surface water can both contain chemicals from human contamination such as Volatile Organic Compounds (VOC’s) and nitrates, and gasses from fermentation of plant matter or by products of bacteria growth.

Municipal water companies can draw water from aquifers or from surface water—sometimes from both. In order to provide your business and home with safe tap water, it is disinfected with either Chlorine or Chloramine.

Finally, as water travels to your faucet or equipment, it can pick up metal particles from corroded pipes.

So by the time it has made its way to your coffee brewer or ice machine, it can contain calcium, magnesium, silica, chlorides, iron, copper, sodium, sulphates, carbonates and bicarbonates, hydrogen sulfide gas, cysts, bacteria, dead plant matter, ferric iron, silt, clay, chlorine or chloramine. Most of this is not visible. The concentrations of these contaminants vary depending on:

Where you live. Some areas have large limestone deposits that create hard water. Other areas, such as Hawaii, have serious problems with silica. In the colder states salt used on roads for de-icing can leach into water supplies.

Whether your water comes from underground aquifers or from surface water. Water from aquifers tends to be hard because it dissolves minerals as it travels through the rock. Water from lakes and rivers tends to have more organics, so as algae bloom and die, your water can become discolored (tannins) or develop unpleasant odors.

The disinfecting chemicals your water treatment plant uses. It’s easy to recognize water treated with chlorine and chloramine as it will have a distinctive swimming pool smell and taste. Chloramine is chlorine with a small amount of ammonia added. The ammonia slows the dissipation of the chlorine, so the disinfectant stays in the water longer.

Because water can have so many contaminants, it can create serious issues with not only the taste, odor and appearance of your beverages and ice, but also with the performance of your water-using equipment. Chlorides can cause corrosion to plumbing and equipment parts. Hydrogen sulfide gas can give water a strong rotten egg smell. Sodium can cause fountain beverages to lose their fizz and ice to be soft.

Water with high levels of calcium and magnesium can create scale. This often looks like a hard white chalky material although it can take on many colors and textures. Scale is formed when energy is applied to water. For example, when water is converted to steam, the minerals drop out of solution and cling to nearby surfaces. This can build up over time, and be difficult to remove. Scale that is ¼” thick can reduce energy efficiency by 28.5 percent. Your operating costs go up, and your equipment breaks down more.

This is why it’s important to test your water. By determining your water’s unique characteristics, the right water treatment can be applied. If you have a strong chlorine taste and smell, a good carbon filter should solve the problem. If your hardness is higher than it should, you can apply a water softening system. If your Total Dissolved Solids are excessive, then you will need a reverse osmosis system.

By bringing your water to the standards established for foodservice operations, you are ensuring that your customers’ beverages and food will taste as they should, and your equipment will require fewer maintenance calls and last longer.

General Solutions

Water impacts customer satisfaction.

Your customer’s first and last impression of your operation is often the beverage you serve them. If the taste and odor of your fountain beverages and coffee, or the appearance of your iced tea or drinking water is not as it should be – it will be noticed.

Water impacts your profits.Water travels with a lot of unwanted chemicals, sediment and dissolved minerals that can affect equipment performance and operating life.

Pentair Everpure is a global leader in foodservice filtration solutions for chlorine taste & odor reduction, chloramines reduction, scale inhibition, and a wide range of other undesirable contaminants. If you do not find what you were looking for in those solution-specific sections of our site, you are likely to find it here.

Need further assistance? Please call us at 25720762 (CY only) or email the team at info@daskservices.com .

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