Mike-O-Pedia FAQs for Water Treatment Professionals

The purpose of the “Mike-O-Pedia” is to share knowledge with our peers.  We will be posting on a regular basis and look forward to answering questions or discussing comments and applications with our dealer customer base.

Topic: Water Softeners

Which Salt to Do We Use?

Scale Removal

Removing Iron with a Water Softener

Water Hardness & Low pH

Should I use an upper screen?

What type of resin do I use in a softener?

How long does softener resin last?

Should I install a water softener to remove lead?


Topic: Using a MAV (Motorized Alternating Valve) on a Twin, Tri or Quad Softener or Filter

Using two filter or softener tanks instead of a single tank, helps avoid failed installations.  This happens when a single tank bed can no longer function because the contaminant has overwhelmed the bed and fouled the media. This can result in excessive pressure drop, and cloudy, dirty water coming out of the tap. 

This problem occurs because the backwash or regenerant water is untreated raw water. The media is getting fouled at the bottom and top of the single tank.  Twin tank systems solve the problem.  When regeneration or backwash is called for, a portion of the water is drawn from the clean secondary tank.

This is accomplished with the use of a Clack MAV – Motorized Alternating Valve. MAV Specification

 Applications/Options

Topic: Understanding High Efficiency Water Softeners

How efficient are the softeners you’re selling?  Why does it matter?  Highly efficient softeners use less salt.  Consumers will see salt savings and fewer backbreaking trips from the store to the brine tank. Environmentally there is less chloride discharge to the septic system or municipal waste system.

Typically, 1 cf of resin yields 30,000-34,000 grains if you regenerate with 15 pounds. As regulators and consumers have become more environmentally conscious demand for softeners which use less salt has increased. Highly efficient (HE) softener design is proprietary to the OEM. Through the use of specially designed tanks, distributors and valves, these softeners get 4,300 grains of capacity with just 1 pound of salt.

The easiest way to explain this to think about the way a sponge is used.  A sponge effectively cleans a surface when it is damp.  If you use a sponge which is soaked with water the cleaning process is messy.  The excess water will come out of the sponge onto the surface.  The result would be a very wet surface which is only partially clean.

You don’t need 15 pounds of salt to effectively regenerate the HE softener.  There are diminishing returns.  Using a 1 cubic foot softener here are the numbers:

As you see, you get more total grains when using 15 pounds.  The problem with that 15 pounds is that you go through a bag of salt more quickly than if you use 4.5 pounds.  A 50-pound bag of salt yields 3.3 regenerations when using 15 pounds per regeneration.  Using that same 50-pound bag at 4.5-pound regenerations the yield is 11 regenerations.

⚠️Using less than 4.5 pounds of salt is not recommended.  At lower rates the resin beads will not be sufficiently regenerated and shorter run lengths will result.

Additional savings with high efficient softeners include:

These systems have been designed and manufactured by OEM’s who sell entire systems and not just the components.  There are OEM’s who sell HE softeners to independent dealers.

Can a High Efficiency softener be used if there is iron and manganese in the water?

In the northeastern U.S. we use water softeners to remove these contaminants.  The species of iron and manganese are easily removed because there is low TDS and not much competition of other cations.  (It’s mostly a dissolved, low pH water.)  These softeners are fondly called “salt hogs” because you need to regenerate with a lot of salt to drive the iron and manganese off of the resin.

A HE softener can be tweaked to increase the salt dosage to compensate for the iron and manganese.  Rather than using the full 15 pounds of salt you can cut back to 10 pounds of salt.


Topic: Distributions Systems – Tank Internals

Riser Tube, Standpipe, Distributor Tube

Question: When should a gravel sub-fill be used in a mineral tank?

When to Use Gravel Sub-Fill

Equipment
Yes/NoComment
Carbon Filters - Backwashable TypeYesIf recycling carbon, separation of gravel from carbon is required.
Carbon Filters VOC RemovalNoBackwashing a carbon filter used for VOC removal will upset the mass transfer zone and may result in leakage of the contaminants.
Acid NeutralizersYesUpflow & Downflow systems
Softening - UpflowNoN/A
Softening - DownflowYes Creates a better flow pattern.

Hub & Lateral Tank Internals

Urbans Aqua offers standard and custom distribution systems.


Topic: Activated Carbon

GAC Specifications – What do they measure?

Iodine Number

How closely in size is the contaminant to a molecule of iodine?   The higher the iodine number the better the removal of molecules which closely resemble iodine.  Iodine is a small molecule therefore it measures ability to adsorb lower molecular weight smaller substances.

Molasses Number

Molasses number Is a measurement of the degree of decolorization of a standard molasses solution.  It is a relative guideline for measuring the capacity of the carbon to remove color molecules.

Abrasion Number

Demonstrates the carbons ability to withstand degradation during handling – before and after it is placed into service.  Lower abrasion numbers result in more dust and fines.

Density, Backwashed & Drained (BWD)

This is the number of pounds required to fill a cubic foot of volume capacity.  Caution– The density of activated carbon types varies.

TCN – Trace Capacity Number

The Trace Capacity Number measures the number of high energy pores in an activated carbon product. These high energy pores are required to remove difficult to adsorb contaminants, such as MTBE. The theory behind the test is similar to the Iodine number, where the iodine number reports the mg Iodine per gram of carbon in a standard iodine solution. Since iodine is so strongly adsorbed, it is essentially fills all of the adsorption pores (high energy and low energy). The TCN number uses a more difficult to adsorb species and reports the mg loaded per gram of carbon. A higher TCN number on a carbon would indicate a higher number of high energy pores, which would suggest better loading in an application with difficult to remove contaminants.

