Water You Know?

Week 1

• Q:  What is the approximate pH where phenolphthalein changes between pink and clear?

• A:  A pH of 8.3.  That answer could be handy when checking the reading from your pH meter at times.

Week 2

• Q:  What are the five parameters used to calculate the Langelier Saturation Index or LSI?

• A:  Calcium hardness, total alkalinity, pH, skin temperature, and lastly, total dissolved solids (or conductivity if used to estimate the TDS).

Week 3

• Q:  What is the process called when you mathematically correct for the impacts of changes in feedwater quality, temperature, and pressure on reverse osmosis membrane data as compared to a baseline?

• A:  Normalization.  Don't be comparing apples to oranges.  Normalize your reverse osmosis data so you are comparing oranges to oranges.

Week 4

• Q:  What is the typical percent bed expansion during a water softener backwash?

• A:  Fifty percent.  You have to fluff that bed up to keep it from compacting and to wash out any iron, dirt, and sediment that may collect during the softener's service run.

Week 5

• Q:  What do you call sections in a water system with low or no flow due to system design and/or operation?

• A:  Deadlegs.  Don't let unwanted microbiological activity ruin your day by hiding out in deadlegs.

Week 6

• Q:  Which scale will effervesce when exposed to concentrated hydrochloric acid?  Magnesium Silicate, Calcium Carbonate, or Calcium Phosphate?

• A:  Calcium carbonate as the carbonate portion is converted to carbon dioxide under the acidic conditions.

Week 7

• Q:  What is the proper regeneration sequence of operation for a co-current regenerated sodium zeolite softener system?

• A:  Backwash, then Brine Injection, then Displacement (also known as Slow Rinse), and lastly, Fast Rinse

Week 8

• Q:  At atmospheric pressure, a pound or kilogram of water that is converted to steam will expand by approximately how many times?

• A:  1,600 times.  That is quite the explosive expansion!

Week 9

• Q:  What effect will water temperature have on softener backwash during regeneration?

• A:  Higher backwash flowrates will be required with higher temperatures and lower backwash flowrates for lower temperatures, due to the changes in density and viscosity of the backwash water.  Too high a backwash during colder months could lead to resin being washed down the drain.  Check your resin manufacturer's specifications for proper seasonal flowrates.

Week 10

• Q:  What is the conversion between parts-per-million and milligrams per Liter?

• A:  The answer is One.  For dilute aqueous solutions like the waters we deal with in industrial water treatment, one part-per-million equals one milligram per Liter.  

Week 11

• Q:  What is the molar mass of calcium carbonate?

• A:  It is 100 grams per mole. We get this by adding the atomic weight of Calcium, which is 40, Carbon, which is 12, and THREE oxygen atoms, which is 16 each or 48 combined.  Adding all these together gives the sum of 100 grams per mole for Calcium Carbonate.

Week 12

• Q:  What is a plastic or rubber device that seals the outside of a reverse osmosis membrane against the inside wall of the pressure vessel to prevent feedwater from bypassing around the membrane element?

• A:  It is a brine seal.  The design of the brine seal may dictate both its orientation and the direction the membrane should be loaded.

Week 13

• Q:  What do you call the attraction of water molecules to each other that gives water its unique properties, such as a high surface tension, high boiling point, and ability to dissolve many substances?

• A:  It is called Hydrogen bonding.  You knew I would throw this into the mix eventually, because, after all, hydrogen bonding IS my favorite type of chemical bonding.

Week 14

• Q:  What is the process called to evaluate the performance and efficiency of a water softener by taking regeneration water samples, measuring their salinity, and interpreting their results?

• A:  It is called an elution study.  When a water softener is not behaving as expected, performing an elution study is often a relatively easy step to take to help diagnose the problem.

Week 15

• Q:  What scaling index was developed in 1936 to predict the scaling potential of calcium carbonate in drinking water systems?

• A:  It is the Langelier Saturation Index or LSI.  Yes, it was originally designed for more stable water sources and yes, it ONLY tells us about the scaling potential of calcium carbonate, but, for the lack of anything better, it has since been extended to be used in industrial water treatment applications such as cooling towers, reverse osmosis, etc.  Other stability indexes include the Ryznar Stability Index and the Practical Scaling Index.  Advanced water modeling software, such as WaterCycle, is also available.

Week 16

• Q:  Does silica solubility typically decrease or increase with rising temperature?

• A:  It will typically increase.  When cleaning an RO, for example, higher temperatures can increase the solubility of silica deposits, making them easier to dissolve and remove from the membrane surface.  There are always exceptions, though.

