Pure Water Occasional, August 18, 2021 |
This summery Occasional talks about "softening" water, what it means and ways to go about it. We weigh the pros and cons of the three types of sediment filters and explain how ultraviolet light is used in water treatment. We're reprinting an earlier article about the sad state of the nation's water pipes in hope that you'll recognize the urgent need for public expenditures on infrastructure.
We sincerely appreciate you.
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News about Us
Pure Water Products is experiencing the same persistent problem as the rest of the water treatment industry: parts shortages. Some things are hard to get now. Mineral tanks for large filters and softeners and selected filter cartridges are at the top of the list. We're trying very hard to keep things in stock and to provide substitute parts when we can't. We appreciate your patience.
Pandemic news: We went from masked to unmasked and are now back to masked. Our employees who have customer contact at our Denton location are masked and 100% vaccinated. Our store is as safe for customers and employees as we can make it. And, in spite of what a friend of someone's cousin read on Facebook, the virus is not spread by Chinese glue used on UPS labels, so you can order from us with confidence.
Prices: Our prices are way overdue for upward revision. Everything--wholesale product prices, shipping charges, the cost of packaging materials--is going up rapidly. Product cost increases are significant--not the usual one or two percent per year, but 10% or 12%. Look for significant price increases for products and parts, from us and from everyone else.
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FAQs
This section always includes actual questions received since the previous Occasional and our actual answer.
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Question:
I recently bought your garden hose “softener” to wash my cars with (works GREAT btw). With the unit came the “softener test strips”.
I have been using a Watts device I bought from you for the whole house for about 6-8 months ago. It seems to have decreased scale buildup, but now for the question…
The test strips indicate 450, very hard, on my house water out of any faucet. How do I know when the medium is “used up” or needs to be recharged? I can’t imagine it needs to after 6+ months. Or is the testing methodology not appropriate for this type of system? Thank you for your time.
Answer:
First, glad both products are working well.
The hardness test strips test for the a presence of calcium and magnesium, the minerals that cause water hardness.
The softener that you're using for car washing contains actual water softening resin. It removes the calcium and magnesium by means of ion exchange. The test shows a reduction in hardness because the calcium and magnesium are reduced.
The Watts unit, on the other hand, isn't really a softener. It's a TAC system that doesn't actually remove anything. It conditions the hardness minerals so that they don't set up as hard scale, but the minerals are still there and the hardness test finds them. Hardness tests don't work with TAC units.
There is currently no test that tells you when the TAC medium is spent and needs to be replaced. For residential TAC units, Watts recommends media replacement every three years. TAC media cannot be regenerated.
The softener resin, of course, lasts much longer because it can be regenerated by passing a strong brine solution through it.
Question:
Can AerMax units be used with constant pressure well pumps?
Yes, definitely, but there are a couple of things you need to know. First, the pump has to be controlled with a timer. There are no options.
Second, since constant pressure systems usually maintain a higher pressure than conventional bladder tank systems, it's best to use the upgrade CAP AerMax pump rather than the standard model. The CAP also needs an upgrade installation kit.
At current pricing, the pump/installation kit upgrade adds about $220 to the price of the standard 110 V. AerMax unit. The other parts are all the same.
The standard air pump can be used with constant pressure wells, but the upgrade pump works better and has shorter service runs.
Programming the unit, with either the standard pump or the CAP, for most residential applications means running the pump enough to do a complete turnover of the unit's air pocket at least 3 times per week. This means running the standard pump 3 times per week at about 18 to 20 minutes per session or running the CAP unit about 2 minutes per session. (The CAP has about 10 times the air output of the standard pump.)
The high output CAP air pump.
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TAC or Water Softener: Pros and Cons
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With the growing popularity of alternatives to conventional water softeners, most notably Template Assisted Crystallization (TAC) systems, residential customers are finding it more difficult to choose a home treatment system for hardness.
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Siliphos is a milk thistle extract. It is made of 100% food grade materials.
Siliphos prevents scale formation and stops corrosion of pipes. After months of use, it can actually slowly remove some of the existing scale from pipes and appliances.
Siliphos acts as a sequestering agent, coating the inside of pipes and making a thin protective layer on metal surfaces to prevent scaling, corrosion and brown or red water.
Siliphos does not alter the taste of the water. It dissolves slowly into the water and acts by preventing the adhesion of minerals to metallic surfaces.
It can be added as an inexpensive whole house or point of use treatment. Siliphos spheres can be inserted into the center core of carbon block or sediment filters or dispensed through a separate filter housing installed in the water line. The larger system with separate housing lasts longer and supports higher flow rates.
Unlike conventional water softeners, Siliphos is inexpensive, easy to install, does not use salt or electricity, and does not add sodium to water. Siliphos costs considerably less than TAC softener alternatives.
Basic Stand-Alone Siliphos Units from Pure Water Products
| Unit Description |
Home Size |
Cartridge Size |
| Compact Unit with Clear Housing. Installs on 3/4″ pipe. Cartridge holds 100 siliphos spheres. |
One or two people. |
9.75″ X 2.5″ |
| Standard Unit with Blue Housing, for 3/4″ or 1″ Pipe. Cartridge holds 200 siliphos spheres. |
Two to Six People |
9.75″ X 4.5″ |
| Large Unit with Blue Housing for 1″ or 1.5″ Pipe. Cartridge holds 250 siliphos spheres. |
Six people or more |
20″ X 4.5″ |
All Units have replaceable cartridges.
Please call 888 382 3814 for pricing of Siliphos units or to order.
Mid-Sized Siliphos Unit, uses 4.5″ X 9.75″ replaceable (or refillable) filter cartridge with 200 Siliphos spheres.
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Water filter cartridges whose function is to trap suspended particles come in three distinct styles. Mr. Robert LeConche, President of Shelco, one of the largest makers of sediment filtration products, describes them like this:
Wound Filters. Wound filters are versatile all-purpose filters that exhibit rather high dirt-holding capacities. They are relatively low cost, depending on the materials of construction, and work well in most applications. This style of filtration offers great compatibilities because of a wide range of raw materials available for production. Its distinct diamond patterns create fluid channeling from the outer diameter to its center core making it a true depth filter. One caution is that low-quality wound filters used under high differential pressures have a tendency to “unload” or release sediment that was previously filtered out of the solutions.
Melt blown or Spun. Melt-blown or poly spun filters are almost always made of FDA-grade materials for use in potable water and food and beverage applications. There are two levels of product efficiencies, Nominal and Absolute rated. Nominally rated cartridges should offer efficiencies ranging from 70% to 80%. Absolute or High Efficiency Melt Blown Cartridges will offer efficiencies in the range of 90% to 99%. Melt-blown filters are usually a lower cost option to wounds or pleated cartridges (although they may require more frequent cartridge changes).
Pleated. Pleated filters offer higher flow rates with lower clean differential pressures and extended filter life than most cartridge filters. They are almost always made of FDA grade materials for use in potable water and food and beverage applications. Pleated filters can be used alone or as final stage filtration in multi-stage filter systems. Although pleated filters typically are more expensive than other filters, they have a longer filter life and some can be clean and reused (when appropriate). Pleated cartridges also offer nominally rated and bsolute rated alternatives.
As to which is “best,” our answer is usually that it depends on the individual case. Some customers prefer one, others swear by another. Whichever works best in your situation is the best.
Wound string and melt-blown cartridges are called “depth” cartridges because they can trap and hold particles beneath the surface, while pleated filters trap and hold sediment on the surface only. However, pleated filters have much more surface area than the other styles because of the unique accordion shape. Although pleated cartridges usually cost more, they can be washed and reused in most cases. The rule of thumb is that pleated cartridges of 5-microns or more can be reused; tighter than 5 microns, reuse usually is impossible. Because of their great surface area, pleated cartridges can often support a higher service flow rate as well.
A well-used wound string filter. Note the diamond patterns mentioned by Mr. LeConche.
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Ultraviolet 101
by Gene Franks
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Although ultraviolet light has several water treatment applications, such as reducing chlorine and chloramine, its main use by far is for microbe control.
