Bird And Fish

Pure Water Occasional

An Email Publication About Water and Water Treatment

February 2011

In this brand new Occasional you'll hear about a private waste dump in South Dakota, cation and anion exchangers, the Circle of Blue, and gasoline-contaminated water in Baltimore. Perchlorate, fracking, phosphorous overuse, mysterious calcium slime, and a highly touted "device" called SAFL Baffle. Learn how many children die each day from preventable water-related illnesses, how many small dams there are in the US and how many large dams there are in China, plus the names (and addresses) of the ten US cities with the worst drinking water. As always, more about hexavalent chromium. On top of that, you'll hear about a new law against shark fin possession and learn how fish are being used as water testing devices. You'll hear more than you want to know about what filter carbon does and doesn't, how to remove cryptosporidium, giardia, and radon from water, and, as always, much, much more.

The Occasional is overseen by Pure Water Gazette editor Hardly Waite. Thanks for editorial assistance for this issue by Beth Rutter.

To Read This Issue Online.

Hardly Waite

While you were filling out your Valentine cards and shivering, a lot of important things happened in the world of water. To hear all about it, read on.

Water News for February 2011

The EPA announced that it is establishing a drinking water standard for the rocket fuel perchlorate.

California's lush Westlands Water District is facing a water crisis that threatens one of the nation's prime sources of agricultural products.

The cities of Delaware and Marysville, both in Ohio, have discovered that treating their municipal water supply with reverse osmosis leads to complex and costly disposal problems.

Ohio RO Unit
Giant RO Units Used to Treat Municipal Water In Ohio

A Clemson University soil expert was brought in to determine the safety of a Pelion, SD private waste dump that has for 22 years been discharging human waste and restaurant grease onto the ground. Water in the area is poisoned with nitrates.

The U.S. Environmental Protection Agency (EPA) submitted a draft study plan on hydraulic fracturing for review to the agency’s Science Advisory Board (SAB), a group of independent scientists.

Gasoline-contaminated drinking water caused the closing of a Baltimore area school.

Citizens of Fair Play, SC protested vigorously in attempt to stop the construction of a proposed water treatment plant.

Thieves dug a tunnel under concrete to steal tens of thousands of dollars worth of equipment from the Hamilton City Council's water treatment plant. Among the stolen items were 10 bronze water pump impellers. Two of the impellers were valued at $60,000 to $80.000.

Lawmakers in California are considering a law to ban the possession of shark fins.

New York City has undertaken a mammoth tunnel system. It links with a 120-year-old aqueduct and a one-of-a-kind filtering plant in the Bronx. A major engineering feat, it is designed to provide safe and excellent water for the city for years to come.  Article highly recommended.

A judge in a small jungle town in Ecuador ordered Chevron to pay more than $9 billion in damages, finding the energy giant responsible for the oil pollution that has fouled a stretch of land along Ecuador's northern border. Chances that Ecuador's poor, whose land has been ruined by US oil exploitation, will actually collect any damages? Virtually zero.

The world is running out of phosphorus, largely because of industrial and agricultural overuse. The outrageously wasteful overuse of phosphorus-based fertilizers has created a major source of water contamination.

Research in Great Britain concluded that children with eczema were not helped by bathing in ion exchange softened water.

A Nevada lawsuit charges that wells once used for drinking water are polluted with uranium, arsenic and other metals because of decades of chemical leaks from a mine owned and operated by British Petroleum.

High tech devices called fish are an old standby in monitoring water quality.

A Japanese company has developed a bicycle water purifier that can treat up to 5 liters per minute.

The increased use of hand pumps in rural India has lead to increased use of ground water which in turn has caused an increase in fluoride intake which in turn has caused a spurt in fluorosis disease in several Indian states. Limb deformities [skeletal fluorosis] have been more pronounced among the young.

Scientists in Minnesota have developed a device that is said to prevent harmful sediment from entering lakes and streams. The device, called SAFL Baffle, works by slowing down water runoff, thereby preventing the water from picking up harmful sediments. It is pictured below. See if you can figure out how it works. (We can't.)

