Water Quality Project (Iron, Hardness, Arsenic)

Discussion in 'Water Softener Forum, problems, installation and r' started by robertt, Jun 30, 2013.

  1. robertt

    robertt New Member

    Messages:
    7
    Location:
    boise, ID
    I am in the early stages of a water quality project. We have a mountain house that we have been working on for a few years but still not quite able to stay up there yet. The symptoms we have are reddish water out of the taps and a lot scale built up and iron staining on brand new toilets that have been lightly used in the last year. I had a water test done to see if it was safe, I didn't know what all to test for so I picked arsenic, coliform, and iron(I could see the staining already). Other subjective data: no sulfur smell, no slime in the toilet tank.

    The results:
    coliform negative
    Iron 1.04 mg/L
    Arsenic .053 mg/L

    I know I don't have enough info to move forward so my first question is what do I need for water tests? There is a company called Aquaknow that will test for this list for $100.

    Chemicals – Metals
    Aluminum 0.1
    Arsenic 0.005
    Barium 0.30
    Cadmium 0.002
    Calcium 2.0
    Chromium 0.010
    Copper 0.004
    Iron 0.020
    Lead 0.002
    Magnesium 0.10
    Manganese 0.004
    Mercury 0.001
    Nickel 0.02
    Selenium 0.020
    Silver 0.002
    Sodium 1
    Zinc 0.004
    Inorganic Chemicals and Physical Factors
    Alkalinity (Total as CaCO3) 20
    Chloride 5.0
    Fluoride 0.5
    Nitrate as N 0.5
    Nitrite as N 0.5
    Sulfate 5.0
    Hardness 10
    pH (Standard Units) —
    Total Dissolved Solids 20
    Turbidity (Turbidity Units) 0.

    Any recommendations on what to test and who to test it would be appreciated. Do I need to know dissolved oxygen?


    The iron topic is a little confusing also. It seems there are three types:
    ferrous iron- clear water iron, water starts out clear and then turns red after it has a chance to oxidize
    ferric iron- comes out of the tap red but the rust particles settle in time
    colloidal iron- oxidized iron where the particle size is very small and it is bound to an organic. Will never settle to the bottom.

    Is there a lab test to distinguish what I have? the toilet water always has a tint(seems more yellow than red) so I was thinking maybe I have the colloidal version. I would love some suggestions on how to distinguish.

    The arsenic is a whole different animal. I found one link that implied you could reduce arsenic with a iron filter and an ion exchange system(regular water softener?) Here is the link
    . The thought being if have an oxidizing media then some of the arsenic will bind to the iron and can then be filtered out. In the ion exchange system apparently one type of arsenic(As V) will bind to the exchange media. It competes with sulfates so your water needs to be low in sulfate content. Is there a way to know what type of arsenic you have?

    I have already asked a ton of questions so I will stop here.... First thing is to get the right testing done.
    thanks
    ...robert
  2. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

    Messages:
    2,714
    Location:
    Central Florida
    Idaho seems to have a pretty strong interest in water. Google "university idaho county extension water test" for over 96M hits. Two publications -- CIS 873 and CIS 895 -- are immediately relevant. Contact the Extension agent in your county for information about water testing in your area. In Florida, you can get a sample tested for $9 covering the most common issues.
  3. ditttohead

    ditttohead Water systems designer, R&D

    Messages:
    1,815
    Location:
    Ontario California
    The full test is a good idea. You should also own a pocket style TDS meter ($20) and a Hach 5B hardness test kit ($35). These are very basic tests that will give you information especially if you see any major changes in these 2 tests, you should consider having your water retested.

    That being said, certain iron filters do a good job of arsenic removal for the reasons you stated. We usually recommend an alternate (secondary) arsenic treatment method. Titanium oxide, GFH, RO, etc. is always advised, and required in many areas.

    Regular basic tests to ensure your equipment is operating properly is also important.
  4. robertt

    robertt New Member

    Messages:
    7
    Location:
    boise, ID
    Mikey, I got a hold of the University of Idaho and talked to their lab. I was getting encouraged until I realized they don't do drinking water. The reason they don't as well as the county extension doesn't is they aren't allowed to compete with private labs. The local lab is pretty expensive so at this point I haven't seen any thing better than the Aquaknow site I mentioned above. I will pull the trigger on that I guess.

