Water Filtration and Shower Water Filters

Water Filters

If you have immune system concerns, you should pay special attention to the substances you ingest, particularly water. Some estimates have placed drinking water towards the top of the list in terms of environmental concerns posing a hazard to the health of the general population. Many sources of drinking water have been polluted by a wide range of contaminants. The most common among these is bacterial and microbial content. Having your water treated by municipal filtration systems doesn't necessarily mean your water is safe from these threats. There have been recent documented cases of serious outbreaks of disease caused by Cryptosporidium in several large cities in the last couple of years alone. It is incumbent upon the individual with special vulnerabilities to protect their own health; it is long past the time when reliance on governmental entities to treat and/or monitor our water quality was a sufficient precaution against serious health risks.
People with immune systems that are weakened by AIDS, chemotherapy or transplant medications are more vulnerable to microbial contaminants in drinking water such as Cryptosporidium. Cryptosporidium is a microscopic parasite that lives in the intestine of infected animals and humans. It passes in the stool in its dormant oocyst form. The oocyst is protected by an outer shell that allows it to survive outside the body for long periods of time and makes it very resistant to chlorine-based disinfectants. It occurs mainly in surface water sources, such as lakes, streams and rivers. In healthy adults, Cryptosporidium can cause illness, but for people with weakened immune systems, it can cause severe illness and even death. Those who wish to take extra measures to avoid waterborne cryptosporidiosis can bring their drinking water to a boil for a full minute. Boiling water is the most effective way of killing Cryptosporidium. As an alternative to boiling water, people may take the following measures: Use a point-of-use filter Consider using point-of-use (personal use, end-of-tap, under sink) filters that remove particles one micrometer or less in diameter. Filters that use reverse osmosis, those labeled as "absolute one micron filters," or those labeled as certified by an American National Standards Institute (ANSI) - accredited organization to ANSI/NSF Standard 53 for "Cyst Removal" provide the greatest assurance of removing Cryptosporidium. As with all filters, follow the manufacturer's instructions for filter use and replacement.
You can use bottled water; however there is little assurance that the bottler has taken the necessary precautions to treat water adequately. One blind study of a number of bottled water companies found several instances where the water in the bottle was exactly the same as tap water. Check the label or call the bottler to find out how bottled water is treated, although quality can vary from bottle to bottle even with the bottler's assurance in hand. The following bottled water treatments protect against Cryptosporidium: reverse osmosis, distillation, ultraviolet light, or filtration with an absolute one micron filter. Bottled waters derived from protected well and spring water sources are less likely to be contaminated by Cryptosporidium than those containing untreated municipal drinking water from less protected sources such as rivers and lakes. If you have a contaminated private well, have special health needs, or in an emergency situation such as a flood, boil water for one minute to kill microbes (or three minutes at altitudes greater than one mile) and place in a clean, covered container. In these cases, any bottled water is better than the contaminated water supply.
Those who choose to take these precautions should remember that they can be exposed to waterborne pathogens through water used for brushing teeth, making ice cubes, and washing fruits and vegetables - not just through water they drink. Though less of a threat to compromised immune systems, bathing and shower water can be a concern as well. Although shower filters, at best, only take out chlorine and volatile organic compounds (VOCS), these can introduce sufficient hazards to bathing water to cause serious illness to those with vulnerable immune systems. It is advisable to use a shower filter that contains both KDF and GAC media in order to address the most contaminants possible. Unfortunately, usual carbon block and most GAC do not tolerate hot water well and this limits the efficiency of these systems. We recommend using your shower filter to fill the bathtub as well. It is the easiest way to get good quality bathing water as systems made specifically for tub faucets are the least efficient of all.
Another concern is the use of reverse osmosis systems. While you can get highly purified water with these systems, the product is basically inert and contains no natural mineral content. Increasingly, the water quality and health literature suggest that natural mineral content is one of the most healthful aspects of drinking water and should be retained. People with immune disorders probably benefit as much or more form these minerals and every effort should be made to utilize fully mineralized water for drinking. A high quality carbon block filter or ultra violet treatment gives the best filtration while keeping minerals in the water.
A water filter is composed of a screen with many microscopic holes. The smaller the holes, the more particulates the filter can remove. Filter holes are measured in microns. (The period at the end of this sentence is 500 microns.) When considering filter size, look for an absolute (the largest hole), not a nominal (the average hole), rating. EPA and CDC recommend an absolute one micron filter (or one labeled for cyst removal) to remove Cryptosporidium. Some contaminants and their size in microns:
Guardia lamblia - 8 to 12 microns; Cryptosporidium parvum - 4 to 6 microns; Bacteria (such as E. coli and salmonella) - 0.2 to 4 microns; Viruses - 0.004 to 0.1 microns (Generally, only a few filters, such as ultrafilters and reverse osmosis, have holes small enough to assure removal of all viruses. However, viruses can be killed using a disinfectant).
These are some of the issues to take into consideration when planning to address water quality at your point of use. It is highly advisable to get a water quality report from your local water system. They are required by law to provide this information. You can find many of these reports online as well. It is important to note that the standards established are not necessarily highly correlated with the threshold for health risks. In many cases, we don't know what safe amounts of these substances actually are. So, if there is any detectable presence of certain contaminants, beware in advance.