Safl Bafle

The Administration's new budget proposes a13% decrease in funding for the EPA.

There's a new list of the ten American cities with the worst drinking water.

The EPA is considering a study of fracking in our home county. We hear complaints almost daily from local well owners.

The wastewater treatment system of Jerome. ID has been taken over by a mysterious slime.


More About Hexavalent Chromium

The contaminant that has recently caught public attention, Chromium-6, has spawned much activity in the water treatment community.

Many strategies for reduction of Chromium-6 have been featured in journal articles.

For removal of Chromium-6 from small amounts of drinking water, reverse osmosis is the obvious choice. However, for large-scale operations (like city water plants) RO is way too expensive. Most of the attention for Chromium-6 treatment of large amounts of water has centered on anion exchange.

Anion exchangers resemble water softeners (cation exchangers) except that they use resins that specifically target anions, negatively charged ions. Anion exchangers are regularly used, for example, for reduction of nitrates and correction of color problems caused by tannins.

Removing Chromium-6 with anion exchange isn't simple. Several resin types can be used, but in most cases regeneration is difficult and it often produces yet another waste product that is difficult to dispose of. The most promising technology, according to a recent Water Technology article, is a disposable anion resin that is not regenerated but is used to capacity and disposed of. Even this treatment has difficulties. It is necessary to lower the pH of the water to assure effective treatment, for example.This alone makes the method an unlikely option for residential applications.

The article concludes:

"As effluent discharge regulations become more stringent, the ion exchange method of chromate removal using a selective, high-capacity, single-use resin becomes more attractive. Chromate pollution over the years from plating operations and corrosion control has contaminated many groundwater sources. A selective chromate resin is an economical remediation technique in many of these applications."

Ten Things You Should Know About Water

According to an article from the interesting and informative Circle of Blue website, there are ten things you should know about water. The author does not indicate if these are the ten most important things you should know or if they are ranked in order of importance. Here they are:

10 Things You Should Know:

1 – One drop of oil can make up to 25 liters (6.6 gallons) of water undrinkable.

2 – Seventy percent of the world’s water is used for agriculture, 22 percent for industry and 8 percent for domestic use. Low and middle income countries use 82 percent of their water for agriculture, 10 percent for industry and 8 percent for domestic use. High income countries use 30 percent of their water for agriculture, 59 percent for industry and 11 percent for domestic use.

3 – A person is able to survive one month without food but only five to seven days without water.

4 – Of all the Earth’s water, 97.5 percent is salt and 2.5 is fresh. Of that water, about 70 percent is locked in glacial ice and 30 percent in soil, leaving under 1 percent (.007 percent of the total water) readily accessible for human use.

5 – A water footprint, or virtual water, is the amount of water used in the entire production and/or growth of a specific product. For example, 1 kilogram (2.2 lbs) of beef has a water footprint of 16,000 liters (4,226.8 gallons); one sheet of paper has a water footprint of 10 liters (2.6 gallons); one cup of tea has a water footprint of 35 liters (9.2 gallons); and one microchip has a water footprint of 32 liters (8.5 gallons).

6 – It takes 94.5 to 189.3 liters of water (25 to 50 gallons) to take a five-minute shower; 7.6 to 26.5 liters (2-7 gallons) to flush a toilet; 7.6 liters (2 gallons) to brush one’s teeth; and 75.7 liters (20 gallons) to hand wash dishes.

7 – 6,000 children die each day from preventable water-related diseases.

8 – The population of the United States is approximately 304 million; the population of Europe is approximately 732.7 million; 1.1 billion people lack adequate drinking water access; and 2.6 billion people lack basic water sanitation.

9 – The average American uses about 575 liters of water (151.9 gallons) per day, with about 60 percent of that being used out-of-doors (watering lawns, washing cars, etc.). The average European uses 250 liters of water (66 gallons) per day. 1.1 billion people lack adequate water access, using less than 19 liters (5 gallons) per day.

