Simple Solutions Can Make Water Safer:
An independently water filter can be a good temporary fix for your kitchen faucet.
Some filters aim to produce clearer, better-tasting water, while others work to remove contaminants that could affect your health.
This guide will help you determine what type of filter might be right for your home.
Select the Right Filter:
Most of the methods of water treatment methods discussed below are Point Of Use (POU) devices. POU methods treat water at the point where is is used - frequently at the kitchen sink. Only the water that is actually used for drinking, cooking, beverage preparation, etc. is treated. This has the advantage of economy - only a few hundred gallons of water need to be treated per year instead of many thousands if all of the water entering the home were to be treated.
Point Of Entry (POE):
or whole house water treatment (where all water entering the home is treated) is indicated when the water has problems that affect all areas of the home. The most common example is a water softening ion exchange system that removes calcium and magnesium ions (and some other ions) from the water. Hard water, while quite healthy to drink, can cause scale buildup in pipes and on fixtures, interfere with the effectiveness of soap, and shorten the life of appliances, like dish washers and hot water heaters. Other POE water treatment systems are designed to remove iron and manganese, adjust pH levels, add chlorine or other disinfectant, etc. People using water from a private well, spring, or surface source are most likely to require POE treatment. A high quality POU treatment system should also be considered if you have a well or use water from a spring or surface source, because each type of POE treatment generally removes only one contaminant type (the one or two POE treatment methods someone might use would only remove the most obvious, annoying, or dangerous contaminant(s)). Other contaminants that might be present like lead (from the home's plumbing and pipes) and chlorine residue (if the water is disinfected) would best be removed by a POU device.
General:
Household water filters generally fall into one of two categories: point-of-entry units, which treat water before it gets distributed throughout the house; and point-of-use units, which include countertop filters, faucet filter.
Brief Introduction to Filtration Media:
- What is KDF?
Kinetic Degradation Fluxion (KDF) is a high-purity copper-zinc formulation that uses a basic chemical process known as redox (oxidation/reduction) to remove chlorine, lead, mercury, iron, and hydrogen sulfide from water supplies. The process also has a mild anti-bacterial, algaecitic, and fungicitic, effect and may reduce the accumulation of lime scale.
Chemical properties of KDF include its alleged ability to:
- Remove chlorine (actually changes free chlorine to a less active form)
- Kill algae and fungi
- Control bacterial growth in the filter
- Remove hydrogen sulfide, iron, lead, cadmium, aluminum, mercury, arsenic and other inorganic compounds
- Partially reduce hardness
The advantages of KDF filters include:
- KDF is the only filter medium I am aware of that allegedly removes contaminants from running hot water (unlike carbon filters where hot water can release trapped contaminants into the water stream). This makes them ideal for use in the shower.
- The filters change the free chlorine some people are allergic to into a form (zinc c chloride) that is much more easily tolerated
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KDF process media is used in pre-treatment and primary treatment applications to supplement or replace existing technologies in order to extend system life and to reduce heavy metal contamination, chlorine and hydrogen sulfide. It is often combined with other technologies to achieve superior overall results. Because of its effectiveness at higher water temperatures, it is often used on shower water filtration systems to remove chlorine and other contaminants.
The technology was developed by KDF Fluid Treatment, Inc. in the mid 1980s and was patented in 1987. KDF filter media meets EPA and Food and Drug Administration standards for levels of zinc and copper in potable water, and is certified by NSF International to its Standard 61 for drinking water
- What is activated Carbon Filters?
Activated carbon (AC) is particles of carbon that have been treated to increase their surface area and increase their ability to adsorb a wide range of contaminants activated carbon is particularly good at adsorbing organic compounds. GAC filters degree of effectiveness depends on the flow rate of the water and contact time with the water. If flow rate is excessive their efficiency could be as low as 0% and if the flow rate is slow their efficiency can match and or exceed those of different carbon forms.You will find two basic kinds of carbon filters Granular Activated Carbon (GAC) and Solid Block Activated Carbon (SBAC).
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Contaminant reduction in AC filters takes place by two processes, physical removal of contaminant particles, blocking any that are too large to pass through the pores (obviously, filters with smaller pores are more effective), and a process called adsorption by which a variety of dissolved contaminants are attracted to and held (adsorbed) on the surface of the carbon particles. The characteristics of the carbon material (particle and pore size, surface area, surface chemistry, density, and hardness) influence the efficiency of adsorption.