Shower Water Filters

Shower water filters are an essential component to any complete home water filtration system. A shower water filter allows you to enjoy a warm and relaxing shower, without the potential risk of exposure to harmful elements found in standard tap water. Chlorine is one of the biggest problems found in normal tap water. If your body is continually exposed to chlorine during a shower, it can lead to problems such as dry skin, irritated eyes or color distortion of the hair. This is due to the fact that chlorine strips the natural protective oils from the skin and hair, which leads to the excess dryness. If the chlorine is filtered out of the water, the skin and hair will greatly benefit. Removing chlorine can also be beneficial for individuals suffering from asthma and allergy sufferers, as inhalation of chlorine vapors can complicate those conditions. Showering with unfiltered tap water can be compared to spending ten to twenty minutes in an extremely chlorinated pool everyday. The most well-known shower water filter is the Aquasana Shower Filter, which retails for sixty to eighty dollars, depending on where it is purchased.
Shower waters filters can be easily installed in a few minutes. Once the water filter is properly installed, it provides healthy, chemical free water for showering. The best feature of the shower filter is its efficiency in removing chlorine from the water. It also greatly reduces harmful VOCs, which are the same harmful substances found in paints and pesticides. The filter also enhances the pH balance, which creates an overall healthier showering environment.
Most shower filters have an average life span of six months or ten thousand gallons. The filter can handle operating temperatures of 115 degrees, which is more than ample, as most average shower temperatures are 100 degrees. The filter fits well on the head of the shower. Most filters use two stages to purify the tap water. The first stage of the filter system removes all chlorine and improves the pH balance. The shower filter system brings the pH of the water to 7.5. This is accomplished by using a natural copper and zinc mineral media, which is called KDF-55D. KDF-55D removes any acidic components in the water, while retaining helpful trace minerals. The second stage of the filtering process employs a carbonized coconut shell media, which is responsible for the task of removing any synthetic chemicals and VOCs.
Most shower filters come with an adjustable pressure shower head which prevents any loss of water pressure. The filter systems are also compatible with most standard shower heads and hand held shower heads. In addition to providing health benefits, shower water filters also remove limestone, marble and other hard metals from the tap water. This helps to prevent scaling and hard water deposits in the shower or bathtub.

Manufacturing of Papers

Preparation of the fibres

The material to be used for making paper is first converted into pulp, a concentrated mixture of fibres suspended in liquid. The source of fibre is often natural (softwood or hardwood trees or other plants) or recycled, such as old corrugated boxes, newsprint, or mixed paper.
When best sheets materials are used to make paper, it is usually necessary to break down the lignin inside of the plant's cell walls. This is done via a chemical process, such as the Kraft Process. These processes are not needed when breaking down recycled fibres, as the lignin has already been removed from the source material. If the lignin is retained in the pulp, the paper will yellow when exposed to air and light.
Pulp that has been broken down mechanically is often known as "groundwood pulp." The mechanical process to break down wood chips into pulp requires no chemicals. Since the lignin is not removed from mechanical pulp, yields are relatively high, approximately 90-98%. However, due to the aging issues indicated above, mechanical pulp is most often used for newspapers and other non-permanent goods.
Pulp that is broken down chemically is known as "chemical pulp." The main purpose of a chemical pulping process is to break down the chemical structure of lignin and render it soluble in a liquid (most often water) so it may be washed from the remaining fibres. Removing the lignin from wood chips also serves to break them apart into the fibres that compose pulp.
Recycled fibres do not need to be pulped in the conventional sense. These fibres have already been treated once, so instead they need a more gentle process to break the fibres apart while preserving their integrity.
Once the fibres have been extracted, they may also be bleached, dyed, or have additional ingredients added to alter the appearance of the final product. For example, Kaolin (or calcium carbonate) is added to produce the glossy papers typically used for magazines.

Sheet formation

The pulp mixture is further diluted with water resulting in a very thin slurry. This dilute slurry is drained through a fine-mesh moving screen to form a fibrous web. A watermark may be impressed into the paper at this stage of the process. This mark is used on paper currency and other things. This moving web is pressed and dried into a continuous sheet of paper.
In the mould process, a quantity of pulp is placed into a form, with a wire-mesh base, so that the fibres form a sheet on the mesh and excess water can drain away. Pressure may be applied to help remove additional water. The paper may then be removed from the mould, wet or dry, and go on to further processing.
Most mass-produced paper is made using the continuous Fourdrinier process to form a reel or web of fibres in a thin sheet. When dried, this continuous web may be cut into rectangular sheets by slicing the web vertically and horizontally to the desired size. Standard sheet sizes are prescribed by governing bodies such as the International Organization for Standardization (ISO).

Drying

After the paper web is produced, the water must be removed from it in order to create a usable product. This is accomplished through pressing and drying. The methods of doing so vary between the different processes used to make paper, but the concepts remain the same.
Pressing the sheet removes the water by force. Once the water is forced from the sheet, another absorbant material must be used to collect this water. On a paper machine this is called a felt (not to be confused with the traditional felt). When making paper by hand, a blotter sheet is used.Drying involves using air and or heat to remove water from the paper sheet. In the earliest days of papermaking this was done by hanging the paper sheets like laundry. In more modern times, various forms of heated drying mechanisms are used. On the paper machine, the most common is the steam-heated can dryer. These dryer cans heat to temperatures above 200ºF and are used in long sequences of more than 40 cans. The heat produced by these can easily dry the paper to less than 6% moisture.

Kinds Of Air Filters & Air conditioning

Kinds of Air Filters

There are basically only two kinds of processes to make healthy air in your home: first, air cleaners, i.e., those that remove particles, odors and volatile organic chemicals (gases) from the air by entrapment, and second, air purifiers, those that destroy bacteria, viruses, odors and volatile organic chemicals (gases). But, you're right, there is more than one kind of method to do each of these processes. In a nutshell, here they are:

PROCESS 1:

FILTERS TRAP PARTICLES, ODORS AND GASES

There are basically two kinds of filters.
The first is media, or mechanical filters.

1. HEPA Filters Remove Allergens
A hospital grade HEPA (High Efficiency Particulate Air) filter is the most efficient mechanical filter for removing small particles, including allergens so small that they can only be seen with a microscope (0.3 microns or larger). Pollen, mold, fungal spores, dust mites, cockroach dust, tobacco smoke and bacteria are but a few examples.

2. Pre-filters Remove Larger Particles
A pre-filter removes particles from the air larger than a HEPA filter's smallest sizes, extending the life of the HEPA filter and protecting the gas absorbing media from dust coating and fouling.

3. HEGA Filters Remove Odors and Gases
A HEGA (High Efficiency Gas Accumulator) filter was designed for the British military for their gas masks and is quite good for tobacco smoke removal, in addition to everyday household odors and gases.

4. Activated Carbon Filters Remove Odors and Gases.
Granulated charcoal, which has been heated, results in a highly absorbent carbon, which is used for purifying gases by adsorption and deodorization. To do a great job you need a large amount of high quality activated carbon.

5. Zeolite Filters Remove Odors and Gases.
Zeolite is a natural mineral that is found in cavities in basic volcanic rocks. Bonded to polyester it has the ability to filter molecular-sized particles of volatile organic compounds (gases), especially pet odors and urine.

The second type of filter is electronic.

1. Negative Ion Filters Cause Particles to Clump, Fall on the Floor / Surfaces.
Negative ions energize, improve sleep and keep air fresh. Negative ions are generated with electricity. These negative ions cause allergens in the air, which have either a neutral or a positive charge, to be attracted to and stick to the negative ions (opposites attract). This forms clumps, which become heavy enough to fall to the floor or tables where they can be vacuumed or dusted off, instead of staying in the air where they can be breathed in.

2. Electrostatic Filters Remove Extremely Fine Particles from Gas Streams.
Electrostatic filters are both media filters and electronic filters. They are mechanical filters whose trapping ability is increased by an electrostatic charge generated by the flow of dry air through the media that attracts particles to the filter or screen. It is a gas phase filter used to remove extremely fine particles from gas streams, such as exhaust fumes, organic hydrocarbons, formaldehyde from particle board used in home construction, paint solvents, chlorine, cleaning chemicals and other fumes.

3. Electret Filters Remove Nanosize Particles.
The electret filter is an electrostatic filter whose charge is imposed at the time the filter is manufactured. The filter is composed of permanently charged electret fibers capable of collecting nanosize particles.

PROCESS 2:

AGENTS THAT DESTROY BACTERIA, VIRUSES, ODORS AND VOLATILE ORGANIC CHEMICALS (GASES).

1. Photocatalytic Oxidation Destroys Bacteria, Harmful Gases and Odors.
Photocatalytic oxidation kills and decomposes bacteria cells. It is a process where contaminants are oxidized through the interaction of ultraviolet radiation with a chemical or metal oxide catalyst. The titanium dioxide photocatalyst has been found to be more effective than any other antibacterial agent. It also reduces or eliminates polluted compounds in the air such as cigarette smoke, emissions of vehicle exhausts and power stations, and smog, as well as volatile compounds arising from various construction materials.

2. Ultraviolet Light Kills Disease-Causing Germs and Mold on Contact.
Ultraviolet light breaks organic molecular bonds, which means it destroys micro-organisms such as germs, viruses, molds and bacteria too small to be filtered out by filters. Although General Electric says that ultraviolet lights cannot kill molds, there are more than one kind of ultraviolet lights, the best of which CAN kill molds.

3. Ozone (Activated Oxygen) Kills Mold Spores and Active Molds, Bacteria, and Viruses.
Ozone (activated oxygen) is one of the most powerful sanitizers and deodorizers known. It eliminates odors and harmful substances at their molecular level. The fungi and molds that can grow in places that have experienced a flood can be removed with ozone. However, it can be very harmful to our lungs and other organs. The use of ozone in home air purifiers is a matter of great debate. Because of the potential risks involved, and because there are so many other effective ways to purify home air, we do not encourage the use of ozone at home.
All of these kinds of air purification methods need to be researched to find which is/are best for your needs. Don't ignore this and you can find a purifier that will be the best air purifier for you.

Air Conditioning

Air conditioning is not just about controlling the temperature; it also concerns purifying the air around you. This it does by means of a simple process of filtration. When exposed to unfiltered/unclean air continuously we, who breathe it in, might end up with difficult diseases like asthma or other allergies. Most Air-Conditioning units have a built in electronic air cleaners. These make use of the basic principle of electrostatic energy to drag out about 95% of the irritating elements we have floating around in the air around us and store it on plates in them. Cleansers like these are fixed in between the furnace and the air ducts so as to help filter the air indoors. The air in your home contains dust particles, fumes, allergens and a dozen other substances which simply won't go away no matter how much you clean or vacuum. When you switch on your AC this air will flow through the cooling system with the elements described above. It will then be dragged through a pre-filter in the electronic cleanser; this usually cleans it of the majority of irritating substances. Those that it does not are given an electric charge once they enter the filter. These charged particles are then drawn to the plates where they remain deposited until the plates are cleaned. Broadly speaking electronic air purifiers can be classified under two categories; electrostatic precipitators and charged media filters. Electrostatic precipitators collect particles on charged plates installed in them. In Charged Media Filters on the other hand the same substances are deposited on the charged fibers provided in the machine. The first kind of Purifiers are usually considered to be more effective than the latter. This is because Electrostatic precipitators supply dirt particles and other irritants in the air with a charge before depositing them; this causes a larger number of particles to be collected. Any common electrostatic precipitator can be expected to produce anywhere around 20,000 volts just to provide the particles with charge. There are two easy tests to find out how efficient an electronic air filter is. These are what is popularly called the weight-arrestance test and the dust-spot test. The first tests the machine's cleansing capacity in terms of the weight of the dirt the filter can remove. But this test will not confirm whether or not the machine is capable of removing small particles from your breathing air. The second test checks to see if the filter can catch substances between 0.3 to 6 microns, that is really minute substances and particles.