Week 17

• Q:  What is the phenomenon called where calcium and magnesium are LESS soluble as the temperature RISES?

• A:  It is called retrograde solubility.  The LAST place we want insulating scale to form is on the heat exchange surface, but due to calcium and magnesium's retrograde solubility, this is often the FIRST place they form scale.  But, hey, it keeps life interesting, right?

Week 18

• Q:  What do you call the large-diameter tube in firetube boilers where the combustion of fuel takes place?

• A:  It is called a Morrison tube.  It may even be corrugated to enhance strength, heat transfer area, and promote turbulence in the combustion gasses.

Week 19

• Q:  When measuring a volume of water in a graduated cylinder, what do you call the curve of the liquid when it touches the side of the cylinder?

• A:  It is called a meniscus.  For liquids like water, it forms a concave meniscus, and we read the volume at the bottom of the curve.

Week 20

• Q:  What do you call the device commonly used to measure the percentage of salt in a softener brine solution?

• A:   It is called a salometer or, simply, a hydrometer.  It's a useful, easy troubleshooting tool to have handy when monitoring and troubleshooting brine-regenerated water softeners.  It is used to not only determine the percent saturation of the salt solution in the brine tank, but also used to monitor the diluted salt concentration exiting the water softener during the brine-draw and slow-rinse displacement steps to form an elution curve.

Week 21

• Q:  What field test is used to measure how likely a water source is to foul reverse osmosis membranes due to suspended solids?

• A:  It is a Silt Density Index or SDI test.  It measures the rate at which a filter is plugged by water under constant pressure.  The lower the SDI, the less fouling the water is expected to be to an RO membrane.  A common goal is an SDI less than 3 with a value between 3-5 requiring more frequent cleaning.  Beyond this, upstream filtration to remove submicron particles is typically required.  Membrane manufacturers and system designers may have slightly different SDI ranges.

Week 22

• Q:  What do you call the enclosed space between the drift eliminators and the fan in an induced-draft tower?

• A:  It is called the plenum.  The size of the plenum can be significantly different between a crossflow and counterflow induced-draft cooling tower, which can impact the ease of maintenance.

Week 23

• Q:  Are conductivity and Total Dissolved Solids the same thing?

• A:  No, they are not the same thing, but they can be related.  Conductivity measures a water's ability to conduct current.  Total Dissolved Solids or TDS is the concentration of dissolved solids in a water solution.  Conductivity can be quickly measured with a meter or probe.  Total Dissolved Solids involves evaporating a volume of water to dryness and weighing the remaining solids.  Typically, though, the higher the dissolved solids, the higher the conductivity, and vice versa.  A correlation between the two can often be found but should be verified on a regular basis.  A common assumption used is total dissolved solids is 65-75% of the conductivity, depending upon the ions present.

Week 24

• Q:  Which water analysis measures the concentration of hydrogen ions in water?

• A:  The answer is pH.  Mathematically, it is the negative logarithm of the concentration of hydrogen ions.  In practice, we look at pH as how acidic or basic a water is.  It has a range between 0 and 14 with 7 being neutral.  Below 7 is more acidic and above 7 is more basic.

Week 25

• Q:  What is the breakpoint chlorination ratio of chlorine to ammonia required to reach a true free chlorine residual?

• A:  While the stoichiometric answer is 7.6 to 1 of chlorine as Cl2 to ammonia as nitrogen, competing reactions may make the actual ratio 8 to 1 or even 10 to 1 or above.  This is why it is important to develop a breakpoint chlorination curve at varying dosages to confirm.

Week 26

• Q:  What is defined as the acid-absorbing property of water?

• A:  The answer is alkalinity.  We commonly think of carbonate, bicarbonate, and hydroxide as being primary components of alkalinity; however, other ions, such as phosphates, can also contribute.

Week 27

• Q:  How many ppm of sodium sulfite does it take to react with one ppm of oxygen?

• A:  The theoretical ratio is 7.88 ppm of chemically pure sodium sulfite to react with 1 ppm of dissolved oxygen.  In practice, approximately 10 ppm of sodium sulfite are required for each ppm of oxygen. This accounts for the use of technical grade sodium sulfite, as well as handling and blowdown losses encountered during plant operation.  Note that sodium bisulfite and sodium metabisulfite have different ratios.

Week 28

• Q:  What do we call the ratio between the amount of dissolved solids in a system water and the amount of dissolved solids in that system's makeup water?

• A:  The answer is cycles of concentration.  You get extra brownie points if you said "Concentration Ratio,"  which is Trace's preferred phrase.