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AC is a highly porous material; therefore, it has an extremely high surface area for contaminant adsorption. One reference mentions "the equivalent surface area of 1 pound of AC ranges from 60 to 150 acres (over 3 football fields)". Another article states, "Under a scanning electron microscope the activated carbon looks like a porous bath sponge. This high concentration of pores within a relatively small volume produces a material with a phenomenal surface area: one tea spoon of activated carbon would exhibit a surface area equivalent to that of a football field." ( estimates of surface area vary from different sources - RJ)
AC is made of tiny clusters of carbon atoms stacked upon one another. The carbon source is a variety of materials, such as peanut shells, coconut husks, or coal. An article about Activated Carbon states that "Activated carbon is one of the best tools which can be used to reduce risks to human health and provide an aesthetically pleasing product at reasonable cost."
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Activated carbon filter cartridges will, over time, become less effective atreducing contaminants as the pores clog with particles (slowing water flow) and the adsorptive surfaces in the pores become filled with contaminants (typicaly not affecting flow rate). There is often no noticeable indication that a carbon filter is no longer removing contaminants, so it is important to replace the cartridge according to the manufacturer's instructions. The overall water quality (turbidity or presence of other contaminants) also affects the capacity of activated carbon to adsorb a specific contaminant.
It is important to note, particularly when using counter-top and faucet-mount carbon filtration systems, that hot water should NEVER be run through a carbon filter. I have seen warnings about possible damage to the filter from hot water. Perhaps more importantly, hot water will tend to release trapped contaminants into the water flow potentially making the water coming out of the filter more contaminated than the water going in.
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Powdered activated carbon used in CB and PAC cartridges
| Fine granule carbon used in GAC cartridges
| Coarse mesh carbon used for industrial and municipal gravity water filters
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- What is Reverse Osmosis?
Reverse osmosis (RO) is the most economical method of removing 90% to 99% of all contaminants. The pore structure of RO membranes is much tighter than UF membranes. RO membranes are capable of rejecting practically all particles, bacteria and organics >300 daltons molecular weight (including pyrogens).
- How it work?
Natural osmosis occurs when solutions with two different concentrations are separated by a semi-permeable membrane. Osmotic pressure drives water through the membrane; the water dilutes the more concentrated solution; and the end result is an equilibrium. In water purification systems, hydraulic pressure is applied to the concentrated solution to counteract the osmotic pressure. Pure water is driven from the concentrated solution and collected downstream of the membrane. Because RO membranes are very restrictive, they yield slow flow rates. Storage tanks are required to produce an adequate volume in a reasonable amount of time. RO also involves an ionic exclusion process. Only solvent is allowed to pass through the semi-permeable RO membrane, while virtually all ions and dissolved molecules are retained (including salts and sugars). The semi-permeable membrane rejects salts (ions) by a charge phenomena action: the greater the charge, the greater the rejection. Therefore, the membrane rejects nearly all (>99%) strongly ionized polyvalent ions but only 95% of the weakly ionized monovalent ions like sodium.
- What is removes?
Reverse osmosis is highly effective in removing several impurities from water such as total dissolved solids (TDS), turbidity, asbestos, lead and other toxic heavy metals, radium, and many dissolved organics. The process will also remove chlorinated pesticides and most heavier-weight VOCs. Reverse osmosis and activated carbon filtration are complementary processes. Combining them results in the most effective treatment against the broadest range of water impurities and contaminants.
Reverse osmosis treatment process icon
- What is UF?
Utrafiltration or UF is a pressure-driven membrane separation process that helps removes particulate matter from aqueous solutions such as water. UF membranes typically have pore sizes in the range of 0.01 to 0.10 ¦Ìm and efficiently remove bacteria and most viruses, colloids and silt. The smaller the nominal pore size, the higher the removal efficiency. Most materials that are used in UF are polymeric and are naturally hydrophobic, such as polysulfone (PS), polyethersulfone (PES), polypropylene (PP), or polyvinylidenefluoride (PVDF).
