How Nitrates Are Removed from Drinking Water

Although nitrogen occurs naturally in the environment and is necessary to support plant life,  nitrates can become serious water contaminants.

When taken into the body, nitrates convert to nitrites and are the cause of a number of serious ailments, the most known being “Blue Baby” syndrome.

The main source of nitrates in drinking water is agricultural fertilizer. Other sources include human sewage and livestock manure. Please refer to the  Pure Water Products’ Nitrate Factsheet.

The EPA, which sets a Maximum Contaminant Level for nitrates at 10 parts per million, recommends two methods for removing nitrates from water–reverse osmosis and ion exchange.

For drinking water in the home, reverse osmosis is the most common and easiest to apply.  A simple undersink reverse osmosis unit easily removes 95% or more of nitrates from tap water.  Small home distillers can also remove nitrates, as can specially designed ion exchange cartridges for standard water filters.

For larger amounts of water, from single residence wells up to small municipal sizes, the most common removal techniques is ion exchange.

Municipal water treatment plants also resort to blending,  a technique by which water with a high nitrate content is mixed with water with a lower content to produce a blend that meets standards.

Ion exchange, in the case of nitrate reduction,  is more precisely anion exchange. The ion exchange system used for nitrate removal is very similar to a water softener but instead of using softening resin,  which is a cation ion exchange resin, nitrate removal systems use an anion exchange resin. Both systems use sodium chloride salt (brine) to regenerate the ion resin bed.

Nitrate removal is not as simple as hardness removal. Two basic types of anion exchange resin can used, either Strong Base or Nitrate Specific. The latter is more expensive, costing usually about 50% more,  but simpler to use. It is frequently used by private well owners because it is more easily managed.

A Type II Anion (strong base) is best applied to municipal supplies where there is regular testing and maintenance of the system. Because Type II Anion resin is not nitrate selective there will be other ions, primarily sulfate, that compete for the exchange site. To properly size up this system, a complete water analysis will be required to ensure complete compliance and avoid nitrate “dumping” as the system approaches exhaustion. The nitrate level during dumping can be many times higher than the untreated nitrate concentration.

Nitrate selective anion resin is an option used principally on smaller municipal systems and private well sources. Nitrate selective anion resin strongly prefers the nitrate ions to the competing sulfate ions. With this resin we avoid nitrate “dumping”. In general this resin may be up to 50% more in cost.

Reference:  reschem.com.

Nitrate Levels in Drinking Water Are Increasing

 

Water News in a Nutshell.

 

In a Nutshell: Ever-increasing amounts of chemical fertilizers and animal manure are being swept into rivers causing alarming increases in nitrate levels in the drinking water of  farming states like Iowa, Illinois, and Minnesota.  Nitrates are no longer only a well-water problem.  Cities like Des Moines and Cedar Rapids get their drinking water from nitrate-laden rivers and are now facing difficult and expensive removal procedures. The unsavory trade-off is that corporations get cheap corn and citizens get high-priced, low-quality drinking water. 

In Iowa, nitrate levels in water have reached levels never seen before.

After a long drought, a soggy spring washed fertilizers and manure off of farms and into the rivers that provide drinking water. The elevated nitrate levels are becoming a threat to human health.

According to an AP article:

Nitrate levels have soared because drought-withered corn plants didn’t suck up all the nitrogen spread on fields last year. The drought was followed by Iowa’s wettest April in 141 years, and that rain washed unused fertilizer into rivers, the primary source of drinking water for 45 percent of the state’s population.

Nitrate in water is an issue throughout the Midwest, but Iowa is especially vulnerable because about 90 percent of the state is dedicated to agriculture. Corn requires an abundant supply of nitrogen, which must be added to the soil through the application of nitrogen fertilizer or manure. 

The Environmental Protection Agency requires nitrate in drinking water be kept at less than 10 milligrams per liter. Above that level can be deadly to infants younger than 6 months because the chemical can reduce the amount of oxygen carried in their blood. Pregnant women are advised not to drink water above the EPA limit, as are adults with reduced stomach acidity. There is conflicting evidence and expert opinion regarding nitrates as a cancer causer.

Without careful management, corn in the field can turn to nitrates in the water.