Air Cleaner Filters

Air filters trap small particles from the air, thus providing cleaner air. There are various types of air filters. The finer the filters, the better the filter system works, since it thus captures a larger percentage of airborne particles. There are three types of air filters.
HEPA Filters (high efficiency particulate arresting filters) are said to be the best because of their ability to trap up to 99% of particles down to 0.3 microns in size. However, very minute molecules, such as gas and tobacco smoke, are still able to pass through these filters. Pleated filters (also known as 'media filters') use the same materials as the HEPA filter, but are less effective because they are less tightly packed. Gas Phase Filters are less popular, since they only remove odors and fumes, but not any particulate matters.
There are a few guidelines that you need to follow before selecting the right type of air cleaner filters. The most important is to ensure that the filter has UL and Class II FDA approval, which simply means that the product is effective and in good condition. How effective is the filter? What are its capabilities in regards to removing substances and particles? To find out, see if the efficiency rate is in accordance with a 'True HEPA (high efficiency particulate air)' or better.
True HEPA means the filter must be able to capture at least 90% of all particles 0.3 microns or more in diameter. Check out the device's CADR rate (clean air delivery rate). The device should be able to cycle enough air to change every four to six minutes in the particular environment. The filter should be easy to clean and change. Also, compare the rates to replace a worn-out filter A good filter should not be too noisy.

Selection of Filter Media

DIFFERENT TYPE OF FIBERS


FIBER TYPE -- THERMOPLASTIC -- HYDROLYSIS

Polypropylene - Yes - No
Polyester - Yes - Yes
Co-Polymer - No - No
Homo Polymer - No - No
Nylon - No - Yes
Nomex / Conex - No - Yes
Rayton - Yes - No
P-84 (Polymide) - No - Yes
Glass - No - No
Teflon - No - No
Huyglass - No - No

FIBERS WHERE USED / WHERE NOT USED

Polypropylene :

Polypropylene is used exclusive in application where moisture is clearly a problem. It is limited by its low temperature resistance. At elevated temprature, rayton is selected for these same moist application

Polyster :

When Hydrolysis attack polyster it will weaken the media overall. Polyster is suitable when moisture is low.

Homopolymer :

Demonstrate good resistance to solvents, oxidizing agents, acid where the temperature is below 125-130 deg. cen. When moisture and chemistry attack polyster media, it looses its strength mainly due t break down of molecular structure of the polyster through hydrolysis.

Rayton :

Rayton fiber is problem solving material is high temprature application. It replaces Nomex when it fails due to Hydrolysis. This fiber can operate satisfactorily a elevated temperature . This can also replace Fiber glass some times when FG fails due to flex abrasion .This can also replace other material which can not withstand high temperature or chemistry /moisture.

Nomex :

Nomex is used in high temperature ( 204 deg.cen.) but in dry conditions Nomex is subject to Hydrolysis and will fail quickly in the presence of chemistry and moisture at elevated temprature.It s especially subjected to attack by sulfur oxides.

P-84 ( Polyamide ) :

P-84 is used I high temprature application ( 240 C ) but again dry condition .This s again subjected to hydrolysis .P-84 susbstituted fr fiber glass which can not take abrasion of continuous pulsing .It works better when there is no moisture and chemistry.

PTFE :

This is used when chemicals conditions are sever ,temprature resistance is also very good ( 240 C ) .PTFE does not have high level of abrasion resistance.

Glass :

This material offers outstanding performance in high temperature application ( 260 C ) . It is also resistant to most of the acid with major application being Hydrofluoric acid. Fiber glass has very poor flex abrasion resistance and it subject to quick failure if pulsed or cleaned vigorously.


FIBER -- CONT . OP. TEMP. - RESIST. TO ACIDS - RESIST. TO ALKALI - TENSILE STRENGTH
ABRASION RESISTANCE
Polypropelene - 90 - Excellent - Excellent - Excellent -
Good