10 – The average American uses 30.3 times more water than a person who lacks adequate water access; the average European uses 13.2 times more water than a person who lacks adequate water access.

Carbon Filtration: What It Does, What It Doesn't

by Gene Franks

The main ingredient of most home water treatment devices is filter carbon. It is referred to variously as carbon, filter carbon, or GAC (granular activated carbon). Customers frequently call it "charcoal." Filter carbon is a manufactured product that is made from such raw materials as various types of coal, wood, nut shells, and even (much less frequently) animal bones. Without filter carbon, the extensive water treatment that is practiced today would not be possible.

The largest single section in the EPA's "Regulated Water Contaminants” chart is the section on Organics (including VOCs, or “Volatile Organics”). In this category the EPA lists more than thirty very nasty chemical contaminants—many with familiar names like benzene, 1,1 dichlorethylene, carbon tetrachloride, dioxin, styrene, toluene, chloroform, and vinyl chloride. To give an idea of the scope of this category, a single one of the 30 plus items is “Total Trihalomethanes,” a category made up of still uncounted chemicals, assumed to number in the thousands, that are formed when water containing organic matter (i. e., virtually all surface water) is treated with chlorine. These are potent chemicals. The maximum allowable level for trihalomethanes, which are suspected cancer causers and are present in virtually all chlorinated tap water, is only 1/10 of one part per million.

For the Organics category, the primary treatment in all cases and the only recommended treatment in most cases, is activated carbon.

The EPA’s Pesticides category lists more than a dozen familiar poisons such as Aldicarb, Chlordane, Heptachlor, and Lindane. In all cases, activated carbon is the only recommended treatment.

Of the 12 Herbicides listed (2,4-D, Atrazine, etc.), activated carbon is the only treatment recommended.

For Organics, Pesticides, and Herbicides, the standard treatment, and in most cases the only treatment recommended, is activated carbon.

What carbon filtration does not do can be seen in the remaining three categories of the EPA contaminant list. Carbon is mentioned as a treatment for only one of the four listed Microbiological contaminants listed--turbidity.

It is not recommended for coliform removal or for cysts, though ironically, some of the very tight solid carbon block filters now on the market remove bacteria (though manufacturers seldom make this claim). Cysts like giardia and cryptosporidium are quite easily removed, though not by the adsorptive activity of carbon, but by the straining capacity of the filter. Multi-Pure solid carbon blocks, in fact, were the first filtration device certified by NSF for removal of cryptosporidium. Many very tight carbon block filters remove cysts simply because of their restricted pore size. Some microbes are simply too fat to fit through the pores.

Nevertheless, carbon is not usually regarded as a treatment for microbes.

The same is true in the Inorganic category. Activated carbon itself appears in the EPA list as a preferred treatment only for mercury, but carbon block filters can also be engineered to remove lead and arsenic. By and large, however, removal of inorganics is the province of reverse osmosis, distillers, and ion exchange systems.

The same is true in the final category, Radionuclides, where carbon is ineffective and reverse osmosis (RO) and ion exchange are definitely the treatments of choice.Of the most prominent radionuclides, only radon is regularly treated by carbon filtration.

The chart below addresses most of the frequently asked questions concerning applications of filter carbon. The list isn't meant to be complete and there are some intentional overlaps.

What Carbon Reduces and What It Doesn't

Is Carbon a good treatment for ...?





This is what coconut shell carbon is best at.



Best and often the only treatment.



Best and often the only treatment.



Best and often the only treatment.


No, with qualifications.

Carbon is not a recognized treatment for bacteria, although carbon blocks can be made so tight that they screen out bacteria. Silver impregnated carbon is marketed as "bacteriostatic." This does not mean that it purifies non-potable water but that the added silver can inhibit the growth of bacteria in the carbon bed. The same is true for KDF, which is said to have "bacteriostatic" properties.

Cysts (Giardia and Cryptosporidium)

No, with qualifications.