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Typically, UF membranes will remove high molecular-weight substances, colloidal materials, and organic and inorganic polymeric molecules. Low molecular-weight organics and ions such as sodium, calcium, magnesium chloride, and sulfate are not removed by UF Membranes. Because only high-molecular weight species are removed, the osmotic pressure differential across the UF Membrane surface is negligible. Low applied pressures are therefore sufficient to achieve high flux rates from an Ultrafiltration membrane. Flux of a membrane is defined as the amount of permeate produced per unit area of membrane surface per unit time. Generally flux is expressed as gallons per square foot per day (GFD) or as cubic meters per square meters per day.
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Ultrafiltration UF membranes can have extremely high fluxes but in most practical applications the flux varies between 50 and 200 GFD at an operating pressure of about 50 psig in contrast, reverse osmosis membranes only produce between 10 to 30 GFD at 200 to 400 psig.
- POU Water Purifier
- Revese Osmosis Water Purifier - Structure & flow chart(50G)
1
| Solenoid valve
| 7
| RO membrane
2
| PDF filter
| 8
| Post-active carbon filter
3
| Granular activated carbon filter
| 9
| High voltage switch
4
| Fine active carvon filter
| 10
| Pressured tank
5
| Water inlet valve
| 11
| Backflush solenoid valve(Bullet valve)
6
| High pressure pump
| 12
| Concentrated water regulating valve
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- Working Principe
- Filtration Stages
Our Fresh Water Type Purifier adopts US¡¯ high-tech reverse osmosis process. Tap water is going through 3 stages pretreatment, which prolong the life of RO membrane.
- Stage: Osmonics 5 micron 10" high-capacity polypropylene sediment filter ~removes dust, particles, and rust.
- Stage: Granular activated carbon- gets rid of unpleasant chlorine, tastes and odors, cloudiness and colors.
- Stage: Extruded Carbon Block 5 micron 10" ~removes any residual chlorine, tastes and odors, plus compounding pre-filters' efficiency and extending membrane's life.
- Stage: High Rejection TFC reverse osmosis membrane .0001 micron ~ heart of the r.o. system, produces drinking water at a rate of 50 gallons per day.
- Stage: Post-activated carbon- removes any possible residual tastes and odors from the tank.
- Feature
Ultra Safe, Ultra Pure : The RO that guarantees ultra safe and clean drinking water for your family
Automatic shut-off: System shuts off automatically when tank is full and system start automatically when tank level is low without wasting any water.
- Filter cartridges Replacement:
To ensure normal operation of the machine and to make sure you enjoy the pure security water,
Filter cartridges need be to replaced periodically.
Water source: Tap water ( turbidity between 2 to 10 )
Filtration stages
| Item
| Replacement cycle
1st Stage
| Polypropylene sediment filter
| 3~6 month
2nd Stage
| Granular activated carbon
| 6~12 month
3rd Stage Extruded
| Carbon Block 5 micron 10
| 6~12 month
4th Stage reverse
| osmosis membrane(RO membrane)
| 24~36 month
5th Stage
| Post-activated carbon
| 6~12 month
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If the water source is ground water with high iron content, the replacement cycle of filter cartridge is the following. Refer to the following table.
Water source: ground water with high iron content
Filtration stages
| Item
| Replacement cycle
1st Stage
| Polypropylene sediment filter
| 2~5 month
2nd Stage
| Granular activated carbon
| 5~11 month
3rd Stage
| Extruded Carbon Block 5 micron 10
| 5~11 month
4th Stage
| reverse osmosis membrane(RO membrane)
| 12~24 month
5th Stage
| Post-activated carbon
| 5~11 month
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In addition, microorganisms and bacteria is very easy to breed in the summer causing bad odor. It is suggested that replace the filter cartrage of before treatment to prevent the growth of bacteria.
The above replacement cycle is just for reference, because the city tap water quality is different in different city.
- Troubleshooting - Sign of Replacement of filter cartridges
- Producing pure water is too slow: pre-filter or reverse osmosis membrane filter block
- Producing pure water is too quick (less than one hour a barrel): reverse osmosis membrane damage.
- Poor taste and odor: Post activated carbon filter is needed to be replaced.
- The rejection rate of RO membrane is less than 75%: The RO membrane need repacing. embrane
Rejection rate of RO membrane is calculated as
RO membrane Rejection Rate = (raw water TDS values - pure water TDS value) ¡Á 100% raw water TDS value.
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