pH, Alkalinity, and Hardness for your Water Treatment or Distribution Exam

mmm hi I'm ty Whitman what I want to do for you today is talk about some subjects that can be extremely difficult for a lot of people learn namely the subjects of pH alkalinity and hardness we're also going to kind of talk about calcium carbonate saturation we're going to talk about measurement of calcium carbonate saturation we're going to talk about acids and bases and we're going to talk about how all of this ties in together now it's really easy to sit down and learn a definition for pH or a definition for alkalinity but to try to understand pH try to understand how it relates with alkalinity how to understand how alkalinity relates with hardness can be extremely extremely confusing I'm not going to lie to you it was very difficult for me back when I was learning this stuff to understand it everything that seemed like it's out there's written from this advanced chemistry PhD point of view and it was just nuts to try to muddle through to make sense of everything to grab that big picture what I'm going to try to do for you today is I'm going to try to break these down into very simple terms and put it into an easy little 10 to 15 minute package they'll save you all that time that I went through it's not easy for you to learn I'm going to make it easy and I'm going to be totally honest with you this video isn't easy for me to do this is I take 463 haha even though I know this subject but I know it's essential and I know it's necessary for me to do because I know I can save you a lot hassle that I went through so let's go ahead and get started let's talk about first off other than your water treatment exam why should we care about this stuff well pH and alkalinity are two basic tests that you can perform to test for the health of water and they affect many things including water hardness and including corrosive 'ti abrupt changes can also be signs of water quality issues such as an intra Cajun now an intrical what you have is a nitrite and nitrate oxidizing bacteria that consume the alkalinity in that water in the process of consuming that alkalinity they create acid and acids can drop the pH noticeably so just for an example if you have a sudden drop in alkalinity a seven drop in pH it can be signs you have mystification going on in your system we're going to start by defining pH and then we're going to jump to the definition of alkalinity what pH is is it's a measure of an acidic or basic nature of a liquid a measure of the acidic or basic nature of a liquid and it's quantified on a scale that goes from zero to fourteen with zero being most acidic 14 being most basic and seven being neutral right in the middle right there a low pH water is undesirable because having that acid in the water can cause corrosion in the mains it can cause well the corrosion that mains can cause holes in the mains it can cause damage it can cause a lot of money and repairs and damage your holes and main leaks and things like that but over and above that and acidic water can cause a leaching of harmful things that like lead copper out of pipes and they can leach that into the system and into the water and they get into us and they're bad so there's a lot of reasons we don't want acidic water water is too basic on the other hand has other things that can go wrong with it like deposition of scale and so forth now I want to take it a nether step farther and talk about this symbol right here okay we get it it's a measure of an acidic or basic nature of water zeros acid 14 is basic what does that mean what does that mean what I just said well pH and the reason why it's written kind of funny like that is because it actually stands for the power of hydrogen the element hydrogen let's take that and break that down a second and then we'll come back to that so we have water right here h2o and certain small amounts that water can break apart into the hydrogen ion it can also break apart into the hydroxide ion the hydrogen ion is acidic the hydroxide ion is basic so pH the power of hydrogen basically meant the amount of hydrogen ions that are floating around in that water so the more hydrogen ions the more acidic a solution is the less hydrogen ions the more basic a solution is let's talk about these acids and bases for a second just to kind of recap that a little bit and add to it a little bit acids our solutions to supply hydrogen atoms I'll give you an example hydrochloric acid HCl it can break apart into that hydrogen ion and the chlorine ion bases on the other hand are solutions that provide hydroxide ions and give you another example that sodium hydroxide can break a partner to the sodium ion and the hydroxide ion so if you ask yourself well what's water is it an acid or a base well distilled water is neutral because the hydrogen ion is counteracted by the hydroxide ion and it's exactly neutral so distilled water would have a pH of 7 which is neutral natural source waters are about six and a half to eight and a half because bases can be picked up as water runs through a you know line for example as water runs through the ground and so forth so water natural water tends to be just slightly basic one thing I want to talk about this before we move on is this o h- the hydroxide and when I was first learning this I just want to clarify this is kind of like a side note thing that we're going to come back after that but the hydroxide I saw the o h- and one time I was actually teaching the class over sounds in water and so we said it's not a hydroxyl I said no it's had drunk said he said beta hydroxyl is always negative so I didn't know what tank he was talking about this was way back in the day so that's what actually led me to go look that stuff up the Hydrox ol hydroxyl spelt with a yl at the end is basically exact same thing o h- the hydroxide is exact same thing Oh h- and you will see this written all over the place sometimes as hydroxyl and sometimes as Hydrox I and people will mistakenly call it hydroxyl when they're referring the basis right here the proper term for that is the hydroxide so if you see that in a book I just want you to understand they look exactly the same the difference is the hydroxyl is generally when you use this compound in terms of organic chemistry containing the element carbon and most hydroxyls pertain to things like sugars alcohols and they are not basic meaning when you take a hydroxyl compound and dissolve that into water it will not break up to provide a no age group hydroxides on the other hand what we're dealing with is actually term for the inorganic compounds that are classified as basics meaning they do break up and provide a no age group when dissolved in water let's take a step forward down and let's move on and talk about alkalinity and when talking about alkalinity I want to start by just defining alkalinity there's a fantastic it's right here there's a fantastic book that I talked about my rave about this book all the time I'm not trying to promote it here I'll get that to promote it but Sacramento State University is a home study course you can take water treatment plant operation volume one it's a course I recommend people take by the way as a prerequisite if your state requires a prerequisite to taking your treatment exam it's also a fantastic course to take for continuing education anyway it has three definitions in that book it has three definitions in that book when it talks about alkalinity and we're going to go through each and of those three because I feel like by going all three of them it kind of helps beat it in one of those definitions in alkalinity is the capacity of a water to resist change in pH how alkalinity does that is it reacts with any additional hydrogen ions are floating around and neutralizing them okay so if you have a floating around hydrogen ion there and you have a floating around hydroxide there that hydroxide that hydrogen can combine together let's say it forms back in the water for this example here and therefore that extra hydrogen ion has been neutralized it's not floating around as an acid to make that water more acidic so again getting back to that definition the capacity of a water to resist a change in pH definition to the capacity of a water to neutralize acids or its acid neutralizing capability and by this it basically just means a total amount of bases that are contained in that water the more bases you have in the water the more things that can break apart supply this hydroxide ion the more hydroxides can be free in the water to tie up with those floating around hydrogen ions and then the third definition is a measure of how much acid must be added to lower the pH to 4.5 for the longest time I have this definition memorized here's the kind of stuff I was trying to stop you guys from going through with this video for the longest time I have this definition memorized and I took tests I passed tests the measure of how much acid must be added to water to drop a pH to 4.5 okay know a 4.5 min well why 4.5 4.5 is the point below which you have no alkalinity meaning all the alkalinity all the bases are in that water have been consumed by an additional by the hydrogen ions net water that tied up with all hydrogen ions and now below that we have three hydrogen ions because of that if you're ever doing a up and test for alkalinity and the pH and so forth you'll notice that as you add one acid to a water and it ties up those bases ties up those bases it'll drop slowly slowly slowly slowly once you hit 4.5 and all that alkalinity all those float around hydroxide ions there have been consumed once you pass that pH of 4.5 you'll notice that the pH not water will drop really quickly because now you add acid to the water there's nothing to tie it up as it's been added if you want to see a video that go check out my video on alkalinity I think it's uh it's alkalinity test I think is the name of the video you're racist for a second so that talks about the definition of alkalinity let's go ahead and talk about different forms and alkalinity can come in alkalinity mainly comes from the carbonates and bicarbonates of calcium and magnesium and these are just naturally occurring minerals and metallic salts that are just kind of out there in the earth calcium is a naturally occurring mineral it's most common form is calcium carbonate which laymen terms for calcium carbonate is limestone the water just kind of flows through the earth and over the earth and where there's limestone there it picks it up and that gets dissolved in the water and combines with the water molecules and adds alkalinity to the water we also use calcium carbonate treatment plants not so much specifically does it come in as calcium carbonate but we converted to calcium oxide because that's easier to transport and we use that as part of the lime slaking process so that when we're at the plant and we need to adjust the source waters we need to adjust the pH and alkalinity we do that so that's you'll see you'll hear a lot of that from there now getting back to magnesium again that's just making out main alloc and talking too much today magnesium is pretty much just metallic salts magnesium bicarbonate which is magnus t magnesium sulfate which epson salts are kind of just some examples of that so those are two things carbonates and bicarbonates of calcium and magnesium but there are a whole other group of things that can combine and form alkali groups or combinations of molecules or things that have alkalinity in them that can break apart at alkalinity into the water we refer to this whole group of molecules as alkalinity some of those other things are hydroxide or a silicate and phosphate so therefore alkalinity is actually a collection of many compounds and many chemicals that can react with those hydrogen the hydrogen ions that are raised off the board had to put it back as on that point ain't nothing they can react with those hydrogen ions and prevent them from appreciatively changing the pH of the solution so alkalinity can take many forms but it's measured in terms of carbonate hardness and it's expressed in terms of equivalent calcium carbonate why because it's the most common form but in addition to that I like to think of as kind of a common ground approach if you have two meters six inches and three feet how you going to tell someone how far something is so if we converted to meters six inches and three feet all to fiy it's a lot easier to work with so let's go ahead and talk about alkalinity and hardness alkalinity the calcium carbonate is a good thing it stops out water from the priest you typically changing one way or another it helps it resist that change in PH we want to make sure we have enough calcium magnesium to achieve that proper pH and alkalinity however the presence of calcium and magnesium in our water is not always a good thing because calcium and magnesium and high levels are also the cause of hard water which is very undesirable keeping an acceptable level is the trick we're going to talk about how to do that in just a little bit but for right now let's talk about some guidelines on hardness and like I said these are just general guidelines again calcium carbonate is measured in terms excuse-me alkalinity is measured in terms of calcium carbonate hardness is also measured to of calcium carbonate or equivalent calcium carbonate and it's expressed in milligrams per liter 15 is 60 milligrams per liter of calcium carbonate or equivalent calcium carbonate is said to be soft water now soft water is very bad it's very low in calcium carbonate it's very low in alkalinity it's very low in pH and can also be very acidic and very corrosive like I said at the very beginning of this video acidic waters commute away the mains it can cause holes it can cause all kinds of damage four main leaks and so forth but in addition to that they can leach the lead and copper out of pipes and into the water and you can consume a certain amount of that when you drink the water let in copper bad for you that's why they have rules and regulations regarding the maximum amount of that that can be in the water 60 to 100 milligrams per liter of equivalent calcium carbonate that's your sweet spot right there a hundred plus is considered hard water and the hard water is not good either it's these are waters that are high in calcium carbonate super high in alkalinity and high in pH and when your waters are high in pH and high enough the limiting calcium carbonate and all that they can cause a formation of soap curds actually stuff that comes out of the water and it causes an increased use of soap mainly an increased use of soap because they stop soaps from lathering up it basically stops that lathering process and inhibits a cleansing action of the soaps it also causes a deposition of scale in boilers because when they heat it up they can just become saturated come out of the water into it and I feel like a physical form and it cause clothes to lose softness or elasticity this is where the actual home loan of the average consumer they notice is that their soaps not sudsing up and that their clothes isn't soft it's kind of stiff you know they're walking around like wall-e the puppet boy in their clothes and their underwear or rough on them on that kind of stuff and people don't like that so one thing about these guidelines 50 to 60 saw 60 to 100 milligram for leader of equivalent calcium carbonate medium hundred-plus is hard these are general guidelines and I see these things all over the place but that's just kind of a general rule I've seen soft water considered something that was under 80 or 90 I've seen medium go from 90 to 120 I've seen hard be 120 to 130 plus so you'll see these kind of vary just keep in mind and that's a good ballpark people generally aren't going to give you as a question like 60 and ask you to tell that one way or another so let's talk about the forms of hardness right now hardness generally comes from calcium and magnesium again and there's three forms that it comes in calcium carbonate hardness non-carbonate hardness and total hardness and that's what this lovely little thingamajigger over here is for just to kind of explain them now carbonate hardness is caused when calcium step over this way carbonate is hardness is causing calcium and magnesium bond with carbonate and bicarbonate ions as I mentioned before alkalinity results primarily from the bond of calcium magnesium with carbonates and bicarbonates and it's also measured in terms of calcium carbonate so alkalinity in the water will equal the carbonate hardness this is termed temporary hardness because like I was saying before it can be boiled out of the water into an actual so weird I'm thinking about here I don't know the word I'm thinking of but it can be boiled out of the water in a particulate matter hey that's not a good okay so carbonate water is equal to your alkalinity it's termed temporary hardness because it can be boiled out of the water now non-carbonate hardness represents the calcium magnesium that is bonded with other things other than carbonates and bicarbonates so this is a calcium magnesium that's bonded with sulfides chlorides nitrites things like that and that is terms permanent hardness because it cannot be boiled out of the water so this is your carbonate hardness and this is your non-carbonate hardness then the combination of all of that is termed total hardness so total hardness is your combination of your carbonate hardness plus your non-carbonate hardness I kind of like to think of it as like the chlorine you have your free chlorine you have your combined chlorine and the two those together add up to total chlorine if you have no idea what I'm talking about please before you take a test go watch my video on break point Clark maybe it'll save your life probably not literally but it will save your test okay now just another thing to think about that would relate relationship to that if there is no non-carbonate hardness this is kind of simple if all the hardness in the water is in calcium carbonate form then carbonate hardness equals total hardness if you have more than obviously your carbonate hardness plus your non-carbonate hardness would equal your total hardness let's talk a little bit about carbonate saturation and water and how we actually measure that thing might mess up and create a new best so wrapping things up I want to talk about that calcium carbonate saturation in the water and how we exactly measure what that is so we know what to do with it we talked earlier about the balancing act of calcium carbonate with regards to hard and soft water and we talked about how water is considered stable when it's a perfect saturation with calcium carbonate at and given pH now a perfect equilibrium the waters neither scale forming nor is it corrosive if pH is raised from that point and everything else stays equal to what the carbonate participate parse it precip ah the carbonate precipitates out of the water and it actually becomes scale for me this causes a layer of scale to deposit on the inside of pipes and boiler process stuff like that if pH is lowered the water becomes corrosive no remember when we talked about pH at the very beginning we said a water of pH at 7 was neutral waters it's neither acidic nor is it basic let's assume for a second that the pH of saturation would be equal to the pH of 7 then it would be the exact same thing that's really simple so if the pH saturation was 7 then anything greater than that would be scale forming or basic would make it more scale forming anything less than that would make it more acidic so that it should be kind of a simple way to go your pH of saturation basically just adjusts this neutral point around and everything else kind of stays the same way so in like 1936 along comes this guy Wilfred or William Liang the leader and finds a way to make this really confusing then he names it after himself and now we gotta learn it all but really all it does is move that equilibrium point around and basically he invented this Langly index Langly or saturation index equals the pH measured minus that pH at saturation let's talk about how this works real quick for example let's say your pH that you actually measured in the water was a 5 okay so you went out you took your water sample and you're measured pH is a 5 but that that perfect saturation point is a 7 just like we had right here so the perfect saturation is 7 then what we would have is our measured pH minus our pH of saturation 5 minus 7 and that would equal a negative 2 now according to the length of their index a negative number means that the water can be corrosive no different that we could have figured out here just by doing like we did if the pH was 7 and we were less than the neutral point its negative and it's corrosive so you need to increase that pH by 2 to bring it back in equilibrium just on the opposite side of that let's do another one because mr. Lemle R made this so fun I'm sorry I want me to go off on it so much it's just some things just seem needlessly confusing so let's say the pH measured is an 8 this time okay so let's say our pH that we measured in the water is up here at 8 and this time instead of our pH at perfect saturation being like it ideal world was at 7 this time our pH a perfect saturation is 6 so now what we have is the pH measured which is 8 minus the pH of saturation which is 6 and you end up with a positive 2 now under the languidly Rin Dex positive numbers means the water has a tendency to form scale rather than doing all this it seems much easier just to move that saturation point over and look at it there so if this is if the perfect saturation of the equilibrium point is six and we're two above that that's a two and not only that but if you're on this side then it's scale for me that's kind of another way to think about it so that's the length a liter saturation index the last thing I want to talk about is a marble test and marble test is one of the simpler methods of determining calcium carbonate saturation it directly measures whether water is going to increase in hardness and pH when it's dosed with calcium carbonate so very very simple five-step process one you measure the pH the alkalinity and the hardness of the water - yeah add calcium carbonate and then you stir the water and three you re measure the water for pH alkalinity and hardness if they've increased that means that that calcium carbonate that you added was absorbed into the water it was under saturated if they decrease it was supersaturated now by decrease what I mean is your initial dose plus what you added was kind of down some of that participer TQ lated precipitated out and so you know it was supersaturated so that's kind of an overview of the pH alkalinity and hardness and I hope you enjoyed it and I hope I at least gave you a good foundation and make it easy to understand this is kind of rough to soak in you might want to go up and watch this video second time to help things kind of absorb into the brain we covered an absolute lot of stuff also the water seafood podcast if you haven't ever heard of it you should really go check it out ww-who says that anymore right water sifu and since nobody knows what a situ is it'll be at the end of the video why am I doing this water seafood calm there's a whole bunch of free audio podcasts you can download your phone and take with you on the go I do want on water chemistry there I believe it's number onee but anyway hope you found that well and we will talk to you later have a good day and good luck on your exams

Channel: TheWaterSifu

Views: 144,195

Rating: 4.8993435 out of 5

Keywords: pH, Alkalinity, Hardness, Acids, Bases, Carbonate, Langelier Index, Marble Test, Hydroxide, water treatment

Id: 2MI_5T8GHLA

Length: 28min 29sec (1709 seconds)

Published: Thu Aug 27 2015