Week 29

• Q:  What are the two primary ways heat is rejected by a cooling tower?

• A:  The answer is evaporation and sensible heat rejection.  The ratio between these two will vary depending upon local weather conditions and seasons.

Week 30

• Q:  If you place a small amount of concentrated hydrochloric acid on a deposit sample and it bubbles, what is this likely to indicate?

• A:  It probably indicates the presence of carbonate salts.  Oftentimes, it is calcium carbonate.  Knowing your systems and water quality plus this quick acid-bubble test can be a real troubleshooting asset in the field.

Week 31

• Q:  Why is barium chloride used in the standard Hydroxide Alkalinity test?

• A:  Barium chloride is used to precipitate any carbonates so the titration with acid will hopefully detect only the alkalinity associated with hydroxide alkalinity.

Week 32

• Q:  What do we call the formation and subsequent collapse of vapor-filled bubbles in water due to rapid pressure changes?

• A:   We call this cavitation.  As these bubbles collapse, they can generate intense shockwaves which can cause damage to equipment surfaces, such as pump impellers.

Week 33

• Q:  Despite all the training, engineering controls, policies, regulations, laws, and direction, at the end of the day, who is most responsible for your personal safety?

• A:   You.  Yes, there are and should be many layers to keep you safe in your job, but it is up to you to follow them and use common sense to keep YOU safe.  Your family, friends, and colleagues are counting on you.

Week 34

• Q:  What is the mass balance around a cooling tower?

• A:  A mass balance simply means that what goes in must come out.  Starting with what goes into a cooling tower includes the makeup water.  Is there a secondary makeup water source as well?  Is there any process inleakage anywhere?  Is rain a periodic makeup source?  Moving on to what leaves a cooling tower water system, there is evaporation and blowdown.  There may be unintentional water losses as well, including overflow, windage, drift, process leaks, pump seal leaks, and basin leaks.  Knowing all the ways water can get into and out of a cooling tower system can be important to know when you are troubleshooting.

Week 35

• Q:  What is it called when a valve is closed at the end of a pipeline system causing a pressure wave to propagate in the pipe and a loud banging sound?

• A:  Water Hammer.  It is also called hydraulic shock or fluid shock.  It can not only be noisy and cause vibration but can also lead to pipe rupture and collapse.

Week 36

• Q:  Does Hydroxide Alkalinity in a steam boiler water ALWAYS equal 2P-M?

• A:  The answer is NO, it is not ALWAYS true, which may surprise some.  I'll grant you that in most low to medium pressure boiler water applications, the 2P-M relationship probably does hold true.  When there are interferences to the P and M alkalinity tests, however, this equation does NOT hold true.  Possible interferences include polymers, phosphate, and even neutralizing amines which can increase the acid absorbing ability of water.  Also, the 2P-M relationship only holds true when the P-Alkalinity is greater then 1/2 of the M-Alkalinity.  You may be well served to run the barium chloride test for hydroxide alkalinity to help confirm the mathematical equation holds true for your system.

Week 37

• • Q:  What are some reasons for softener resin beads to crack?

  • A:  Possible reasons include osmotic shock, oxidation, thermal shock, degradation, high pressure drops, water hammer, and age.  Resin type may play a role as well since some may be more susceptible to cracking than others.

Week 38

• Q:  Back in the day, what was the treatment used for corrosion inhibition in cooling water systems that was banned around 1985 in the United States from widespread use due to its toxicological impact?

• A:  The answer is chromate.  While it was an excellent corrosion inhibitor and its yellow color often made it easy to monitor, chromate's ban helped push the industrial water treatment industry to develop many of the treatment chemistries we have today.

Week 39

• Q:  What type of resin is primarily used in a sodium zeolite water softener?

• A:  The type of resin primarily used in sodium zeolite water softeners is a Strong Acid Cation resin…specifically in its sodium form.

Week 40

• Q:  What do you call the waste stream coming out of a reverse osmosis unit?

• A:  It is commonly called "concentrate" or "reject," but also referred to as "brine."  Of course, one person's waste stream is another person's treasure, with alternative uses sometimes found for this water.

Week 41

• Q:  

• A:  

Week 42

• Q:  

• A:  

Week 43

• Q:  

• A:  

Week 44

• • Q:  

  • A:  

Week 45

• • Q:  

  • A:  

Week 46

• • Q:  

  • A:  

Week 47

• Q:  

• A:  

Week 48

• Q:  

• A:  

Week 49

• Q:  

• A:  

Week 50

• Q:  

• A:  

Week 51

• Q:  

• A:  

Week 52

• Q:  

• A: