Pure Water Occasional, March, 2024
 
 
In this Easter Occasional you'll read about chlorine burns, manganese and how to get rid of it, the tragic bridge disaster in Baltimore, the water crisis in Mexico City, flooding from glacial lakes, TCE, saving water by raising water pressure, microplastics from clothing , the interaction of water and trees, the history of water treatment with UV,  and, as always, much, much more.

Thank you for reading, and sincere thanks from Pure Water Products for your continuing support.  
 
Thanks for reading!

Please visit the Pure Water Gazette, where you will find hundreds of articles about water and water treatment, and the Pure Water Products main website, where there is much information about water treatment and specific information about the products we offer. On both of these information-rich sites, pop-up ads and other distractions are not allowed.
 
 

 

What Are Chlorine Burns?

by Pure Water Annie

Gazette technical wizard Pure Water Annie addresses the perplexing questions about water treatment.

Once a year, usually in spring,  water suppliers that normally disinfect their product with chloramine, a mixture of chlorine and ammonia, perform a cleaning procedure known as a “chlorine burn.”  The purpose is simply to clean out the pipes, ridding the distribution system of film and debris that has built up.
The clean-out is accomplished by simply switching disinfectants from chloramine to straight chlorine for a time, and usually upping the dosage a bit to speed things along. Compared with chlorine, chloramine is a rather weak disinfectant.  Its weak performance allows sludge and scum, bacterial film, to build up in pipe walls and crevices.  The yearly purge, or “burn,” with straight chlorine cleans things out.
 
 
Chloramine has been substituted for chlorine as the regular disinfectant in an increasing number of city water systems. The switch from chlorine to chloramine has been going on over a number of years as suppliers seek ways to stay in compliance with EPA standards for DBPs,  disinfection by-products, that are produced as a consequence of chlorination. Some DBPs are known carcinogens, and EPA requires suppliers to monitor them.  Chloramine, a weaker disinfectant, does not produce DBPs.
 
 
Are chlorine burns a good idea?  Good or bad, they are necessary, since without a periodic cleanout, buildup in pipes would create significant problems for the water system.  The practice does call into question, however, the wisdom of using chloramine rather than chlorine in the first place, since, as many argue, the burn and subsequent purging of pipes creates elevated levels of disinfection by-products in the system and higher than normal chlorine discharge into lakes and streams. In other words, for a short time we get concentrated doses of disinfectants and byproducts, which may be worse than what we would have with chlorine as the regular disinfectant.
 
 
The moral: With a good carbon filtration system in your home, you won’t even know when the burn takes place.  The elevated chlorine levels, murky water, and dislodged sediment that your neighbors are complaining about, you won’t even notice. If your city uses chloramine, you should use equipment that is designed for chloramine treatment. Any filter that removes chloramine also removes the chlorine used during the annual burn.
 
 

Manganese

 by Gene Franks

Note: This article first appeared in The Pure Water Gazette in 2013. The website version has more illustrations if you would care to read it online.
 
Manganese is a naturally occurring mineral that is present in soils, rocks, and sediment. It is a beneficial mineral found abundantly in many common grains and vegetables.  It is essential to human nutrition, but in water it is generally regarded as unhealthy for humans in concentrations of as little as 0.5 parts per million.
In deep water wells, manganese can be found in concentrations as high as 2 to 3 parts per million, although amounts are usually smaller. As little as 0.05 parts per million (ppm) can cause black and brown staining. Manganese often exists with iron, and the two together often make chocolate-colored brown stains.
In general, manganese is difficult to remove from water because removal depends on its state of oxidation, the pH of the water, the presence of other minerals, and the TDS (total dissolved solids) of the water being treated. Another complication is that manganese often appears along with iron and hydrogen sulfide.
Evidence of manganese is often first seen in dishwashers because detergents raise the pH of the water high enough (>8) to allow manganese to precipitate (come out of solution and take on a solid, visible form). Another place to look for manganese is in toilet tanks, where it often appears as a floating film on the surface of the water. Shining a flashlight on the surface of the water makes the manganese film more obvious.