One river in Iowa, the Racoon River upstream from Des Moines, had nitrate readings of 24 mg/L last year. The Des Moines River reported a record high 18 mg/L.  Both rivers furnish drinking water for Des Moines. The city of Cedar Rapids has also experienced high levels of nitrates.

Many city water plants lack the equipment needed to reduce nitrate levels and are reduced to blending high nitrate water with water of better quality to produce an acceptable (below 10 mg/L) product. Other cities, like Des Moines, have expensive nitrate reduction equipment but prefer not to use it because of high operating cost.

Iowa and Illinois rivers typically have some of the nation’s highest nitrate levels, but other top corn states also have issues, including Indiana, Michigan, Minnesota, Ohio, Wisconsin and the eastern portions of Kansas, Nebraska, North Dakota and South Dakota.

According to the AP article cited above, nitrate levels in those states have been rising since the 1950s but leveled off in the 1980s. In the last five years, they’ve been climbing again as high corn prices have driven farmers to plant near-record corn acres. One official said: “In essence what we’re doing is subsidizing cheap food,  paying for it through the high cost of cleaning up our water after it’s contaminated by fertilizer.” 

And the cost indeed is high.  Des Moines has now had to switch on a $4 million nitrate reduction system that costs $7,000 per day to operate. In some Minnesota cities, the price of water has risen dramatically.

The nitrate invasion is, of course, the logical result of an unsustainable agricultural system that is focused entirely on short-term profits without regard to the consequences.  Farmers are being encouraged to limit fertilizer use and to leave plants in the field to lessen erosion, and  many have made changes.  But for most, it’s agribusiness as usual and the rivers be damned.

While it is difficult for city water suppliers to remove nitrates from the millions of daily gallons they process, it is relatively easy for homeowners to remove nitrates from drinking water. Reverse osmosis removes nitrates handily.

Source Reference: Article above drew information from a 2013 article from PostBulletin.com.

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 Rockwell City, Iowa — In older communities cracks in water pipelines often allow ground water to seep into water treatment systems. At Rockwell City’s waste water treatment plant it’s currently taking in more water than what is produced by the water treatment facility. Preliminary steps to solve the problem were taken at Monday’s city council meeting. Before any work is done crews will send cameras down into the pipelines and televise images back to workers. They’ll be able to see the amount of cracking and determine if the pipes are straight or bent. Once the amount of damage is determined the city could potentially slip line the current piping system to solve the problem. Estimated costs for a portion of a slip lining project could run upwards of $700,000.

The water main on High Street, however, will need to be replaced in the near future. Three to four city blocks of pipeline, including a section which passes under old Hwy 20, have seen constant repairs over the past few years. The lines will now be dug up and replaced at an estimated preliminary cost of around $200,000. Some of that cost will include the replacement of the road the pipes run under.

Reference Source:  CBC Online.

 Many of the Nation’s Water Treatment Facilities Are Long Overdue for Upgrade

According to the Environmental Protection Agency,  nearly $400 billion in infrastructure spending is needed over the next twenty years to ensure that Americans continue to have safe drinking water.

Pure Water Annie’s Extra-Simple Instructions for Changing Filter Cartridges in Standard Drinking Water Systems

This article addresses cartridge change for water filters and reverse systems with standard filter housings, like those pictured below.  If you have a proprietary (unique) system like Aquasana or Multipure,  you’ll have to figure out how to get the unit apart, but the rest of the instructions apply in a general way.

Some things that you’ll want to have on hand before you start, in addition to the replacement cartridges: a filter wrench, if needed, replacement O rings (though you may not need them), and silicone lubricant, though you won’t need this, either, if the O rings seem sound and sufficiently lubricated.  Also, a pan or, better, a towel to catch drips. A flashlight to look for leaks is also nice to have.

To start, turn off the water that goes to the water filter and lock open the faucet.  If no water is coming out of the faucet, it’s safe to open the housing to change the cartridge.  With reverse osmosis units you need also to turn off the valve on top of the storage tank.  (If your RO unit has no shutoff valve on the tank, you’ll have to let all of the water drain out of the tank.  While it’s draining, you’ll have time to reflect on the folly of buying the cheapest RO unit you could find.)

With the countertop housing shown above, the sump (the long part of the housing) sits on top of the base.

