Pure Water Occasional, August, 2022
 
Greetings from Pure Water Products, the Pure Water Gazette, and the Pure Water Occasional.
 
 
 
In this Almost Labor Day Occasional you'll learn what filter carbon is made from and hear about things that affect the way water tastes. A sensible approach to protecting against lead in city water supplies,. Learn why ordinary is best when it comes to filter cartridge sizes. How to protect against water contamination caused by water treatment iself. Information about our simple undersink filters.   And, as always, there is much more.
 
Thank you for reading and sincere thanks from Pure Water Products for your continuing support.  We consider our greatest asset to be the many faithful customers who have kept us going over the years. We really appreciate your support!
 
Thanks for reading!

Please visit the Pure Water Gazette, where you will find hundreds of articles about water and water treatment.
 
 

What Kind of Carbon Is Best?

or, How Is Filter Carbon Like a Parking Lot?

by Emily McBroom and Gene Franks

The “carbon” (often called “charcoal”) that is used for water treatment is made from a variety of raw materials. Someone has said that filter carbon can be made from anything that contains carbon, even peanut butter. Most filter carbon is made from coal–bituminous, sub-bituminous, lignite–and from nut shells, especially coconut shells.
Some of the characteristics that are considered by filter makers when choosing raw materials for the carbon products are:
  1. Surface area – square meters of surface per gram of carbon. The surface area determines how much adsorption can take place and what types of contaminants the carbon can take onto its surface.
  2. Iodine Number – indicates the ability of the carbon to adsorb small, low molecular weight organic molecules, like volatile organic chemicals.
  3. Molasses Number – indicates the ability of the carbon to adsorb large, high molecular weight organic molecules, like colors.
  4. Bulk Density – indicates the density as pounds per square foot in a column. In general,  the higher the density, the more surface area available for adsorption.
Water Quality Association training materials provide such a good explanation of how these four parameters apply to carbon suitability that we can’t resist borrowing it.
The inside surface of the activated carbon particle can be viewed as a large parking lot for organic molecules. Further, one can view the large molecules as semitrucks, and the small organic molecules as compact cars. Using this viewpoint, it is easy to illustrate a number of things. First, if most of the pores in the activated carbon are micropores (small parking spaces), the semitrucks are going to have a difficult time moving inside the parking lot, and they will have difficulty finding a parking site which fits. But, the compact cars will have an easy time. (This corresponds to a high iodine number.) Second, it the pores are mostly macropores (large parking spaces), the semitrucks will be able to get around fine, but it will be an extremely inefficient way to park compact cars. (This corresponds to a high molasses number.) Third, if there are only a few roads connecting the various areas inside the parking lot, the cars will all pile up, and the roads will act as a bottleneck. Ultimately, a large number of small cars can be parked, but the parking lot will fill slowly. This is what happens if there is not a suitable mix of micropores (small spaces)  and macropores (big spaces).
So, activated carbons made from lignite coal tend to have large pores (macropores) and make good parking spaces for big trucks, like tannins.
Carbons made from coconut shells have very small  pores (micropores) and are especially good parking spaces for very small molecules like VOCs, which are the compact cars of the organic chemical world.
But over the years, the most widely used carbon material of all is bituminous coal, because bituminous carbon has big pores and little pores and a lot of mid-sized pores (mesopores)  that are just right for parking the great many average-sized family sedans, SUVs, and pickups. In other words, bituminous carbon is widely used because it works pretty well for just about anything. Bituminous coal based activated carbons are frequently a good first choice for general dechlorination and reducing the concentration of a large range of organics.
All carbons, by the way, work well for removing chlorine and even chloramine, although contact time with the carbon needs to be about twice as long for chloramine as for chlorine. (Specially processed carbon called “catalytic carbon,” which is available in coal- or coconut-based, is much better at chloramine removal than standard carbon.) All carbons work well for taste/odor improvement, and we find no scientific basis to support the common belief that coconut shell carbons make water taste better than other carbons.
There are other considerations, of course, that are left out of the parking lot method for choosing carbon. An important one for residential users is a test called Ball-Pan Hardness.  It puts a numerical value on the hardness of the carbon–how much banging around it will take before it breaks down.  In this test coconut shell carbon always comes out way ahead of bituminous. This is significant for tank-style residential filters because when carbon breaks down because of the rolling and tumbling of repeated backwashing it gets into service lines. Think of it as the coconut shell parking lot having tougher walls and posts to withstand the banging it gets from those wild compact car drivers.
Carbon made from peanut butter, by the way, fares poorly on the Ball-Pan Hardness test but has an excellent Molasses number and great Surface Area.
 
 

The Taste of Water: You like what you're used to

Switching Either to Chloramine or Chlorine Draws Taste Complaints

One of the headaches of water treatment is that whenever there is change, there is complaint. When cities switch from chlorine to chloramine disinfection, taste complaints are usually numerous and loud. The irony is that when there is a temporary switch back to chlorine, which regulatory agencies recommend periodically, there are equally strong complaints about the taste of chlorine in the water.
 
When chloramine is used as the primary disinfectant,  the ammonia and nitrogen in chloramine can cause a biofilm buildup in pipes. A periodic, short-term change back to free chlorine, a much stronger disinfectant than chloramine, clears out some of the buidup. Cities often refer to the temporary changes back to chlorine as “chlorine burns.”
 
Another item that affects taste is TDS, or Total Dissolved Solids, the mineral makeup of the water. That’s why when people become used to high TDS water (as in some bottled spring waters or some well water), they describe low TDS water, like reverse osmosis water or distilled water, as “tasteless.”  Reverse osmosis water drinkers, by contrast, are often shocked by the heavy mineral taste of tap water when they get a drink from a water fountain or restaurant.
 
With water, as with many things, people tend to like what they’re used to.  They may complain about the way things are, but when there’s a change,they complain twice as loudly.
 
 
 


 

Common Sense about Lead in Drinking Water

by Gene Franks

In ancient times, people drank from lead vessels because they didn’t know any better. There’s no longer any excuse.–Bloomberg News Editorial. 
Lead’s toxicity has been known for centuries, but lead remained a popular choice for water service lines installed up to the 1980s. It’s more flexible and durable than iron. About 6 million lead service lines are still in use today, connecting households to water mains. Prior to 1986, copper pipes inside a person’s home could also be joined with lead solder. —Olga Khazan in The Atlantic.
Some sobering information has surfaced because of the attention focused on the out-of-control lead contamination problems of Flint and Newark. We learn, for example, that the nation’s drinking water infrastructure has so many lead-emitting metal pipes that we can’t begin to count them, and, what is worse, we don’t even know where they are.
Here are some points to ponder:
  •  Lead in water supplies is not a new problem. It is mainly public awareness of the problem that is new.
  • The strategy for protecting the public from lead in water pipes, apart from vague, yet-to-be-funded proposals to replace the pipes, has been chemical treatment aimed at keeping pH high and adding sequestering chemicals. This seems to work most of the time, but the result isn’t predictable. Water treatment is complicated, and success can depend on variables like temperature, flow rate, and other chemicals present. Pipes and conditions in your home may be completely different from those where the supplier’s test was taken. Success of this strategy is also heavily dependent on the skill and dedication of the local technicians maintaining the system.
  • Testing required by federal regulators is sporadic. Tens of millions of gallons of water pass through the pipes between mandated tests. Finding no lead at a test site on Elm Street doesn’t mean there isn’t lead in a home on Maple Street. I used to say that the way testing is conducted is like checking one passenger at the airport and if he doesn’t have a bomb,  you assume that the next ten million passengers are also bomb free. Actually, with lead it’s worse that that: it’s more like testing one passenger and assuming that the next ten million passengers as well as the passengers at the airports of surrounding cities are bomb free. The odds that you are protected from lead by a test done five miles from your home six weeks ago are pretty bad.
  • The message we get from water suppliers seems to be: Be patient. We’ll get this fixed. You can count on us. Be sure to run your tap five to fifteen minutes before you drink the water. When things are really bad, they give free bottled water or provide a cheap pour-through water filter.
Conclusions
To protect yourself from lead, you could drink nothing but bottled water.  That isn’t a bad solution.  Or, you could  a) write letters to city officials demanding action, b) wait for all the lead water pipes to be replaced, c)  keep drinking tap water and hope for the best,  or, d) get yourself a good water filter. If you choose a through c, good luck.  If you choose d, I have some advice.
First, lead is a drinking water issue.  While whole house lead solutions are available, it is usually more practical to treat drinking water only. For lead-free drinking water, you have some good choices: a steam distiller, reverse osmosis, or a substantial carbon filter with lead removal resin added. Of the three, reverse osmosis is the most practical. Reverse osmosis removes lead by its nature, without the need for special cartridges. Reverse osmosis, of course, has the advantage of treating not only lead but virtually all contaminants that can be found in city water.
Lead reduction cartridge filters vary in quality, but any reasonably-sized undersink or countertop filter from a trusted filter maker will provide excellent, lead-free water. I underline “reasonably sized.” The pitcher filters provided free by cities don’t really qualify as water filters. They are novelty items made for pick up sales in discount stores. The early tests done on the city-provided filters in Newark that lead to a blanket “filters don’t work” warning were done with city-provided pitcher filters with only enough lead capacity for 30 gallons of water. They have a warning light for cartridge replacement that is there to inspire confidence. You really don’t need a warning light: you need more resin. A full-sized drinking water cartridge with lead removal rating of 2500 gallons from a reputable filter maker actually costs considerably less to operate than the tiny novelty systems.
 