Forms of Manganese

Like iron, manganese in water takes on two forms.
The first and the most common is technically manganous manganese. In this state the manganese is completely dissolved in the same way that sugar or salt are dissolved in water. To be removed with a filter, manganous manganese must first be “precipitated.” It can, however, be removed by a water softener most readily in this form.
After precipitation, manganous manganese becomes a solid and no longer remains in solution. It can turn water black. This form is called manganic manganese. Precipitated manganese is easily removed by a filter, but it is not removed well by a water softener.
It is important to understand that a water softener is an ion exchanger, not a filter. It deals with un-precipitated ions. Filters can’t remove manganese or iron in their un-precipitated state.  Softeners can serve as filters for precipitated manganese,  but they are poor filters at best.
 

Removing Manganese from Water

The water treatment for manganese is similar to that for iron although there are some important differences, mainly involving pH. Removing manganese with a filter requires a higher pH than iron. Removing manganese with a filter is usually easier if iron is present.

Removing Manganese with a Water Softener

If conditions are right, a water softener is the best tool for removing manganese. The softener can handle significant quantities of manganese, but it only works well if all the manganese is un-precipitated and remains un-precipitated. Precipitated manganese is not only poorly removed by the softener, but it is especially harmful to the softener resin.
Here are the conditions that most affect a softener’s performance as a treatment for manganese:
TDS: Softeners remove manganese best if the total dissolved solids (TDS) of the water is low. When TDS is high, other minerals in the water compete with the manganese for space on the resin and can even displace manganese which has attached to the resin. Water with <500 ppm TDS works best for manganese removal by a water softener.
Dissolved Oxygen: Water with a low dissolved oxygen level lends itself best to manganese reduction by ion exchange. This is true simply because high oxygen levels promote precipitation of manganese to a physical form that is hard for the softener to handle. The opposite, as we shall see, is true if manganese is being treated with a filter. [This applies as well to the presence of oxidizers other than oxygen. To remove manganese with a softener, the water should not be chlorinated or treated with other oxidizers like ozone, hydrogen peroxide, or potassium permanganate.]
 pH: There are mixed recommendations from experts on this topic, but logically pH needs to be lower than 8 if a softener is to remove manganese as an ion. The pH must be low to prevent precipitation which occurs at higher pH levels. This is also contrary to what is needed for manganese removal with a filter.
As is also true with iron, when treating manganese with a water softener it is best to use a high salt dosage and keep service run short to avoid mineral build-up on the resin. Frequent regeneration is important.

Removing Manganese with a Filter

To remove manganese from water with a filter, a high pH reading and a sufficient oxygen content are necessary to insure precipitation. Although different filter media have different requirements, in most cases a pH greater than 8 is needed for effective manganese removal. Very active media such as Filox will work at a lower pH. Standard media like Birm may need a pH as high as 8.5 to effectively remove manganese.  In most cases, an oxidizer like chlorine, air, ozone, or potassium permanganate is used as a pretreatment to filtration. Amendment of pH is also often needed.
Removal of manganese with a filter can vary from very simple, with any good granular medium, to a much more complicated two or three step process which requires adding an oxidizer and a pH amendment step.

 Simple Filter 

Manganic manganese can be easily removed by a simple filter. If the amount is very small, a cartridge-style sediment filter will serve. If a significant amount of manganese is involved, a backwashing filter containing multi-media (sand, garnet, anthracite, for example), Filter Ag, Zeolite, Micro Z, or any good sediment reduction medium can be used.

Catalytic Media

In cases where un-precipitated manganese is present in a relatively low concentration and the oxygen content and the pH of the water are reasonably high, manganese can be handily removed with filter media that serve as catalysts to change the manganese to its precipitated form. Media such as Birm, Filox, and Katalox Light will cause the manganese to convert to its physical form,  then filter out the precipitated manganese in the same operation. Backwashing the filter then rinses away the trapped contaminant and restores the filter bed. Filters of this type are very effective if conditions are right, and they seem to work best if there is more iron in the water than manganese. Catalytic media filters can also be used after pretreatment with an oxidizer, as described below.

Pretreatment/Oxidation Filters 

Pretreatment usually means a free-standing oxidizer, but it can also include pH enhancement.

Aeration 

Pretreatment with air can be done in a number of ways. The oldest is with a “venturi” setup that is installed before the well’s pressure tank to draw air into the water line. The venturi is usually followed by a small vent tank that gives the air time to oxidize the manganese and to get rid of excess air. The water then goes to the filter, where the manganese is removed. A more aggressive and more effective system uses a larger treatment tank into which air is fed from a small air compressor. Air is compressed into the top third of the tank and oxidation occurs quickly as the water being treated falls through the pocket of compressed air. The filter follows the aeration tank. A variation on the compressed air system does the aeration in the filter tank itself, using, again, the top third of the tank and relying on an air draw feature supplied by the filter’s control valve rather than a compressor. All three aeration methods can be effective. 
 
Aeration, of course, assures that the dissolved oxygen required for manganese removal is present, but pH is still a concern. A calcite tank can be added before the filter, but with the high pH requirement of manganese, soda ash or caustic soda injection usually works better.
When the water is properly pretreated with air and a pH enhancer, any good filter medium will remove manganese. Best results are gained, however, by using a top grade iron medium like Filox.

Chlorination 

Chlorine is a strong oxidizer, but it requires more “residence time” than air.  Chlorination can be done via a pellet dropper (dry pellet chlorinator), which drops calcium hypochlorite pellets into the well itself, or with a feed pump which injects liquid chlorine under pressure into the water line. If the pump is used, a retention tank must be added to give chlorine time to do its work. At least 20 minutes residence time is usually recommended.
As with aeration, the chlorination step must be followed by an iron filter. The choice again is wide, but one of the standard filters that works well independently or following aeration, Birm, cannot be used with chlorine. Carbon works well if the amount of manganese is small, and catalytic carbon works better than standard carbon. Carbon has the advantage of removing the chlorine along with the manganese.
When chlorine is fed by a pump, a pH increaser like soda ash can be injected along with the chlorine.

Potassium Permanganate 

Potassium permanganate, a strong oxidizer, is used almost exclusively with filters using greensand as a medium. It is usually drawn into the filter during its regeneration stage.  Greensand filters are effective removers of manganese, iron, and odors, but they are generally more difficult to maintain and are, therefore, not a favorite with owners of residential wells.
Ozone and hydrogen peroxide are also powerful oxidizers of manganese, but since they are less frequently used in residential treatment, they aren’t being considered here.
More information about products that remove manganese:

History of Ultraviolet Water Treatment
 
 
 
Although UV has other applications in water treatment, such as chloramine reduction, by far the most common use is for germicidal disinfection. As the picture illustrates, the standard UV dosage for germicidal treatment is 254 nanometers.
Although it has taken a long time for the technology to become widely adopted, UV has been around for a long time. In 1877, the germicidal properties of sunlight were discovered and it was only a matter of time before people tried to apply this knowledge for practical use. In 1903, Niels Fensen received a Nobel Prize for his use of ultraviolet light to combat tuberculosis, and in 1910, the first drinking water disinfection system opened in Marseilles, France.
 
From that time, the technology changed very little until the 1930s, when the first tubular lamps were developed. The tubular lamp allowed for easier applications and different configurations for use. 

In the 1950s, the first truly significant research into UV disinfection began. By the 1960s, UV disinfection was becoming more widely used in commercial applications and was creeping into the residential market.
 
Today, ultraviolet disinfection is widely accepted as an effective treatment for the removal of microbiological contaminants from water. Although it was initially viewed as a treatment for un-chlorinated well water, the use of UV for city water residential applications is increasing rapidly. As the infrastructure that cities use to deliver water to customers deteriorates, point-of-entry UV is expected to become a standard feature in homes. 

Even highly chlorine-resistant microbes such as Giardia and Cryptosporidium can be effectively eliminated from water with UV. UV systems are becoming an increasingly popular alternative to chemical treatment for many applications. 

Reference: Viqua.  

Trying to drive on a flooded road is usually a bad idea.
 
According to the National Weather Service, more deaths result from drowning due to flooding than any other severe weather event. That’s because rushing water is a tricky thing. Is it an inch deep or a foot deep? Is there debris being deposited in the road that can damage the car or the tires? How powerful is the rushing water? There’s no way to know until it’s too late.
 
Six inches of water will reach the bottom of most passenger vehicles, causing the loss of steering and control; 1 foot of water will cause most vehicles to float; and 2 feet of rushing water can sweep away almost all noncommercial vehicles — including sports utility vehicles and pickup trucks.

Why We Send Postcard Reminders
 
If you have a product of ours that requires regular replacement parts, we send you a postcard reminder once a year. Reminders go to customers who need filter cartridges for whole house or drinking water filters or reverse osmosis units, washing machine or garden hose filters. Even shower filters.  UV customers also get cards to remind them to replace the ultraviolet lamp.
 
 
Cards are sent with the broad assumption that cartridges and lamps need to be replaced once a year. It’s an imperfect system, and once a year is as close as we can get. We realize that in some homes one person uses the shower filter while in others six do.   People often tell us things like the filter is in a summer home that is unoccupied much of the year, or that their daughter has gone away to college, so they don’t need replacements as often. That’s way too complicated for us. We are simple people and it’s a simple system.  Once a year. And it’s once a year from your last purchase: If we send a card in February and you purchase in April, you’ll get your next reminder in April. And if you don’t purchase, you don’t get another postcard.
 
And if you get a card and don’t buy anything, you won’t get another card until you buy something, so rest assured that buying a countertop water filter from us does not put you on a never-ending mailing list. We aren’t like the Vet who’ll keep sending cards until you take Bowser in for his rabies shot.
 
Postcards may be the most popular thing we do, judging from the many thank-you notes we get. Cards make re-ordering easy. They tell you what you need to know to order by phone or from our website.
 
Why don’t we send email reminders instead? Email is cheaper and easier. We’ve tried, and email isn’t even remotely as effective as a postcard.
 

 

 

Water Treatment Information
 
We've been collecting information about water and water treatment since the 1980s. We invite you to make use of it.
 
The Pure Water Gazette website has well over a thousand articles on water and related issues. Read to your heart's content in a popup-free environment.
 
Pure Water Products main website has lots of well organized information about most aspects of water treatment. Please visit and read at leisure without insulting BUY NOW! intrusions.
 
We've lost track of how many back issues of the Pure Water Occasional we have archived, but you can find links to many of them here. 
 
 
 
 
 

 
What Does TDS Mean to the Home Reverse Osmosis Owner?
 
Our Black and White RO units come with a hand-held Total Dissolved Solids meter. We include it as part of the unit. Here's why. 
 
 
 How do I know when to change my RO membrane?

Some sellers say every two years, other say every three.  Actually, the only really good way to know is to own a TDS tester, test the water from the unit once or twice a year, and change the membrane when the meter tells you it's time.  Membranes can last many, many years, and there is no reason ever to change a membrane that is performing well.

What does TDS mean, and what's a TDS meter?

TDS stands for "Total Dissolved Solids."  It is basically a measurement of all the "solids," or minerals, dissolved in the water.  The "dissolved solids"  consist mainly of calcium and magnesium (hardness minerals) and sodium, chloride, and sulfate.  A TDS tester for home use is a small electronic tester that measures these solids by passing a weak electrical current through the water and determining how well the water conducts electricity.  The higher the dissolved solids content, the more easily the water conducts electricity and the higher the number shown on the meter.
 
 
 
 
Does my RO unit remove the TDS from the water?

Yes, a healthy RO membrane will normally "reject" 90% or more of the dissolved solids and send them down the drain pipe.  RO units and steam  distillers lower dissolved solids. as do "deionizers." Filters don't removed dissolved minerals.  No matter how many sediment filters or carbon filters you run the water through, the TDS reading will remain the same.
 

Is TDS bad?  How high should it be?

Within the normal range of fresh water, TDS isn't a big health issue.  The EPA sets a limit of 500 parts per million Total Dissolved Solids as a drinking water standard, but many US cities violate that and their citizens do fine. Obviously, there is a point where water starts tasting bad.  This varies depending on which minerals are involved. Naturally soft water with a TDS of 500 that's mainly sodium, for example, can taste very good.  There is, of course, a limit: sea water is over 30,000 parts per million and is undrinkable. When water gets over 1000 ppm TDS you normally won't like the way it tastes.


My local tap water is 250 ppm Total Dissolved Solids.  If you're saying this isn't "bad for me," why bother to measure my RO unit's dissolved solids performance?  What does it matter whether the RO unit reduces the TDS or not?


TDS measurement is the standard way of evaluating overall performance of the RO unit.  The assumption is that if the unit is making a 90% reduction of calcium and sodium, it's also reducing arsenic and fluoride with equal effectiveness.  As it loses its ability to reduce TDS, it loses its ability to remove chromium. In other words, TDS readings are taken to determine how well the membrane is working.


What does "% rejection" mean?


Percent rejection is a calculation used to express  how well the RO unit is working.  It is determined as follows:

TDS of the feed water (determined by testing your tap water at the kitchen sink) minus the TDS of the permeate (the water that comes out of the RO unit's faucet) divided by the TDS of the feed water and multiplied by 100.

So, for example, if your tap water reads 280 and your RO product water reads 15, you determine the percent rejection of the RO unit by subtracting 15 from 280 to get 265, dividing 265 by 280 to get 0.946, then multiplying by 100 to get 94.6% rejection.  Your RO unit is running well.

You actually don't have to work through this whole formula to know if you're RO unit is running well.  If the RO water tests 1/10 or less of the tap water, it's doing fine.


At what TDS reading should you change the membrane?


That's a personal choice and there isn't a specific answer that fits all situations.  Consider, for example, that if your tap water TDS is only 65 and your RO unit is testing at 20, you still have some really good water and you might want to cut your membrane some slack and let it go on another year.

Are there factors that affect TDS readings that should be considered?  

First, never test your TDS immediately after changing your filters.  You'll get an artificially high reading because of impurities that your eye can't see being put out by the new post filter.  Also, keep in mind that cold water reads lower than warm and a stopped up pre-filter can rob the membrane of pressure and diminish its performance. And especially consider that if your RO unit has a remineralizing postfilter (as many do these days), the minerals added by the remineralizing filter can significantly increase the TDS reading. If this is the case,  you can simply assume that the remineralizing filter is adding a few points and ignore it, or you can get an exact TDS reading for the membrane by taking your sample for testing directly from the RO unit's storage tank.  
 

Water News —March, 2024

Mexico City Is Rapidly Running Out of Water


One of the world's largest cities (population 22 million) is rapidly running out of water. The causes include severe heat from climate change, aging infrastructure including a water procurement system that loses around 40% of its water to leaks, and massive overdevelopment  USA Today -- 

Glacial Lake Deluge  

 In 1941 a flood from a glacial lake in Peru killed as many as 5,000 people. Now as the climate warms conditions are right for an even greater glacial lake deluge in Peru. The Guardian.


