Chemicals that keep drinking water flowing may also cause fouling

by Yun Shen et al

Research from The University of Illinois at Urbana-Champaign

Summary: Many city drinking water systems add softening agents to keep plumbing free of pipe-clogging mineral buildup. According to new research, these additives may amplify the risk of pathogen release into drinking water by weakening the grip that bacteria — like those responsible for Legionnaires’ disease — have on pipe interiors.

Many city drinking water systems add softening agents to keep plumbing free of pipe-clogging mineral buildup. According to new research, these additives may amplify the risk of pathogen release into drinking water by weakening the grip that bacteria — like those responsible for Legionnaires’ disease — have on pipe interiors.


Biofilms, which are similar to the films that grow on the glass of fish tanks, are present in almost all plumbing systems and anchor themselves to mineral scale buildups in pipes. They are teeming with harmless microbial life and incidents of waterborne illness are rare.

“The groundwater that supplies many cities may be high in magnesium and calcium,” said Helen Nguyen, a professor of civil engineering and co-author of the study. “When combined with other elements, they can form thick deposits of mineral scale that clog up engineered water systems. Because of this, water treatment plants add chemicals called polyphosphates to dissolve the minerals to keep the scale buildup under control.”

A recent study by co-author and civil and environmental engineering professor Wen-Tso Liu has shown that even with the addition of antimicrobial agents by water companies, the bacteria that grow on the mineral scale can reproduce to harmful levels in supplies that stagnate within indoor plumbing.

In a new study published in the journal Biofilms and Microbiomes, a team of University of Illinois engineers shows that the addition of anti-scalant chemicals cause the biofilms to grow thicker and become softer.

The team measured the thickness and stiffness of lab-grown biofilms using magnetomotive optical coherence elastography — a tool used to measure the strength of cancer tissues. The analytical method, developed by Stephen Boppart, a professor of electrical and computer engineering and study co-author, allowed the team to quantify the effect that polyphosphate has on the strength of biofilms.

To reproduce what happens in engineered plumbing systems, the team used PVC pipe and groundwater from the Champaign-Urbana area source to grow biofilms. They set up multiple scenarios with and without added polyphosphates. All scenarios produced biofilms, but the system that used polyphosphates grew a much thicker and softer biofilms than the others, the researchers said.

“Increased biofilm thickness means more bacteria, and the softening increases the chance that pieces will detach and foul the water supply under normal flow pressure,” Nguyen said. “Tap water is regulated by the Environmental Protection Agency up to the property line, not the tap. So, in buildings where water has been stagnating for a while, this could become a public health issue.”

A problem, according to researchers, is that some sort of anti-scalant chemical is required to maintain adequate water flow through pipes. “Of course, one solution could be to replace pipes once they become clogged with mineral buildup,” Nguyen said. “But that would be a very expensive endeavor for public utilities and property owners in a country as large as the United States.”

Nguyen believes that the most affordable and realistic solution will come through a better understanding of water chemistry, not by trying to kill all microbes, ripping out pipes or changing regulations.

“Before this work, we did not have a good understanding of the relationship between the water chemistry and microbiome that exists in plumbing. This work has given us initial insight and tools to help determine what chemicals will work best and at what concentration,” Nguyen said.

The team is moving ahead with related studies that look at ways to help physically remove biofilms while pipes remain in place and others that look at the effects of anti-corrosive chemicals on biofilms and water quality.

“We will not be able to control how long a drinking water user will allow water to stagnate, but we can work to understand how the chemicals we add to our water interact with biofilms.”

Reprinted from Science News.

Pure Water Gazette Fair Use Statement

Gazette Famous Water Picture Series

The Bluebird K7 Floats Again, After More Than 50 Years



Bluebird, the hydroplane that reached record-breaking speeds, has returned to the water for the first time in more than 50 years after it crashed killing its pilot, Donald Campbell.  The jet-powered boat was launched in a lake on Isle of Bute in Scotland or August 4, 2018.

Having broken eight world-speed records on water and land in the 1950s and 1960s, Campbell was attempting to break his own water-speed record of 276 mph when he was killed. The wreckage of Bluebird, with Cambell’s body, his race suit still intact, was pulled from the depths of the Cumbria lake in 2001. The boat was restored by volunteers.

Full story from The Guardian.

Pure Water Gazette Fair Use Statement

Here’s Why You Should Start Washing Your Clothes in Cold Water


Washing your clothes in cold water may seem counterintuitive to everything you’ve learned in the laundry room, but there are a host of benefits that come from turning down the heat on your washing machine.