    Ditto, have you found that whole house arsenic removal is practical in most cases? I was thinking that I might be able to get a decent reduction and then may have to go will an RO system under the sink.
  5. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

    Messages:
    2,714
    Location:
    Central Florida
    Sorry to have misled you. But hardness is hardness, whether you drink it or not, so next time tell 'em you're wanting to grow orchids or use it in an aquarium and see what happens. I'll check with our local office to see what the scoop is here as well; it might depend on the political climate of the state. In any event, the UF form used to request a test says "analysis of irrigation water or household well water", but explicitly excludes "municipal or drinking water". I take the latter to mean they won't test any community water (they're required to do that themselves and report annually) or bottled water. See http://www.cdc.gov/healthywater/drinking/public/faq.html for some interesting FAQs, including:

    "If you want to test your water, your local health department should assist in explaining any tests that you need for various contaminants. If your local health department is not able to help you can contact a state certified laboratory to perform the test. To find a state certified laboratory in your area call the Safe Drinking Water Hotline at (800) 426-4791 or visit the State Certified Drinking Water Laboratories[​IMG] list."

    Aquaknow is Idaho-certified, and probably will test anything.
    Last edited: Jul 2, 2013
  6. robertt

    robertt New Member

    Messages:
    7
    Location:
    boise, ID
    Ok, I finally got my water test results back. I was surprised that I do NOT have hard water. This agrees with the Hach 5B test kit I just received also. I guess all the stains I see are just from the iron and what ever is causing the turbidity. I knew I had the arsenic but the fluoride was a surprise. While I was waiting for the results I did do an experiment by setting out a glass of the water to see if anything would settle out. I don't think anything did, it doesn't seem any clearer and I don't see any rust or other sediment on the bottom. I set a second glass out and I put a little bleach in it, this cleared it up some but not as clear as my main residence on city water.
    The house also has a GE whole filter, I don't know much about but the similar GE filters I see online have a 20 micron filter. For my turbidity it doesn't seem to help at all. I guess that speaks to the size of the particulate.

    So, I am open to suggestions here on how to treat this water.....

    A few details about the house. This is a vacation mountain house with 2.5 baths. Most of the time there will be nobody there, other times there will be 2 of us and sometimes we will have family and there may be 12 people so the demand is all over the map. The well has pretty good flow rate at the pressure tank. I timed how long it took to fill the pressure tank but I can't remember. I can time it next time I am up there. I'm guessing a hose hooked up to the spigot on the pressure tank will flow close to 20gpm though.

    Thanks in advance for any recommendations.
    ...robert







    Aluminum ND mg/L 0.2 EPA Secondary 0.1
    Arsenic 0.043 mg/L 0.010 EPA Primary 0.005
    Barium ND mg/L 2 EPA Primary 0.30
    Cadmium ND mg/L 0.005 EPA Primary 0.002
    Calcium ND mg/L -2.0
    Chromium ND mg/L 0.1 EPA Primary 0.010
    Copper 0.011 mg/L 1.3 EPA Action Level 0.004
    Iron 1.090 mg/L 0.3 EPA Secondary 0.020
    Lead 0.004 mg/L 0.015 EPA Action Level 0.002
    Magnesium ND mg/L -0.10
    Manganese 0.029 mg/L 0.05 EPA Secondary 0.004
    Mercury ND mg/L 0.002 EPA Primary 0.001
    Nickel ND mg/L -0.020
    Potassium 2.8 mg/L -1.0
    Selenium ND mg/L 0.05 EPA Primary 0.020
    Silica 30.0 mg/L -0.1
    Silver ND mg/L 0.100 EPA Secondary 0.002
    Sodium 56 mg/L -1
    Zinc 0.961 mg/L 5 EPA Secondary 0.004

    Physical Factors
    Alkalinity (Total as CaCO3) 68 mg/L -20
    Hardness ND mg/L 100 NTL Internal 10
    pH 7.4 pH Units 6.5 to 8.5 EPA Secondary
    Total Dissolved Solids 180 mg/L 500 EPA Secondary 20
    Turbidity 3.2 NTU 1.0 EPA Action Level 0.1

    Inorganic Analytes - Other
    Chloride ND mg/L 250 EPA Secondary 5.0
    Fluoride 6.1 mg/L 4.0 EPA Primary 0.5
    Nitrate as N ND mg/L 10 EPA Primary 0.5
    Nitrite as N ND mg/L 1 EPA Primary 0.5
    Ortho Phosphate ND mg/L -2.0
    Sulfate 43.0 mg/L 250 EPA Secondary 5.0
  7. ditttohead

    ditttohead Water systems designer, R&D

    Messages:
    1,815
    Location:
    Ontario California
    Whole house filtration for the turbididty/iron, etc,

    Arsenic/Fluoride are typically reduced 90% by R.O. Be sure the RO has a membrane rejection rating of 98% or more. Many high flow membranes will have ratings in the 90+% range.