The EPA Launches TCE Clean-up for Des Moines Area

The Environmental Protection Agency is launching clean-up efforts in Des Moines for a dangerous chemical known to cause cancer that is threatening the city's drinking water. The chemical Trichloroethylene is a known carcinogen; studies have linked it to liver and kidney cancers if consumed. It is believed the TCE contamination is the result of decades of industrial businesses dumping solvents containing TCE, like paint removers and degreasers, onto the land, allowing it to seep into water underground.

According to the Agency for Toxic Substances and Disease Registry, TCE has been discovered at 1,051 of the 1,854 sites on the National Priority List. Last year, the Biden administration proposed a ban on the chemical. The TCE  cleanup will be paid for by federal funds.  KCCI television. 

Does Higher Water Pressure Save Water?

Thought-provoking research reported by The Guardian indicates that people actually use less water showering when pressure is good than when flow is restricted.  Research seems to establish that while low flow-rate showers simply delivered less water than high flow-rate showers, high-pressure showers resulted in lower consumption because they were turned off sooner than low-pressure showers.

In case you missed it, Groundwater Awareness Week was observed from March 10 to 16.

Laundry Pods and Clothing Itself Are Major Contributors to Microplastic Pollution of our Water

"Some 60 percent of clothing today is made with plastic. Polyester, nylon, acrylic, spandex — they’re all just different types of fossil fuel-derived plastic fabric."  Manufacturing and laundering clothing made of plastic fabrics has become a massive source of microplastic pollution of the world's water.  Full Article.
 

 
 
The collapse of a major bridge in Baltimore in the early morning hours of March 26 due to a massive cargo ship collision has left multiple people dead and throttled one of the country’s biggest ports for the foreseeable future.This shocking story that will be in the news for months to come.  Here's a good overview of the tragedy.  CNN

 
How Trees Help Keep Water Clean

by Lin Taylor
LONDON (Thomson Reuters Foundation) – More trees at water sources improve sanitation and lead to fewer children dying from diarrhea in poor countries, a global study said on Monday.

The study examined the health of 300,000 children and the quality of watersheds across 35 countries including Bangladesh, Nigeria, and Colombia, and found that having more trees upstream led to healthier children.

“This shows, very clearly, how healthy ecosystems can directly support human health and welfare,” said co-author of the study, Brendan Fisher, a researcher at the University of Vermont in the United States.

“This suggests that protecting watersheds, in the right circumstances, can double as a public health investment,” he said in a statement.

The study, which analyzed U.S. foreign aid data spanning three decades, said increasing the number of trees by a third near the source of watersheds in rural areas could improve water sanitation as effectively as installing indoor plumbing or toilets.

“These findings clearly show that forests and other natural systems can complement traditional water sanitation systems, and help compensate for a lack of infrastructure,” said Diego Herrera, lead author of the study which was published in the journal Nature Communications.

Diarrheal disease, which is preventable, kills more than half a million children under the age of five each year, and is one of the leading causes of death in children along with malaria and pneumonia, the World Health Organization (WHO) says.

Lack of sanitation and clean water result in nearly 1.7 billion cases of childhood diarrheal disease every year, the WHO says.

 Source: Reuters.  Original Source Article is no longer available.
 
 
More about Trees and Water

 
Most Spruce trees are, by weight, about 20% water.
 
You've probably seen the charts that show how much water is contained in the makeup of everything from an orange to the human heart. Massive, solid trees are no different. Their mass is comprised of a significant amount of water. And like people, not all trees are equal in water content.

The Catalpa tree in my back yard, according to one source,  is, by weight, 48.25% water. Trees listed range from 7% to 54% water. 
 
 
 
 
 
 
 
 
 
 
 
Places to visit for additional information:

 
 
 
 
 
 
 
Thanks for reading. 
Pure Water Products, LLC, 523A N. Elm St., Denton, TX, 76201.  www.purewaterproducts.com. Call us at 888 382 3814, or email pwp@purewaterproducts.com.
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