Next, open the filter housing(s).  The long part of the housing, called the sump, screws off of the short part (the cap for undersink units, the base for countertop).  Turn it counterclockwise to remove it. You should have a filter wrench to make the job easy.  Countertop units are often hard to get apart because they aren’t stabilized on a bracket and the wrench doesn’t help.  The best strategy with stubborn countertops is to make opening the housing a two-person job, each person using both hands on one part, the cap or the sump. With multi-cartridge units, it’s a good idea to remember, or even mark for future reference,  the order that the sumps are arranged in so that you can keep the filters in proper order.

Standard undersink housing. The cap is on top and the bottom part, the sump, screws off counterclockwise.

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With filters, you are essentially finished at this point.  With the ledge faucet still open, turn on the water and watch for leaks.  You’ll hear the hissing and gurgling of air being expelled from the unit.  This is normal.  Let the water run from the open faucet for three or four minutes to rinse the new cartridge(s) and allow air to escape while you check for leaks.  Water may appear milky for awhile, even after rinsing.  This is caused by air still trapped in the unit.  It’s nothing to worry about, and it will work its way out eventually.

With RO units, you’re not through yet.  After you’ve turned on the water, listened to some hissing and gurgling, and determined that there are no leaks, open the valve on top of the storage tank and let all the water run from the tank through the faucet. (Since the inlet is on and the unit is making water, when the tank is empty you’ll still have a trickle or a fast drip coming from the faucet.  This is the water the unit is making in real time.) The tank should feel light and empty.  If it doesn’t empty completely, you need to add air to the tank.  (Go here for tank instructions.)  When the tank has emptied, close the faucet and let the unit begin collecting water in the tank.  You can use the water at any time, but you won’t have a lot of water for a few minutes.  If your RO unit has no tank valve and you’ve emptied it previously, you’ll have to let the tank fill completely, then empty it again completely to rinse the final filter.  While it is emptying, remind yourself again to pay a bit more for a unit with a tank valve the next time around.

Greenpeace Accuses Authorities in India of Diverting Water from People to Power Plants

Greenpeace has charged that in drought-plague Maharashtra, the state government diverted water to thermal power plants in scarcity regions.  Water being released from dams, Greenpeace says, is going to power plants when it should be going to people.

The state government said in a government resolution of January of 2013 that water from big, small and medium projects should be reserved only for drinking water, keeping the acute scarcity in mind. Greenpeace believes that this promise is not being carried out.  The area is experiencing the worst drought in 40 years. Many areas report zero storage. 

In the picture above, a government tanker pours 20000 liters of water into the well at Arvi village in Beed district of Maharashtra. As soon as the tanker arrives to empty the water in a well hundreds of villagers rush to fill vessels for household use. 

Energy production is a high consumer of water.   In the power plants of the region, to generate one MW of coal based power, 4,000 to 5,000 liters of water are needed per hour.

Greenpeace has called for a cumulative water impact assessment in the river basins of the state,  a halt to diversion of water in the meantime, and eventually an energy policy which is less water intensive.  Power plant officials point out that they are doing all they can to recycle and conserve water and that power, too, is essential to the region.

Reference source: The Hindu.

Formaldehyde as a Water Contaminant

Although formaldehyde has scary connotations, mainly because of its long-time use as an embalming fluid, it is currently an unregulated substance. Ironically, the most common source of formaldehyde in drinking water is from water treatment.  As is most often the case with chemical contaminants, activated carbon filtration is the best way to remove it.  Here is an in-a-nutshell view of the chemical from the Pure Water Products contaminant list. 

Formaldehyde is a naturally occurring chemical used in the manufacture of other chemicals and in cosmetics, fungicides, fabrics, embalming fluids, wood resins, carpeting, and some cleaning products.

The most common route of human exposure is through inhalation, especially inhalation of cigarette smoke and fuel exhaust,

Formaldehyde is a common ingredient of embalming fluids.

Health Effects of Formaldehyde

Exposure to large amounts of formaldehyde can cause skin irritation. In animal studies, long term exposure to ingested formaldehyde was shown to cause incidences of weight loss and damage to the stomach and digestive system.

The International Agency for Research on Cancer reports that there is “sufficient evidence” that formaldehyde is carcinogenic to humans, but by inhalation rather than ingestion. According to the WHO, drinking-water exposure to formaldehyde is not likely to cause cancer:

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The weight of evidence indicates that formaldehyde is not carcinogenic by the oral route.

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Water Treatment for Formaldehyde

According to the WHO, formaldehyde levels may be reduced with granular activated carbon (GAC) or through changes in disinfection methods.

Sources: EPA, WHO, IARC, Photo: WikiMedia, author: Unknown

 State-of-the-art UV System Will Offer Protection from Cryptosporidium

The Greater Cincinnati Water Works has installed ultraviolet technology in its water treatment facility.

After 10 years and $30 million dollars, the new UV technology process puts Cincinnati on par with some of the top water systems in the country.  The UV lights, which are housed inside massive pipes, will disinfect 40 million gallons of water a day.

Eight Calgon Carbon Sentinel® 48” Chevron UV reactors will have the capacity to treat up to 240 million gallons of drinking water per day.

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 Water is God’s Gift,  but Pumping Costs Money 

 An Editorial from WaterWorld

I was reading an article recently about the flap in Chicago over the city’s plan to phase out free water services to local nonprofits, including religious institutions. An interfaith group held a press conference to oppose the change, claiming that having to pay for water might divert funds from vital social services they provide throughout the city.

I thought it was much ado about nothing, but what caught my eye was a comment from Cardinal Francis George claiming they shouldn’t be charged because water from Lake Michigan was a “gift from God.”

“It wasn’t owned by the city or invented by the city,” he was quoted as saying. Later, he was quoted as jokingly commenting, “We feel sometimes we should charge the city for using our water.”

I really felt a tremendous urge to reach through the Internet and slap said cardinal upside the head. “Your brain was a gift from God. Why not try using it?” I shouted at my computer screen.

As background, Mayor Rahm Emanuel cut the exemption that gave churches free water in December 2011. He initially planned to charge them a growing percentage of the cost of water services that would rise through 2014, when nonprofits would pay up to 80 percent of their water bill. He recently proposed a new system that would charge nonprofits for water based on their assets. Those with net assets under $1 million would be exempt from paying for water, while nonprofits with more than $250 million in assets would pay the full charge. Those in between would pay a discounted rate.

As we all know, providing water service carries a hefty price tag in this time of aging infrastructure and tight city budgets. I found it surprising that a city the size of Chicago would even consider providing free or reduced price water to any organization. I saw one estimate that the program costs the city about $20 million a year.

In a statement, Tom Alexander, the mayor’s deputy communications director, called the asset-based compromise “a fair, reasonable proposal that will allow all nonprofit institutions the chance to continue providing their vital community services while paying their fair share, just as residents do.”

I’m sure many people in the water industry have dealt with dummies who think that water should be free. But as we all know, customers are not paying for water; they are paying for the service to treat and deliver it.

In the small world category, I read the Chicago article as I was researching an article on the value of water to the U.S. economy. You can see the article in this issue. Placing a “value” on water is one thing. Determining a fair price for clean, safe water delivered to a home or business is an entirely separate issue. Communicating that difference to your customers is key.

And when someone says that water should be free, you can tell them it is. “Grab a bucket and run down to the lake. Take as much as you want. I won’t charge you a dime!” 

Source: WaterWorld

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Waterborne microbial disease still the greatest risk to water supplies

By Joseph Cotruvo

Water News in a Nutshell.

In a Nutshell: Since the 1974 implementation of the Clean Water Act the number of waterborne ailments has declined, but the portion of  these attributable to distribution system contamination has increased. Legionella serves as a prime example of  the fact that nature is always evolving and creating microbial hazards. Water treatment to control microorganisms should  be given top priority over ” . . .hypothetical risks of trace chemical contaminants that get a lot of publicity and lead people to spend money on bottled water because they think it is safer.”

Rehabilitation prevents leaks and breaks where inoculation and accumulation occur

Traditionally, most microbial waterborne diseases in the United States are gastrointestinal and short-term, self-resolving infections. They can include bacterial pathogens, enterovirus, rotavirus, norovirus and hepatitis A virus, or protozoa like Cryptosporidium and giardia.

Legionella pneumophila

Although detecting waterborne disease outbreaks is difficult, and numbers are underestimates, reported waterborne disease outbreaks in the United States have declined since implementation of the 1974 Safe Drinking Water Act. The range is from a high of 90 reported outbreaks in 1979-1982 to fewer than 10 in 2002, out of about 60,000 community water systems. In addition, surveillance for outbreaks is today better than in the past, and identification of the causative microbial pathogens has significantly improved.

The reduced outbreak incidence is probably attributable to EPA requirements for microbial quality monitoring and increased water treatment that involves filtration and disinfection of surface water and disinfection of groundwaters. However, while the number of waterborne outbreaks has declined, the portion attributable to distribution system contamination has increased.

In the public eye

Beginning in 2001 Legionaires disease was added to the surveillance and reporting system, and incidences of water-related legionellosis are being reported with some regularity worldwide. Legionellosis is a consequence of inhalation of aerosols contaminated with Legionella pneumophila and perhaps other related species.
Legionaires disease gets its name from a 1976 outbreak among attendees at an American Legion convention in Philadelphia staying at a particular hotel. There were 221 reported cases and 34 deaths from pneumonia. It required about six months of intense microbiological and chemical investigations to identify the causal bacterial agent because there was no known culturing technique available for the then unknown strain of bacteria.

The origin of exposure was blow-down inhaled aerosols from an air-conditioning system. The cases indicated that smokers were at greater risk than non-smokers. Speculation as to origin was rampant, and it even included a supposed “theory” involving a relatively exotic chemical that might have been pyrolyzed while smoking cigarettes. I recall hearing a report from a U.S. Senate committee that undertook its own assessment and announced that supposed chemical cause, shortly before the true microbial agent was identified. Apparently politics and science don’t mix very well.

Retrospective investigations revealed that in fact numerous “legionnaires” cases had occurred previously and had not been identified, and that a milder form of respiratory infection called Pontiac fever was not uncommon. Many outbreaks and deaths have been reported since then, especially in hospitals. The U.S. Centers for Disease Control has estimated up to 18,000 legionellosis deaths in the U.S. each year.

What actually happens

Since 1976 it has been determined that Legionella pneumophila are fairly common soil and water bacteria and pathogenic when inhaled, not from ingestion. They grow under low nutrient warm water conditions at temperatures in the range of 25 C to 50 C. So, they can be present in warm to hot water systems, showerheads, humidifiers, misting and cooling water for air conditioning systems and hot tubs. In distribution systems and plumbing they can colonize biofilms where they may be protected from normal disinfectant residuals.

The at-risk populations are predominantly those who are elderly and also persons with impaired immune systems. Hospital environments have been the source of numerous cases of outbreaks and deaths related to Legionella. However, it is apparent that there are high-risk people in the general population; for them even a typical house or building environment could be a risk, and specific diagnoses and determinations of causal origin will be less likely.

There are water system management techniques for reducing patient risks used by many hospitals. They include monitoring their plumbing systems, additional disinfection and periodic shock disinfection or heating. Chlorine, chlorine dioxide and even peroxides and silver and copper are being used, but with some controversy for the latter two. There are several studies that indicate that systems with chloramine residuals have a much lower risk of a Legionella related outbreak than those with free chlorine residuals. The rationale is that although chloramines are less potent than free chlorine, their lower chemical reactivity allows them to more effectively penetrate biofilms that may harbor the Legionella.

Other recommendations include maintaining hot water systems above 50 C to reduce growth of the microorganisms, but the dilemma is that temperatures in the 55 C to 60 C range introduce a scalding risk, especially for children and seniors.

Moral of story

The law of unanticipated consequences is still functioning. The benefits of modern warm controlled housing environments, air conditioning and indoor hot water plumbing can have downside consequences. Even those beneficial societal technological advances can provide an opportunity for otherwise innocuous microbes to proliferate and cause disease and death.

The moral of the story is that nature is always evolving, and there are perverse unidentified microbes out there that can harm us. Water treatment to control many microorganisms, not just E. coli, is essential, and waterborne microbial disease is still, and always will be, the greatest risk from public drinking water supplies. Aging water distribution systems require aggressive rehabilitation to prevent leaks and breaks where inoculation by microorganisms and accumulation in biofilms can occur. Replacing that aging infrastructure is a much greater national priority than the hypothetical risks of trace chemical contaminants that get a lot of publicity and lead people to spend money on bottled water because they think it is safer.

Source:  Processing.

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