Getting rid of microbial water contaminants can be done with chemicals, like chlorine or chloramines, by very tight filtration, as with ceramic filters, or by disabling the microbes with ultraviolet light.
Ultraviolet, UV, is not new. As early as 1877, the germicidal properties of sunlight were known.
Landmark events in the development of modern UV treatment include the use of mercury lamps as an artificial germicidal light source (1901), the development of quartz as a UV transmitting medium (1906), and finally the development of the first genuine drinking water application of ultraviolet as a disinfectant in France in 1910.
The technology is, therefore, a century old, and it is used world wide. Nevertheless, it is still unknown to many US state and local regulating agencies, who continue to accept chlorination as the only acceptable way to purify water.
UV treatment works not by “killing” bacteria, protozoa, and viruses, but by altering their DNA so that they cannot reproduce or infect. If chlorination is like chemical warfare directed at microbes, UV is more like a spaying and neutering program.
UV Light
UV light in the 200 to 300 nanometer (nm) range is the most effective at treating bacteria and viruses. (Visible light falls in the 400-700 nm area.) For most practical UV applications in water treatment today, the light is generated by a mercury vapor lamp, or in a gas mixture that contains mercury. Mercury is the gas of choice because the light it puts out is in the germicidal wavelength range.
Lamp output depends on concentration of mercury within the lamp, and the concentration depends on pressure. Low pressure lamps (called LP), the most common, produce UV light primarily at 253.7 nm, an ideal treatment wavelength. Some newer lamps are called “low pressure/high output” (LPHO) and some applications now use mixed vapor lamps called “amalgam” lamps. These require more electrical input and generate more UV output. LPHO lamps are roughly twice as powerful as LP, and amalgams may be about four times as powerful as LP.
The Delivery System
The standard way to treat unsafe water with UV is to send it though an elongated chamber where it is exposed to the intense light from the mercury lamp. UV bulbs are long and narrow to allow prolonged exposure as the water passes the length of the lamp.
The lamp itself is inside a “quartz sleeve,” which protects it from contact with the water, and on the other side of the sleeve there is normally a metal reflective chamber. The water enters one end of the chamber, flows past the lamp to exit at the other end, and is in the process exposed for some time and at close proximity to the UV dosage put out by the lamp.
UV Lamp, on left, and a quartz sleeve (for a smaller unit).
UV dosage is typically measured in units called “Joules,” and it is most frequently expressed in terms of “mega Joules per square centimeter,” or mJ/cm². (Microwatts per second per square centimeter, expressed as µWs/cm2, and mJ/cm2 represent the same dosage and the two systems are used interchangeably.) The higher the number, the higher the dosage.
UV Dosage
The UV dosage received by the water increases as the flow rate of the water decreases, so a UV unit that puts out a dosage of 16 mJ/cm² while treating water at a flow rate of eleven gallons per minute (gpm) will be rated as 40 mJ/cm² if the flow rate is decreased to 4.5 gpm.
Put another way, a UV system rated by its manufacturer to treat water at 40 mJ/cm² at 4.5 gpm will be delivering a dosage of 16 mJ/cm² even if the user exceeds the recommended limit and runs the water at eleven gpm.
The tendency now in UV dosage is to follow the “more is better” view we’ve all been indoctrinated in. If ten nuclear bombs will destroy the world, to be safe we need ten thousand. The most common concerns, E. coli, Giardia, and Cryptosporidium, are effectively eliminated at less than seven mJ/cm². The minimum dosage now recommended by NSF, however, is 40 mJ/cm².
Factors That Affect UV Effectiveness
First, there is the age of the lamp. UV lamps lose strength with time, and almost all manufacturers assume a once-a-year replacement when they design their units. It is a mistake to believe that if the lamp is still burning all is well. UV lamps should be replaced once a year, and when replaced they should still be burning strong.
Then there is flow rate. The unit should be sized to provide adequate protection at the highest possible flow rates, but practicality should tell you that in most residential situations, most water is used at a couple of gallons per minute and a great deal of the time—most of the time, in fact—no water at all is being used.