Nylon - 110 - Fair - Excellent - Excellent
Excellent

Polyester - 150 - Good - Fair - Excellent
Excellent

Co-Polymer - 125 - Good - Fair - Good
Good

Homopolymer - 135 - Excellent - Fair - Good
Good

Nomex - 204 - Fair - Excellent - Excellent
Excellent

PPS (Ryton) - 190 - Excellent - Excellent - Poor
Excellent

Polymide - 200 - Fair - Excellent - Excellent
Excellent

Teflon - 260 - Excellent - Excellent - Fair
Poor

Cotton - 80 - Poor - Excellent - Good
Fair

Wool - 90 - Fair - Poor - Poor
Fair

Glass Fiber - 260 - Excellent - Fair - Excellent
Poor

Huyglass - 270 - Excellent - Fair - Excellent
Fair

Evaluating Filtration Media - A Comparison of Polymeric Membranes and Nonwovens

In early 1998, DuPont introduced an improved version of T-980, marketed under the name Tyvek® SoloFlo™
filtration medium. Engineered for a better balance of filtration properties, Tyvek® SoloFlo™ is made with a new
spinning technology (patent pending) that produces a reduced average fiber size and more even fiber size
distribution. The smaller fibers result in sheet layers with fewer thicker portions and a larger number of smaller
pores. A less cohesive structure, with larger void spaces between the layers in the plane of the sheet, allows more
gas and vapor to pass through the material. This gives Tyvek® SoloFlo™ a more open structure with a higher
porosity, significantly improved permeability and a 50% greater dirt-holding capacity (or filter life) than the
earlier T-980 style.

A Comparison of Filtration Media

At their simplest, filtration processes must meet objectives and be the most economical. Most processes are
chosen based on initial capital investment alone, with operating costs ignored. However, filtration media can
greatly affect the efficiency of any filtration process, as well as filtration cost. Therefore, filtration media should
be closely examined -- and evaluated -- before processes are chosen.
When choosing filtration media, end-users should first define their individual problems as carefully as possible,
particularly the desired flow (batch or continuous), required level of filtration, desired end-product (i.e., fluid,
solids or both), anticipated solids level(s), variability and operating conditions. Only after the process has been
defined and a filtration device has been selected, can the media selection begin. This requires both careful
planning and rigorous testing.
Filtration media can be evaluated against many criteria, but the four key criteria are: permeability, filtration
efficiency, filtration capacity (or life) and filtration costs.
Permeability
Meltblown nonwovens are considered the most permeable of today's filtration media, while microporous
membranes and spunbonded media (including Tyvek®) have decreased permeability. However, Tyvek®
SoloFlo™ exhibits air and water flow rates comparable to microporous membranes and begins to approach the
rates exhibited by typical meltblown media. The more open depth, finer fibers and asymmetrical structure of
Tyvek® SoloFlo™, as seen in scanning electron photo micrographs (SEMs), account for the material's high level
of permeability (see Figure 1: Top and cross-sectional views of Tyvek® SoloFlo™ at 200X magnification).
Figure 1: Top and cross-sectional views of Tyvek® SoloFlo™ at 200X magnification
Filtration Efficiency
When the filtration efficiency of media is compared, the positions of meltblown nonwovens and
microporous/PTFE membranes reverse, with membranes proving to be the most efficient, and meltblowns the
least efficient in a variety of applications. Typically, mean flow pore size (as determined by Coulter Porometer™
or Porous Materials Inc. Capillary Flow Porometer) can serve as an indicator of filtration efficiency, as in the
case of membranes versus most nonwovens.
Evaluating Filtration Media - A Comparison of Polymeric Membranes and Nonwovens
Submitted to Filtration & Separation Journal, Volume 35 No. 10, December 1998
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However, this principle does not hold true with Tyvek® SoloFlo™. Even though its mean flow pore size is close
to 5 microns, Tyvek® SoloFlo™ has demonstrated a high liquid efficiency at a nominal rating of 1 micron due to
the tortuous path of its fibers. In fact, AC Fine Test Dust (ACFTD) full-scale challenge tests have confirmed that
Tyvek® SoloFlo™ has higher Beta ratios (and therefore, higher efficiencies) than both meltblown and
spunbonded media, and approaches that of the 0.5-micron PTFE membrane laminate (see Figure 2: Results of
ACFTD testing on an Oberlin 2.4 ft2 production automatic pressure filter). Figure 3 shows that Tyvek®
SoloFlo™ approaches the efficiency of a 0.45-micron microporous membrane at about 4 microns, but is inferior
to an older version 0.5-micron PTFE laminate (which had a lower permeability than the grade presently
manufactured). Note that these IBR data were collected in discrete intervals with a HIAC/ROYCO 8000A
automatic particle counter and averaged, while the Oberlin data were measured with a Particle Measuring System
(PMS) instrument over the whole cycle (see Figure 3: Results of lab-scale ACFTD testing conducted by Inter
Basic Resources, Inc., Grass Lake, MI, USA).
Filtration Capacity (or Life)
The third property of filtration media that most end-users need to evaluate is filtration capacity (or life). In
ACFTD challenge tests conducted on both the Pall 47-mm disc filterability kit and the full-scale Oberlin 2.4 ft2
HA filter, meltblown media were demonstrated to have the longest life at 600 ppm. However, these media were
not shown to have a substantially longer life than microporous membranes -- and their filtrate quality is marginal,
at best. Tyvek® SoloFlo™ was shown to have approximately 80% of the life of the 0.45-micron microporous
membrane at 60 ppm ACFTD and approximately 85% at 600 ppm ACFTD, largely due to the lower permeability and porosity.
Although this is a moderate difference, the much lower cost of Tyvek® SoloFlo™ more than compensates for its
shorter life. Tyvek® SoloFlo™ also compared favorably to spunbonded and meltblown media in real-life
situations.