However, many carbon block filters have cyst certification because they are tight enough to screen out cysts effectively.


No, except mercury.

Carbon block filters, however, are often engineered to remove lead by the adding a lead removal resin to the carbon. Arsenic reduction media can also be added to carbon filters.


No, with qualification.

This is a difficult classification. According to the EPA, "Approximately 2,300 nuclides have been identified; most of them are radioactive." The two most frequently at issue in water treatment, Radon and Uranium, are included separately in this listing.



Aeration is usually preferred to carbon filtration because the spent carbon itself becomes hazardous waste.

Hydrogen Sulfide (Rotten Egg Odor)

Yes, with qualifications.

Lifespan of carbon can be limited if the H2S is not pretreated with an oxidizer. Catalytic carbon is superior to standard for H2S treatment.


Yes, with qualification.

Backwashing standard carbon filters remove pre-oxidized iron. Catalytic carbon can remove reasonable amounts of unoxidized iron.

pH correction

No, with qualification.

Almost anything done to water affects pH, but carbon is not used to raise or lower pH.

Calcium and Magnesium (hardness)


Only water softeners, reverse osmosis, and distillers actually remove hardness.



Only water softeners, reverse osmosis, and distillers actually remove sodium.



Only reverse osmosis, distillers, and anion exchangers affect nitrates.


No, with qualifications.

Carbon sometimes removes fluoride, but it is not a reliable fluoride treatment. A specialty carbon made with animal bones (Bone Char) is used in some parts of the world to remove fluoride.

Taste and Odor


Carbon is the unchallenged best treatment for most taste/odor problems. Carbon filtration improves the taste of most waters.


Yes, with qualifications.

Macropore carbon (usually made of Eucalyptus and currently hard to find) is an effective treatment for tannins. Lignite based carbon is also used for tannins. Standard carbon may help.

TDS (Total Dissolved Solids)


Carbon does not reduce dissolved minerals. In fact, carbon filtration may add slightly to the TDS reading.



Only when accompanied by arsenic reduction resins.



MTBE (gasoline additive)


Coconut shell carbon is preferred.



Much longer contact time is needed for chloramine than for chlorine. Catalytic carbon is superior to standard carbon for chloramine reduction.

Uranium No  



Carbon converts chlorine to harmless chloride. This is what carbon is best at.

If there is a question about how to reduce a specific water contaminant, you can find information on most in the Occasional's Water Treatment Issues section.

Pure Water Annie

The Ups and Downs of Filter Cartridges

by Pure Water Annie

Good and sincere advice from the Occasional's Technical Department.

Here Pure Water Annie demystifies one of the great mysteries of filter cartridge replacement: Which end goes up?

One of the most frequent calls we get from customers who are replacing cartridges in their filters or reverse osmosis units concerns the up and down of installation--which end goes up in the housing.

Here's a picture of various types of filter cartridges that I'll use to explain:

Cartridge Size Chart

In this discussion we're skipping the obvious. In the picture, the candle style (includes Doulton Candles, Multi-Pure cartridges,and some carbon blocks) and the Q Series cartridge screw into their housing. You screw the part with threads into the other part with threads. No explanation should be needed. The Inline cartridge has no housing, but you need to observe the direction flow arrow (some are hard to find).

This leaves us the cartridges that go in standard housings. Standard cartridges fall in two categories: radial flow and axial flow.

Radial Flow Cartridges have no up or down. The 4.5 X 20 is a radial flow carbon block. Water flows from the outside of the cartridge though the wall to the center, then exits the housing from the center of the cartridge. Cartridges marked 9.75 X 4.25 (a "pleated" sediment cartridge) and 2.5 X 20 (a "melt blown" sediment cartridge) are also radial cartridges. Water flows from the outside, through the wall, and exits from the center. With these cartridges, it doesn't matter which end goes up in the housing. The most important thing is to keep them centered so that the knife-edge seals built into the filter housing can seat properly.

With Axial Flow Cartridges, the correct up and down orientation must be followed or the cartridge simply won't work. An axial flow cartridge is one in which the water enters one end and flows through the entire length of the cartridge to exit at the other end. The blue cartridge in the picture is the only standard axial. Axials, which are normally granular media filters, may have an end gasket on only one end (some have two) and one end (the one with the gasket) is often smaller in diameter.

The "which end goes up" difficulty comes from the facts that manufacturers have no standard way of labeling and the axial cartridges can be used in undersink-style housings and countertop-style housings. The cap of an undersink filter serves the same function as the base of a countertop filter.

Here are the rules:

The narrow end of the axial filter goes toward the cap or base.

The wider end of the cartridge. which often has slits for water to enter around its perimeter, goes into the "sump"-- the long part of the filter housing.

Manufacturers of cartridges, for some reason, assume that the cartridge will be installed in an undersink (cap up) filter. Their labels often say, "This end up." This really means that this end goes up in an undersink filter but down (toward the base) in a countertop filter.

The best news about all this is that if you get the cartridge in upside down, it won't hurt do any damage, and you'll know it right away because no water will go through the filter.

If water won't flow through the axial cartridge, you have it upside down.

How to tell an axial from a radial. The easy way is to look through the center hole as if you were looking through a telescope. If you can see through,it's a radial flow. If you can't it's an axial.




Pure Water Gazette numerical wizard B. Bea Sharper reports the water facts that Harper's misses.

On Dams and Some Other Things

Elevation below sea level of the Dead Sea, the lowest place on Earth: 1400 ft.

Feet by which groundwater levels in Mehdigan, India have dropped since Coca Cola, promising great benefit to the city, began its bottled water operation there: 40.

Number of Gandhre, India villagers whose water needs could be met by the water that Coca Cola withdraws for its bottled water operation there: 75,000.

Fraction of participants in a 2007 CBS News-sponsored taste test who preferred the taste of tap water over bottled water: 2/3.

Percentage of bottled water sold across state lines that is regulated by the FDA: 30 to 40 percent.

Barrels of oil required each year to support the annual U. S. plastic water bottle production: 17,000,000.

Number of automobiles that could be fueled with this oil: 1,000,000.

Percentage of US plastic water bottles that are not recycled: 86%.

The year that Hoover Dam, considered the first modern dam, went into service: 1935.

Square miles covered by the state of California: 163,707.

Square miles covered, collectively, by the world's dam reservoirs: more than163,707.

The estimated number of large dams around the world: 50,000- 54,000.

Number of large dams in China: 22,000.

Number of large dams in India: 3,600.

Number of small dams in the United States: 99.000.

The amount of the world's food production made possible by the water that dams store: 1/6.

Now, the age of consequences has arrived, and it is becoming increasingly clear that dams' benefits are temporary, while the damage that they inflict on societies and landscapes approaches permanence.--Jacques Leslie

Estimated number of environmental consequences that the tiny African country of Lesotho has suffered because of changes of water flow caused by its dam: 20,000.

According to the World Commission on Dams, total number of people who have been driven from their homes by dam construction:: 40 – 80 million.

Number of people killed by a 1967 Indian earthquake blamed on the weight of a dam's reservoir: 180.

The number of people who were drowned in 1963 by a wave created by seismic activity blamed on the filling of a dam reservoir in Vaiont, Italy: 2,600.

Number of unsafe dams in the US, according to a 2008 civil engineering study: 3,500.

Percentage of dams that are privately owned in the United States: 56%

Amount that the Chinese government's Exim bank has loaned for the Merowe Dam project in Sudan: $520 millions.

Number of poor Sudanese that the Merowe Dam is expected to leave without homes: over 50,000.



Suggested reading this month from the Pure Water Gazette's archive: Whose Water Is It? Water Rights in the Age of Scarcity, by Peter Gleick.

Model 77: "The World's Greatest $77 Water Filter"
Sprite Shower Filters: You'll Sing Better!
An Alphabetical Index to Water Treatment Products

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