CT Basement Systems Radon Blog by Matthew A. Bednarz V.P.

URANIUM IN WELL WATER

Posted by Matthew Bednarz on Fri, Oct, 06, 2017 @ 13:10 PM

uranium in well water

Uranium in well water has received much attention recently as a result of the State of CT recommending all private water well owners to test their water for uranium and arsenic http://1.usa.gov/WBDYmi (in addition to the common general water quality parameters).  Uranium (U) is naturally occurring in the earth's crust, and can dissolve into water if that water source is exposed to uranium bearing rock strata.  There is a significantly greater probability of elevated uranium in well water rather than in surface water supplies.

uranium concentrations[1]

High levels of uranium in well water may increase the risk of cancer and kidney damage.  The EPA has established 30 ppb as a maximum contaminant level (MCL) with a maximum contaminant level goal (MCLG) of zero.  The MCL was established on the basis of the heavy metal toxicity of uranium - not radioactivity.  It is this toxicity that is the primary health concern - not radioactivity when assessing health concerns over the ingestion of uranium in well water.  Uranium decreases the kidneys' ability to remove impurities from blood.  This condition is reversible if uranium consumption is eliminated.  However; it is the concern over radioactivity that must be contemplated when implementing a removal strategy. 

uranium

 Treatment systems that absorb or collect uranium with no backwash or regenerating capability will eventually reach a saturation point for radioactivity requiring special permitting for disposal of spent filter media.  Therefore, the most prudent approach for Point of Entry (POE) uranium in water removal is anion exchange.

While appearing quite similar to a water softener, (the outward appearance of both systems are identical) the anion resin functions differently from negatively charged cation (softening) resin.  Rather than removing positively charged ions out of the water, as is the case with water softener (cation) resin, anion resins have a positive charge and remove negatively charged ions (such as uranium and arsenic).  When an anion system regenerates, it uses the chloride portion of sodium chloride rather than the sodium portion that the cation resin does. 

The State of CT views anion exchange systems as a viable treatment option provided these systems discharge any water from the regeneration process into a dedicated sub surface drainage system (drywell).  Anion exchange is the most viable cost effective, whole house treatment solution for uranium in well water removal.

sub surface drainage 2017.jpg

A combination unit (referred to as a "mixed bed" softener) can also be installed if there is both hardness & uranium present in the same water supply.  This is an especially useful tool when floor space is at a premium.  The cation & anion resins are simply mixed within the same vessel.  This is a practical approach when applied to water with hardness levels up to 7 gpg.  

water softener cut away view resized 600

Reverse osmosis (RO) is the preferred point of use (POU) treatment to remove uranium in well water.  RO is a process where water is squeezed under pressure, through a semi - permeable membrane, filtering out the majority of dissolved solids, leaving just water that is free of dissolved solids for consumption. 

point of use reverse osmosis

The disadvantages to this option are; limited / slow production capacities, and the issue of having to draw water from a specific tap to get water that is treated...all other points of use in the home are not treated.  While installing separate POU RO systems can be a solution...it isn't practicle...and is oftentimes not feasible to accomplish.

Whole house reverse osmosis (point of entry POE) is an alternative to anion exchange and POU RO, but it can be cost prohibitive for many homeowners from both an install and maintenance perspective.  In order to have enough available water for demand, a large storage reservoir with repressurization is required.  Whole house reverse osmosis systems also "waste" large volumes of water to drain while processing treated water.

 

whole house reverse osmosis

Click Here to contact us for  Uranium Testing Today!

uranium in well water removal specialist

   

Topics: uranium in well water, water softener, reverse osmosis, mixed bed water softener, anion exchange

URANIUM IN WELL WATER

Posted by Matthew Bednarz on Fri, Jun, 12, 2015 @ 09:06 AM

uranium in well water

Uranium in well water has received much attention recently as a result of the State of CT recommending all private water well owners to test their water for uranium and arsenic http://1.usa.gov/WBDYmi (in addition to the common general water quality parameters).  Uranium (U) is naturally occurring in the earth's crust, and can dissolve into water if that water source is exposed to uranium bearing rock strata.  There is a significantly greater probability of elevated uranium in well water rather than in surface water supplies.

uranium concentrations[1]

High levels of uranium in well water may increase the risk of cancer and kidney damage.  The EPA has established 30 ppb as a maximum contaminant level (MCL) with a maximum contaminant level goal (MCLG) of zero.  The MCL was established on the basis of the heavy metal toxicity of uranium - not radioactivity.  It is this toxicity that is the primary health concern - not radioactivity when assessing health concerns over the ingestion of uranium in well water.  Uranium decreases the kidneys' ability to remove impurities from blood.  This condition is reversible if uranium consumption is eliminated.  However; it is the concern over radioactivity that must be contemplated when implementing a removal strategy. 

uranium

 Treatment systems that absorb or collect uranium with no backwash or regenerating capability will eventually reach a saturation point for radioactivity requiring special permitting for disposal of spent filter media.  Therefore, the most prudent approach for Point of Entry (POE) uranium in water removal is anion exchange.

While appearing quite similar to a water softener, (the outward appearance of both systems are identical) the anion resin functions differently from negatively charged cation (softening) resin.  Rather than removing positively charged ions out of the water, as is the case with water softener (cation) resin, anion resins have a positive charge and remove negatively charged ions (such as uranium and arsenic).  When an anion system regenerates, it uses the chloride portion of sodium chloride rather than the sodium portion that the cation resin does. 

The State of CT views anion exchange systems as a viable treatment option provided these systems discharge any water from the regeneration process into a dedicated sub surface drainage system (drywell).  Anion exchange is the most viable cost effective, whole house treatment solution for uranium in well water removal.

A combination unit (referred to as a "mixed bed" softener) can also be installed if there is both hardness & uranium present in the same water supply.  This is an especially useful tool when floor space is at a premium.  The cation & anion resins are simply mixed within the same vessel.  This is a practical approach when applied to water with hardness levels up to 7 gpg.  

water softener cut away view resized 600

Reverse osmosis (RO) is the preferred point of use (POU) treatment to remove uranium in well water.  RO is a process where water is squeezed under pressure, through a semi - permeable membrane, filtering out the majority of dissolved solids, leaving just water that is free of dissolved solids for consumption. 

point of use reverse osmosis

The disadvantages to this option are; limited / slow production capacities, and the issue of having to draw water from a specific tap to get water that is treated...all other points of use in the home are not treated.  While installing separate POU RO systems can be a solution...it isn't practicle...and is oftentimes not feasible to accomplish.

Whole house reverse osmosis (point of entry POE) is an alternative to anion exchange and POU RO, but it can be cost prohibitive for many homeowners from both an install and maintenance perspective.  In order to have enough available water for demand, a large storage reservoir with repressurization is required.  Whole house reverse osmosis systems also "waste" large volumes of water to drain while processing treated water.

 

whole house reverse osmosis

Click Here to contact us for  Uranium Testing Today!

uranium in well water removal specialist

   

Topics: uranium in well water, water softener, reverse osmosis, mixed bed water softener, anion exchange

REVERSE OSMOSIS WATER TREATMENT

Posted by Matthew Bednarz on Fri, Dec, 07, 2012 @ 14:12 PM

reverse osmosis water treatment

                                             REVERSE OSMOSIS

It can be said that Reverse Osmosis is the pinnacle of water filtration.  The phenomenom of osmosis was first recognized by a French scientist in the mid 1700's when he noticed that water spontaneously passed through a pig bladder into a solution of alcohol. But it wasn't until the 1950's when viable membranes were able to be manufactured in the US, that reverse osmosis technology became recognized as a reliable treatment solution for certain water quality issues.

Osmosis occurs when a liquid (for our purposes - water) low in total dissolved solid(TDS) content passes through a semi-permeable membrane or barrier, and dilutes a water source that has a higher TDS content.  The passage of the water through the membrane generates a "head difference" between the two water sources.  This head difference is a measure of the concentration difference of the two water supplies and is referred to as: osmotic pressure difference.

OSMOSIS PROCESS resized 600 

When pressure is applied to the water source containing the higher dissolved solid content - that exceeds the osmotic pressure - the flow of water is reversed through the membrane...hence; "Reverse Osmosis".

C  Documents and Settings ctbs03 My Documents My Pictures REV OSMOSIS

The water that ends up being the finished product from the reverse osmosis process is known as "permeate".  Having been squeezed through a semi - permeable membrane; the permeate is low - if not almost absent of TDS.  Pure water doesn't truly exist in nature...permeate from an efficient RO system is about as close as you can get to "pure" in practical terms.  To put in perspective the level of processing that occurs; the average human hair is 75 microns in diameter.  Reverse osmosis can filter the water down to .0001 microns!  This is truly filtration at the molecular level.  In fact, the degree of filtration is such, that bacteria and viruses can be removed.  However; feed water to a reverse osmosis system should be bacteria free, otherwise, the membrane will get fouled and can become "ground zero" for a contamination issue of a home's plumbing system. 

This level of processing is not without drawbacks.  Because the water is so free of dissolved solids, some consumers think RO water tastes too "flat" or has no character - there are remedies available for this scenario, and it is subjective to the individual.  It also takes time for a reverse osmosis system to "make" or process useable water.  Remembering that water is squeezed through a semi - permeable membrane, producing enough water for practical use doesn't happen quickly.  Depending on certain conditions, it can take two - three gallons of water running to drain for every one gallon of permeate produced.  Depending on job site conditions, waste water reclamation may be an option.

The most common residential application of reverse osmosis technology is in the Point of Use (POU) format.  This typically involves a compact unit mounted under a kitchen sink with a faucet installed specifically to dispense the permeate.  Water dispensers and ice makers in refrigerators can often be hooked up as well.

POU under counter RO system

Depending on the nature of the contaminant, layout of the home, desired end result of the consumer and budget; whole house reverse osmosis or point of entry (POE) reverse osmosis, is an alternative option.

whole house reverse osmosis

A consideration of POE reverse osmosis systems is corrosion.  Permeate is low if not free in TDS content.  Water - nature's solvent - becomes more "aggressive" or corrosive as the TDS content is reduced.  Feeding permeate through a copper plumbing system can invite corrosion of pipes and fittings while leaving stains in sinks, toilets, and showers.  Appropriate measures should be taken to protect metal plumbing systems.

While the reverse osmosis process has a wide array of contaminants it can remove, water must be pre - treated to remove excessive amounts of iron, manganese, and hardness so the membrane doesn't become clogged and fail prematurely.  This is especially important when the feed water is from a private water well.  If the feed water is municipally supplied, a chlorine resistant membrane (celluose triacetate) or chlorine removal pre treatment stage must be implemented because chlorine will destroy a thin film composite membrane.

Reverse osmosis is a highly effective treatment process.  It should be placed downstream from all other treatment stages and thought of as a "polisher" for the potable water.  RO should not be utilized as the primary treatment for aesthetic water issues as these contaminants will quickly foul the system.  The two most common applications for private water wells in CT are for lead and sodium removal.  As is the case with any water treatment device, proper maintenance schedules should be observed to ensure your reverse osmosis system is delivering the highest quality water possible.

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Topics: bacteria, RO, reverse osmosis, total dissolved solids, permeate, TDS