Using cold water isn’t just better for your clothes and your wallet – it’s also better for the environment.

90% of the energy used in a typical washing machine goes towards heating the water. The other 10% is simply used to power the motor. According to Business Insider, washing machine manufacturers have spent the last 15 years improving their designs so their products can clean laundry more efficiently while still meeting hot water use standards that have been set by the Department of Energy.

As the manufacturers improved their designs, laundry detergent companies improved their recipes so their products could work more efficiently with cold water.

“Front-loaders and high-efficiency top-loaders run normal cycles 10 percent cooler than agitator washers, and the ‘warm’ wash temperature in the U.S. has declined by 15 degrees over the past 15 years,” Tracey Long, communications manager for Proctor & Gamble’s fabric care products in North America, told the news outlet.

“Traditional detergent enzymes can be sluggish in cold water so we worked to create a mix of surfactants and enzymes that deliver cleaning performance in cold water across all product lines,” she added.

So unless you’re washing fabrics that have been used by sick people, or you’re doing a load of dirty diapers, washing dirty clothes in cold water is just as efficient as using hot. According to Christine Dimmick, the author of “Detox Your Home”, you can add a half-cup of white vinegar to a load of smelly laundry to get the odor out. She also says you can add a little dose of essential oil if you’re adverse to the smell of vinegar.

Additionally, cold water is better for the longevity of your clothing, as it keeps them from wearing out, shrinking, or bleeding color.

If the average American washed 4 out of 5 of their laundry loads in cold water, they could save up to 864 pounds of emissions from the atmosphere every year, says Cold Water Saves. That’s the equivalent of planting .34 acres of trees in the US.

Plus, using hot water accounts for roughly $265 worth of electricity for the average American annually, in comparison to cold water only costing about $16.

Source: The Good News Network.

Pure Water Gazette Fair Use Statement

Filter for your washing machine.

Race Is On To Harness Nation’s Last Untapped Water Sources

by Sara Jerome

(Slightly truncated.)

As demand on water resources rises, will there be a mad rush to grab up the nation’s last untapped water resources?

That’s a looming fear for those who say the Great Salt Lake, the largest saltwater lake in the Western Hemisphere, may be at risk of drying up.

The lake is part of a large watershed that is used for drinking water within the most arid part of Utah.

The root of the problem, and the reason the lake is risk, is language in the Bear River Compact for the Great Salt Lake, an agreement written in 1958 and amended in 1980.

The agreement divides the Bear River between Wyoming, Utah and Idaho. If the states find a way to use all their allotted water, the Great Salt Lake could turn into toxic dust.

Under the agreement, water from the Bear River appears to be at least partially up for grabs by the three states. That puts the lake at risk because the river, an essential water source for the lake, could be tapped.

“The Bear River is one of the few remaining water sources in the western United States where large quantities of unclaimed water may be available. So with demand mounting in neighboring communities, [the] fear that someone is going to figure out how to use that water may become reality. If that happens, he said, it could reduce the Great Salt Lake to dust – toxic dust,” News Deeply reported.

Environmental activists, researchers, and public officials gathered in June to discuss the compact and the fate of the lake, but Wyoming and Idaho did not send representatives.

“Even with concern for the lake mounting, solutions that everyone can agree on will be hard to find,” News Deeply reported.

Craig Miller, a hydrologist with the Utah Division of Water Resources, discussed the need to find an intervention.

“It’s a slow-moving train,” he said, per the report. “We can step off the tracks, but we have to take action. We can’t sit back and say that will never happen.”

As far as the big picture of water use in the U.S., reports from the U.S. Geological Survey are especially useful. These reports represent the longest record of water use data in the U.S.

Thermoelectric power, irrigation withdrawals, and public-supply withdrawals represent 90 percent of total water withdrawals in the U.S., according to the U.S. Geological Survey. The trends in withdrawals for these purposes are as follows:

  • Thermoelectric power decreased 18 percent between 2010 and 2015, the largest percent decline of all categories.
  • Irrigation withdrawals (all freshwater) increased 2 percent.
  • Public-supply withdrawals decreased 7 percent.

Source: Water Online.

Pure Water Gazette Fair Use Statement

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.







Compact Retention Tanks



Advanced Retention Tank, outperforms tanks twice its size by relying on enhanced mixing strategies.

Retention tanks play a vital role in water treatment. Their main function is simply to “retain” water being treated long enough for the treatment process to take place. Water treatment chemicals need residence time to do their job. Chlorine, for example, does now work by magic. Whether it is used to control pathogens or perform reactions that facilitate removal of such contaminants as iron and manganese, chlorine usually needs several minutes of contact time with the targeted contaminant. The function of the retention tank is to provide that time.

In residential water treatment, retention tanks of 80 to 120 gallons are commonly installed after the chlorine injection point to allow chlorine time to mix thoroughly with the water and do its work. Oxidizers like ozone and hydrogen peroxide need less time and are used with smaller retention tanks or sometimes with no retention tank at all.

Large tanks are expensive to ship and take up space. A conventional 120 gallon retention tank, for example, is 24″ in diameter x 80″ high. It has to be transported by motor freight, occupies lots of floor space, and typically has a connection size that has to be reduced for use with standard 1″ residential piping. Getting such a tank through a tight door or down stairs into a basement can be a challenge.

Compact Tanks

There are some new tanks on the market that really fill a need. While they aren’t quite the mythical tank that’s bigger on the inside than on the outside, they go a long way in that direction. They require half the floor space of conventional holding tanks and can be set in place without a fork lift.

The new style retention tanks are smaller, easier to transport and generally easier to install. They require a fraction of the floor space of conventional tanks and have been shown to outperform tanks that are much larger in size.

The secret is the inclusion of inner mixing and swirl chambers that can reduce a drop of water to hundreds of micro bubbles, allowing chemical reactions to take place five times as fast as with conventional retention tanks. In a sense, they are tanks with mixing enhancers built into the tank rather than installed externally, like static mixers, for example.


Inner Swirl Chambers and Mixers blend treatment chemicals with the water quickly to cut retention time significantly.

The tanks shown below all use 1″ in/out ports and have a 3/4″ blow-down valve installed at the bottom of the tank for easy clean-out.

Of the tanks listed below, the 12″ unit is recommended for most residential chlorine applications. The smaller tank is for use with ozone and hydrogen peroxide or very low-flow chlorine applications.


Standard, Single-Chamber Tanks

Part Number, Description GPM Port Size Equivalent Conventional Tank Size Price
WH426 – Compact Retention Tank, 10″ X 47″ 25 1″ 80 gallons $465.00
WH420 – Compact Retention Tank, 12″ X 48″  (12″ x 60″ full size including base and cap.) 25 1″ 120 gallons $530.00

These work for most residential applications.  Larger tanks are available, including enhanced versions with multiple mixing chambers.  Please call for information and pricing for larger models.

The tanks on this page are at present “call to order” products that will soon be on our main website.

To call to order, or for more information: 940 382 3814.

Residential Chloramine Cartridge Filters



Below are specially priced cartridge-style chloramine filters, all using the exceptional Pentek CRFC20-BB Chloramine Reduction Radial Flow Carbon Cartridge. We’re convinced that this cartridge, though it costs a little more than other chloramine cartridges we have available,  offers the best value in residential and small commercial chloramine removal. The unique radial flow granular style CRFC2–BB provides long life and minimal pressure drop, as compared with carbon block chloramine cartridges.

The package systems we’ve put together include a filter wrench, housings, extra O Rings,  brackets, and cartridges.  All housings have 1″ ports (3/4″ or 1.5″ available upon request).  All housings, both 20″ and 10″,  are tough, reliable Pentek “Big Blue.”  All housing packages include mounting screws, heavy duty metal brackets, and one extra housing O Ring.

These systems are designed for parallel installation of the chloramine filters to assure minimal pressure drop and optimal chloramine performance. See the reference pages listed below for installation pictures. Note that all chloramine filters are 20″ and all sediment filters are 10″.



Price (shipping to lower-48 addresses included)

System 1. One 4.5″ X 10″ 5 micron sediment filter plus 4.5″ X 20″ Chloramine Filter Homes with 1 or 2 people. Flow rates to 5 gpm. $349.00
System 2. One 4.5″ X 10″ 5 micron sediment filter plus two 4.5″ X 20″ Chloramine Filters installed in parallel. Homes with up to 5 people. Flow rates to 10 gpm. $599.00
System 3. One 4.5″ X 10″ 5 micron sediment filter plus three 4.5″ X 20″ Chloramine Filters installed in parallel. Homes with up to 8 people. Flow rates to 15 gpm. $849.00


 wh101_306Basic 20″ Big Blue Housing


Multi-filter installation. Water passes through sediment filter on the left, then splits to pass through two chloramine filters.  (Filters on this page use a 10″ Big Blue sediment filter–half as long as the housing in the picture.)

See also:

High Performance Cartridge-Style Chloramine Filters.

Chloramine Removal (our testing of our own products).

Compact Whole House Filters.

More Multi-Filter Installation Pictures.

General Installation Instructions for Compact Whole House Filters.


Posted July 12th, 2018

ChemSorb, the Name, Bites the Dust


One of our favorite products, ChemSorb, a natural zeolite filtration medium capable of filtering out particulate down to about five microns, is undergoing a name change.  Due to a trademark conflict, the popular sediment filter medium is changing its brand name. The new brand name is not yet available.

The product is still for sale, but it will no longer be called ChemSorb.

Since at present it is a product without a name, we’ve changed our main website so that it is now sold simply by the generic name Zeolite,  So until a new name appears, if you want what used to be called ChemSorb,  please order Zeolite. It’s the same product (and the bag may even say ChemSorb), but our website now calls it Zeolite.

The Gazette’s Famous Water Picture Series: Step Wells



The famous step well called Chand Baori. 

(Click picture for larger view.)

Built in Rajasthan (India) around 850 AD, it was dedicated to Hashat Mata, Goddess of Joy and Happiness. Chand Baori, built in an arid region, was designed to conserve as much water as possible. Temperature at the bottom of the well is five or six degrees cooler than at the surface, so the well was used as a community gathering place during times of extreme heat.



stepwell01This recently built “step well” responds to the need to access water regardless of the water level. Step wells have been used in India since as early as 200 AD. The well in the picture is in the village of Modi.  Such wells serve not only as a very practical source of water. They often demonstrate artistic and architectural innovation,  have religious, cultural and social significance, serve as village meeting places, have significant artistic value and promote local business by attracting tourists. 


Posted July 1st, 2018

Dams–the Benefits and the Risks.


New York State has at least 5,352 functioning dams, 861 of which are owned or co-owned by local governments. Dams, which are barriers that hold back flowing water, serve many purposes. Some exist primarily for flood control. Many create ponds or lakes used for recreation, or reservoirs used to manage water supplies. Some generate hydroelectric power. Management of the large number of dams in the state of New York is no small matter, since a dam not only can be a valuable asset but it also represents a considerable public risk.

New York currently considers that 19% of its 5,352 dams represent a high or intermediate hazard to public safety.  That is, failure of such dams could cost many lives and much property damage.

The deadliest dam failure in U.S. history occurred in 1889 in Johnstown, Pennsylvania, when a breach led to flooding that killed more than 2,200 people. Just last year, in Northern California, authorities issued a mandatory evacuation order for approximately 188,000 residents living downstream from the Oroville Dam after heavy rains increased water levels, and concerns about its spillways led to fears of uncontrolled releases of water.  A breach in a large dam in New York could cause severe downstream flooding spanning multiple counties. For example, a complete failure of the Gilboa Dam, which can store up to 19.6 billion gallons of water, could devastate downstream communities in Schoharie, Montgomery and Schenectady counties, including the villages of Middleburgh, Schoharie and Esperance. A breach could also cause flooding along the Mohawk River and into the Hudson River.

Dam safety requires regular attention. Floods can cause serious damage very quickly. More generally, risks can increase over time, not only because structural concerns such as cracking, settling, or “piping” (internal erosion caused by water infiltration through an earthen dam) can develop and worsen, but also because any increase in development downstream means that more people and businesses may be in harm’s way should something go wrong.

A dam that once posed little risk to human life, because its failure would result only in flooding of farm fields or vacant land, becomes a greater threat once the land has been developed and people live and/or work there.16 New York’s high-hazard dams have an average age of 89 years; those classified as intermediate hazard are 83 years old on average.

Climate change is also likely to increase the risks dams pose. Global warming increases the frequency and severity of storms and accelerates the melting of the winter snow pack in the mountains, potentially subjecting dams to conditions that exceed their design specifications.

A relatively new – and growing – threat is sabotage carried out through cyber attacks. Dams operated by online controls have proven vulnerable to hackers. In 2013, a cyber attacker infiltrated the control systems of a dam in Westchester County.  The federal Environmental Protection Agency (EPA) helps water utilities improve their cyber security and manage risks associated with other types of terrorist threats.

This article is indebted to a study done by the Comptroller of New York state.  See the full report, with graphs and charts.

Much more about dams from the Pure Water Gazette.