 

The Advantages of Being Ordinary: Why Standard Sized Water Filters Are Best

 
Things get to be standard for a reason. — Latvian Proverb.
 
If you own one of the many popular drinking water systems that use uniquely sized replacement filters–Aquasana, Brita, and Pur, for example–the total number of replacement cartridges you have to choose from are one. 

That’s because the manufacturer has made the filter so that it will accept only one cartridge size–the size that the manufacturer alone makes. This practice is known in the industry as proprietary sizing. The purpose is to assure the maker that you can buy only his cartridges. It also relieves the maker of the need to provide variety. One-size-only normally also means one-style-only. Whether your water is disinfected  with chloramines, chlorine, or nothing at all, you get the same filter cartridge. If your water has lead or no lead, fluoride or no fluoride, it’s the same cartridge.
If, on the other hand, you own a drinking water system that uses a standard 9.75″ X 2.5″ filter cartridge, you can choose from literally dozens of different cartridge styles, and you can even buy a cartridge from a manufacturer other than the one who made the filtration system. This size, which we call Size 1 for convenience, is the most commonly made filter size. Almost anyone who makes water filters makes some cartridges in this size.
 
Below are some examples of standard-sized cartridges that will fit all standard-sized filtration units, countertop filters, undersink filters, reverse osmosis units, add-on filters, and even garden hose filters.
 
For an idea of the cartridge choices you get when you stick with a standard size, take a look at the cartridge offerings in 9.75  X 2.5 on this site.
 
Standard cartridges come in two general styles–radial and axial.  These can be interchanged.  In other words, if you purchase a water filter with a standard sized axial cartridge, you can replace it with a radial cartridge. The pictures below will explain.
 
 
The ChlorPlus 10 cartridge made by Pentek fits any standard housing. An excellent all-around carbon block, it is designed to be especially good at chloramine reduction. It fits countertop filters, undersink filters, and reverse osmosis units.or even out standard-sized garden hose filters.
 
The standard filter  shown above is a  “radial style” cartridge.  This means that water to be filtered passes through the outside wall of the filter cartridge and works its way into the core. The cartridge, therefore, has a very large filtering surface.
 
 

Above is an “axial” style media cartridge. It contains calcite, a sacrificial medium that raises pH and adds minerals to low pH water, plus coconut shell carbon for taste/odor and chemical treatment. Its most common application is as a reverse osmosis postfilter.

 
There are also many “axial style” cartridges that fit in standard housings as well. These interchange with radial filters and no modification of the housing is needed. Axials work differently. Rather than flowing through the side of the cartridge to the center, with axials water enters one end of the cartridge and flows the entire length of the cartridge to exit the other end. Cartridges of this type are often called “media” cartridges, since they use granular filter media. Most specialty cartridges (fluoride, iron, nitrates, arsenic, etc.) fall in this category. Granular carbon “taste/odor” cartridges as well are almost always axials.
 
The filters shown above are all standard drinking water size. Standard sizes also exist for larger units for higher flow or “whole house” applications..  Here are the common ones:
 
Size 2:  2.5″ x 20″
Size 3: 4.5″ X 9.75″
Size 4: 4.5″ X 20″
 
Cartridge diameter may vary a bit.
 
For a group picture of many cartridge sizes, both standard and proprietary, go here.
 
 

 
 
 
 

Chemical Contamintion Caused by the Water Treatment Process Itself:

Flaw Found In Water Treatment Methods

 Gazette Introductory Note: It took us several decades after public water suppliers started using chlorine as a disinfectant to figure out that the disinfection process was creating a seemingly countless group of pretty nasty chemicals that we refer to collectively as “disinfection byproducts” and regulate as THMs. It should not surprise us, then, than when we apply hydrogen peroxide and UV light to eradicate water contaminants we create “presumably less harmful chemicals” that the article below refers to as “transformation products.” Nature is about change. We know that when we “remove” something from water we are often just changing it to something “presumably less harmful.”  Chlorine doesn’t go away: it becomes chloride. So who knows what phenols from personal care products might morph into when exposed to oxidation?
Public water quality has received a lot of attention in recently years as some disturbing discoveries have been made regarding lead levels in cities across the country. Now, a new study from the Johns Hopkins University pinpoints other chemicals in water that are worth paying attention to — and in fact, some of them may be created, ironically, during the water treatment process itself.
To rid water of compounds that are known to be toxic, water treatment plants now often use methods to oxidize them, turning them into other, presumably less harmful chemicals called “transformation products.” Though earlier studies have looked at the byproducts of water treatment processes like chlorination, not so much is known about the products formed during some of the newer processes, like oxidation with hydrogen peroxide and UV light, which are especially relevant in water reuse.
“Typically, we consider these transformation products to be less toxic, but our study shows that this might not always be the case,” says lead author Carsten Prasse assistant professor in the Department of Environmental Health and Engineering at the Johns Hopkins Whiting School of Engineering and the university’s Bloomberg School of Public Health. “Our results highlight that this is only half of the story and that transformation products might play a very important part when we think about the quality of the treated water.”
Prasse, along with colleagues from the University of California, Berkeley, chose to look at phenols, a class of organic chemicals that are among the most common in the water supply, as they’re present in everything from dyes to personal care products to pharmaceuticals to pesticides as well as in chemicals that are naturally occurring in water.
To determine what compounds the phenols transform into during treatment, the team, whose results are published in Proceedings of the National Academy of Sciences, first oxidized phenols using peroxide radicals, a process often used by water treatment plants. Next, they borrowed a clever method from biomedicine: They added amino acids and proteins to the mix. Depending on what chemical reactions took place, Prasse and his team could do some backwards calculation to determine what compounds the phenols must have turned into in the earlier step.
They discovered that the phenols converted into products including 2-butene-1,4-dial, a compound that is known to have negative effects, including DNA damage, on human cells. Interestingly, furan, a toxic compound in cigarette smoke and car exhaust, is also converted into 2-butene-1,4-dial in the body, and it may be this conversion that’s responsible for its toxicity.
To test the specific effects of 2-butene-1,4-dial on biological processes more fully, the team exposed the compound to mouse liver proteins. They found that it affected 37 different protein targets, which are involved in a range of biological processes, from energy metabolism to protein and steroid synthesis.
One enzyme that 2-butene-1,4-dial was shown to bind is critical in apoptosis, or “cell suicide.” Inhibiting this compound in a living organism might lead to unchecked cell proliferation, or cancer growth. And other compounds that 2-butene-1,4-dial interferes with play key roles in metabolism. “There are a lot of potential health outcomes, like obesity and diabetes,” says Prasse. “There’s a known connection between pesticide exposure and obesity, and studies like ours may help to explain why this is.”
The results are exciting since this is the first time these methods have been applied to water treatment, Prasse says. In time, they may be expanded to screen for other types of compounds beyond phenols.
Water purification is extraordinarily challenging, since contaminants come from so many different sources — bacteria, plants, agriculture, wastewater — and it’s not always clear what’s being generated in the process. “We’re very good at developing methods to remove chemicals” says Prasse. “Once the chemical is gone, the job — it would seem — is done, but in fact we don’t always know what removal of the chemical means: does it turn into something else? Is that transformation product harmful?”
Prasse and his team point out that by the year 2050, it’s been estimated two-thirds of the global population will live in areas that rely on drinking water that contains the runoff from farms and wastewater from cities and factories. So safe and effective purification methods will be even more critical in the coming years.
“The next steps are to investigate how this method can be applied to more complex samples and study other contaminants that are likely to result in the formation of similar reactive transformation products,” says Prasse. “Here we looked at phenols. But we use household products that contain some 80,000 different chemicals, and many of these end up in wastewater. We need to be able to screen for multiple chemicals at once. That’s the larger goal.”
Coauthors on the study were Breanna Ford and Daniel K. Nomura of the Department of Nutritional Sciences and Toxicology at the University of California, Berkeley. The senior author was David L. Sedlak of the Department of Civil and Environmental Engineering at the University of California, Berkeley.
 
This research was supported by the National Institute for Environmental Health Sciences Superfund Research Program (Grant P42 ES004705) at the University of California, Berkeley.
SOURCE: Johns Hopkins University
 
 
 
 
 
 
 
 
 
 

Simple Undersink Filters
If  you want to install a high quality undersink drinking water filter but are unable to drill a hole in the sink or countertop for the ledge faucet, we have convenient, easy-to-install single,double and triple filters. They fit under the sink and filter all of the water that comes from your regular cold-water faucet. They cost less than our standard undersink filters because the separate faucet and inlet valve are not needed. They are very easy to install. No holes to drill, no faucet or inlet valve to install.
 
 
 
 
Places to visit for additional information:

 
 
 
 
 
 
 
Thanks for reading. The next Occasional will be out eventually--when you least expect it.
Pure Water Products, LLC, 523A N. Elm St., Denton, TX, www.purewaterproducts.com. Call us at 888 382 3814.
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