Ash

The ash content of a carbon can be defined as the noncombustible mineral matter that is contained in activated carbon. It is the residue that remains after the combustion of a carbonaceous material and is normally defined on a weight basis. The ash content is dictated by the raw material used to manufacture an activated carbon product and is why a high purity raw material is necessary to produce a high purity activated carbon product. There are also additional post-processing steps, such as acid washing, to reduce the amount of ash content in an activated carbon product.

Water Soluble Ash

Ash measures the level of purity.  It is the inorganic residue left after the heating process.  It consists of silica, calcium, alumina, iron, magnesium with a potential for arsenic.  Carbon may be acid washed or water rinsed to reduce ash content. Water extractable ash has the highest impact on the product quality as it affects the effluent.

Can Activated Carbon be regenerated?

Activated carbon cannot be regenerated like ion exchange resin.  Activated carbon can be reactivated by carbon manufacturers.  The reactivation process is similar to the original activation process. The resulting product is distributed for waste water applications.  Municipalities contract to reactivate segregated lots for re-use.

It is possible to reactivate activated carbon with steam.  Beverage manufacturers have large carbon filters which have steam injection.  The heat from the steam will push off the more weakly held contaminants freeing up pores for continued use.  The steam also sanitizes the carbon bed.  Steam reactivation will restore the life of the carbon bed but eventually the cost outweighs the benefit and a new carbon bed must be installed.

Which type of carbon do I use?

How to remove PFOA & PFOS from drinking water using Calgon Carbon.

What is Enhanced Coconut Carbon?

Chloramine Removal with Activated Carbon

To meet tougher THM (trihalomethane) standards municipalities are moving to chloramine disinfection.

Drill down and it’s a little more complicated:

Example 1: Homeowner who wants to remove all traces of chloramine (or chlorine) and the THMs from their city water. No problem? Think again.

Because the chloramine reaction is catalytic in nature, activated carbons with enhanced catalytic activity are more efficient, last longer and enable you to use smaller equipment.

Example 2: The pH of the water we were treating was not between 6 and 9. It was around 4. Even though the water was being treated with carbon there was residual chlorine which set off alarms. If the pH was high, no problem. Of course we contacted the experts at Calgon for help. Their first question – Were we dealing with chlorine or chloramine?

Long story short – The municipal water being disinfected with chloramine. At the lower pH the species is trichloramine, or nitrogen trichloride.

With activated carbon the catalytic reaction with chloramine is opposite of chlorine.

The trichloramine was sneaking through the carbon because the pH was low. The solution – either raise the pH or use a catalytically enhanced coal base carbon such as Centaur® to resolve.


Topic: Arsenic Removal

Arsenic is a grey, semi-metal element.  Arsenic enters ground water from both natural sources and human activity. Contamination can sometimes be traced to deep-water brines produced from gas and oil well drilling. It is also be found in wood preservatives and may be a byproduct of herbicide production.

Health Effects

Arsenic has a primary drinking standard because it is known to have health effects when present in drinking water.  Skin lesions, circulatory problems and nervous disorders can occur.  Prolonged exposure may result in skin, bladder, lung and prostate cancer.  For this reason, the EPA has set the MCL to 0.01 mg/L (micrograms per liter).   Arsenic removal from wells

Arsenic Reduction/Removal from Water

Arsenic is one of the hardest ions to remove from water.  It usually occurs in water as either arsenate (AsV) or arsenite (AsIII).  Test results report the total arsenic concentration including arsenic as arsenate and arsenic as arsenite. Aresenite is a greater health concern and more difficult to remove.  For this reason, most treatment solutions start by adding an oxidant to the water to convert all arsenic to the arsenate form.  Oxidation can be accomplished through the addition of chlorine, ozone or greensand.  Note: Chloraminated water utilizing only monochloramine (NH2Cl) will not completely oxidize AsIII to AsV).

Heating or boiling water will not remove arsenic from water, it may increase the concentration as the water is evaporated off.

To determine the best removal treatment the water must first be tested by a certified lab.

Removal methods include Activated Alumina, Manganese Greensand Filtration, Distillation, and Reverse Osmosis.  Urbans Aqua offers specialty products – Purolite’s FerrIX™ A33E and Graver’s Metsorb®.  All products used for arsenic removal should be NSF or WQA Gold Seal Certified.

Before embarking on a treatment regiment, a full water analysis is necessary.  Since Arsenic is anionic, you must test for competing anions.  Both Purolite and Graver have a water profile work sheet that must be filled out, so they can better estimate bed life.  Contact Urbans Aqua for equipment system design.

Download Documents:

MetSorb HMRG Media Applications GuidePOE

MetSorb(R) HMRG datasheet

MetsorbBrochure

FerrIX A33E -Engineering Bulletin-0425 2016

FerrIXA33E Product Data Sheet

Arsenic Removal Products – Pros & Cons

Activated Alumina 

Pros

Cons

Distillation

Pros

Cons

Ion Exchange Anion SBA I & II

Pros

Cons

Manganese Greensand

ProsPFC-Webinar-Presentation-1-30-17Jacobi CX-MCA

Cons

Reverse Osmosis

Pros

Cons

FerrIX A33E

Pros

Cons

Metsorb®

Pros

Cons


Common Residential Installation Problems & Challenges

Common Commercial/Industrial Installation Problems & Challenges

Delaware Water Softener Waiver

Backwash Volume Data Chart_3


Topic: Resins – Mixing Cation and Anion Resin in One Tank – (NOT MIXED BED RESIN)

The resins we are discussing here are as follows:

When these resins are in separate tanks the cation always goes ahead of the anion tank. As a result, the hardness minerals are removed before the water goes through the anion resin.

A potential problem may occur as a result if the water hardness is above 6-8 grains hardness.

How to avoid the problem.

How to repair.