Filtration Costs

All too often when filtration media are purchased, only the initial cost is considered. But, for a true estimation of
"cost," several other factors should be considered. Generally speaking, the purchase costs of filtration media
range from microporous and PTFE membranes at the high end to meltblown media at the other end of the
spectrum. The purchase costs for flash-spun Tyvek® SoloFlo™ and other spunbonded media fall between these
two.
However, in typical wastewater applications (based on cents per gallon filtered), the actual costs of these products
become more apparent. The difference in purchase price vs. actual cost is most dramatic when comparing
microporous/PTFE membranes and meltblown media with Tyvek® SoloFlo™. Because Tyvek® SoloFlo™ can
be used as a single layer without support structures and can be reused in many wastewater applications -- unlike
most microporous/PTFE membranes and meltblown media -- its overall cost is half that (or less) of comparable
(1-micron) meltblowns and a fraction (5% or less) of the cost of microporous and PTFE membranes (see Table
1: Media Costs per Gallon Waste Filtered).
While Tyvek® SoloFlo™ exhibits only a slight deterioration in filtrate quality in comparison to microporous
membranes, it exhibits far better filtrate quality and superior strength than the low-cost meltblown media. And,
because of its much smoother surface, Tyvek® SoloFlo™ provides easy, dry cake release for more cost-effective
disposal.
Evaluating Filtration Media - A Comparison of Polymeric Membranes and Nonwovens
Submitted to Filtration & Separation Journal, Volume 35 No. 10, December 1998
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Evaluating Filtration Media - A Comparison of Polymeric Membranes and Nonwovens
Submitted to Filtration & Separation Journal, Volume 35 No. 10, December 1998
Page 5 of 6
Evaluating Filtration Media - A Comparison of Polymeric Membranes and Nonwovens
Submitted to Filtration & Separation Journal, Volume 35 No. 10, December 1998
Table I: Media Costs Per Gallon Waste Filtered
Actual Costs/Gallon Filtrate (cents/gal)*
Media Nominal
Rating (mm)
General Filtrate
Quality
60 ppm
ACFTD**
600 ppm
ACFTD**
2000 ppm
Lead-bearing
Waste Water
Microporous Membrane 0.45 Excellent 11 48 23
PTFE Membrane Laminate 0.5 Very Good 8.9 45 13
DuPont SoloFlo. 1 Very Good 0.5 1.3 0.3
DuPont style T-980 1 Very Good 0.8 2.1 0.5
Meltblown Polypropylene 1 Good 1.1 3.8 2.0
Meltblown Polypropylene 5 Poor 0.5 2.5 1.3
* Based on actual media costs, flux rates, and measured life cycles.
** AC Fine Test Dust (ACFTD) challenge testing.

Conclusion

To choose the appropriate filtration media for each application, purchase costs cannot be the sole determining
factor. Extensive research, testing and evaluation are required to make the proper selection. Based on the four
major criteria detailed in this article, Tyvek® SoloFlo™ from DuPont has been determined to be the most
economical for typical wastewater applications (based on cents/gallon filtered). Third-party challenge tests also
have confirmed that Tyvek® SoloFlo™ is quite efficient at low-micron ratings, approaching typical microporous
membranes in performance. In addition, Tyvek® SoloFlo™ compares favorably to PTFE membrane laminates at similar permeabilities and proves far superior to both spunbonded and meltblown media.
In recent years, innovations such as Tyvek® SoloFlo™ have expanded the role of nonwovens in filtration
applications. DuPont is continuing its research into alternative polymers for its flash-spinning process to provide
new alternatives to the filtration industry.