Also a factor is general absorption of the UV light for unintended purposes. UV makers usually require that water have less than seven grains per gallon of hardness, less that 0.3 ppm iron, less than 0.05 ppm manganese, and that it be generally clear and free of particulate and tannins. All of these can create situations where the light is absorbed and, therefore, its anti-microbial activity is diminished. Hardness, for example, can form scale on the outside of the quartz sleeve which blocks the passage of light and greatly diminishes dosage.
A related factor is called shadowing. It is primarily caused by particles in the water which can allow microbes to “hide” from the light and not receive adequate UV dosage. The commonly accepted practice in UV treatment is to put a sediment filter of 5 microns or less in front of the treatment chamber to screen out any particles that could allow shadowing. Even if the water looks perfectly clear to the eye, putting a five-micron filter in front of the UV unit is a good idea.
UV as a Germicidal Treatment. Pros and Cons
The good thing about UV is that in addition to being a very effective treatment for microbes, it is relatively simple and inexpensive to buy and to maintain. It adds no chemicals to the water and leaves no “by-products.” It is very safe, if you follow a couple of simple rules (like don’t stare at a burning UV lamp because it can damage your eyes and remember that treatment chambers can be hot to the touch).
Compared to ozone, chlorine, or even hydrogen peroxide, UV is a very safe home
treatment. Also compared with other treatments, UV requires little maintenance.
The main disadvantage of UV as germicidal treatment is that it has no residual effect. Bacteria are treated when they pass the lamp, but contamination that occurs downstream of the lamp is not treated. Chlorine, by contrast, stays in the water from the point of treatment to the final point of use and prevents reinfection. The need for a constant supply of electricity can be seen as an additional disadvantage.
If the power goes out, you should not use the water.
Above, a very basic UV system. The lamps provide strong UV dosage (30 mJ/cm2). Easy to install.
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America’s Dirty Little Secret
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Water Online writer Sara Jerome, in her article “Small Town, Big Water Problems,” says that in the small Louisiana community of Enterprise, the tap water is so bad that “one woman drives 20 miles each way to do her laundry in another town.” The water situation in Enterprise illustrates a festering problem in the United States: Funding for infrastructure repairs and upgrades in small communities is hard to come by.
Jerome continues:
“Years of water system neglect means that the 250-or-so residents there are left with pipes that leak more than 70 percent of their water into the ground — all because they can’t afford to fix them,” CNN reported, citing John Tiser, resident and water board president.
But Enterprise is hardly alone.
“The EPA estimates $132.3B is needed to repair small water systems in America over the next 20 years. But, in 2017, only $805.7M was allocated to these systems — about 12 percent of the amount needed,” CNN reported.
Virginia Tech Engineering Professor and water expert Marc Edwards refers to it as America’s “dirty little secret.” He explains that oftentimes towns like Enterprise are stuck with aging infrastructure that they can’t fix, leaving few options for them to deal with complaints about dirty or contaminated water. Edwards received a nearly $2M grant to uncover water issues in towns like this.
When Edwards and a scientific team tested Enterprise’s water in 2017, they found bacteria, lead and other contaminants that exceeded EPA limits.
“The whole idea is, at the end of this, to come up with a model to predict which cities are likely to have problems,” Edwards said. “Which cities are most likely to have lead pipes, and not be following the rules, and then work with communities there to figure out if they do have a problem, then build algorithms for individual homeowners to protect themselves, from sampling to filters.”
It is important to point out that while “over 92 percent of U.S. residents who receive water from community water systems are supplied by water that meets health-based standards at all times,” the U.S. EPA estimates that over $743B is needed for water infrastructure improvements.
To illustrate the extent of the water problems that plague small U. S. systems, here are more Water Online articles:
18 Million People Served By Systems With Lead Violations. Public officials have often failed to step in when water systems violate the federal Lead and Copper Rule, according to a report released this week by the advocacy group Natural Resources Defense Council (NRDC) on the “extraordinary geographic scope” of lead contamination.
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Places to visit for additional information:
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Thanks for reading and be sure to check out the next Occasional!
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