    You may also want to consider some form of redundancy for the drinking water. An Activated Alumina post filter (after the membrane, not on the way to the faucet) will remove the remaining Arsenic and Fluoride for a minimal cost.

    Now it comes down to a budget issue. How good do you want your water, how much maintanence, and how much money do you want to spend?

    Thanks for getting a real test. It is rare, but some people would actually discourage spending money on proper tests, including some water treatment dealers. Now that we know the problems with your water, a treatment method that will provide you with safe drinking water can be discussed intelligently.
  8. robertt

    robertt New Member

    Messages:
    7
    Location:
    boise, ID
    Thanks Ditto,

    When you say a whole house filter are you talking about a regular backwash filter with something like a Mang Ox or similar media? If so I didn't realize that approach would help the turbidity.

    I assume the RO comments are only for drinking water only?

    My budget? Good question, it's not like I can not fix it somewhat, the water is terrible. I guess if I can get the water to not stain all the new fixtures and get a localized source for drinking water that would be great. I was starting to get calibrated to a $1k backwashing filter of some sort followed by a $500 undersink RO filter. Is this even close to what you are thinking?
  9. ditttohead

    ditttohead Water systems designer, R&D

    Messages:
    1,815
    Location:
    Ontario California
    The term Whole house filtaration is used generically. You have a minor problem with your iron and turbidity. Some traditional methods of Chlorine, Contact tank/GAC will eliminate the iron but it will probably not take care of the turbidity. A better appraoch may be a proper chlorine injection system, contact tank, and Turbidex or similar media. GAC will filter out large stuff in the water but it does not have a technical rating for micron filtration. GAC will allow for the over-injection of Chlorine since it will easily remove excess chlorine. Turbidex will remove down to the 3-5 micron range but will not remove chlorine so a controlled chlorine dose is very important.

    I would lean toward a simple chlorine injection system, contact tank, and a backwashing turbidex filter (clinptilolite, micro-z, filter ag+ are all similar medias) to keep the cost low and the water quality higher.

    A RO system at the sink with some form of redundancy (post arsenic/fluoride filter) would be important.

    Other pros on this board will have different ideas. Lets see what else gets recommended.
  10. robertt

    robertt New Member

    Messages:
    7
    Location:
    boise, ID
    Thanks Ditto, no one else jumping in here with any other ideas so I'll ask a few questions. Do you have a recommendation for the injection system? How big does the contact tank need to be? There is already installed a sand trap that is really the same as a resin tank, it has a down tube so the water goes in on the bottom and it exits at the top. It doesn't seem to catch any sand so I was thinking of taking it out to make more room for whatever backwashing filter I end out with. I could leave it in if it would help but I'm guessing it would only have a volume of 10 - 15 gallons.
  11. robertt

    robertt New Member

    Messages:
    7
    Location:
    boise, ID
    Another question---

    From a functional standpoint, would you accomplish the same thing if you had a MangOx(or equiv) filter followed by a Turbidex filter? With the MangOx filter there is a good shot a getting meaningful reduction of arsenic. If that is true then that might play pretty big. Is the arsenic oxidized such that it can be reduced by the Turbidex filter also?

    From a cost standpoint I guess it would be comparing the cost of the chlorine injector + mixing tank with the MangOx filter. Seems like it would be pretty close.
  12. Tom Sawyer

    Tom Sawyer In the Trades

    Messages:
    3,127
    Location:
    Maine
    I can think of more expensive ways to do this but the recommendation above would be what I would also recommend.
  13. ditttohead

    ditttohead Water systems designer, R&D

    Messages:
    1,815
    Location:
    Ontario California
    Arsenic remal with magnesium oxide based medias can be part of the equation, but they typically rely on iron being present in the water to work effectively for arsenic reduction. no iron = no arsenic reduction. So if your water supply changes, and you start to have less iron in the water, the ability to remove Arsenic may go away. many of our customers use this method, but they always have an Arsenic specific removal method that is not reliant on iron. GHF, titanium dioxide, etc. can be used and the media life can be extended greatly by using the magnesium oxide based medias first.

    Iron removal with magnesium oxide can be very effective assuming you have enough oxygen in the water.
  14. robertt

    robertt New Member

    Messages:
    7
    Location:
    boise, ID
    How would I test for oxygen content to gauge the likely effectiveness of the magnesium oxide filter?

    Your comment about the final media that is removing the arsenic lasting longer if you successfully remove some upstream is what I was thinking also. The people that sell the MangOx filter also claim in the marketing hype that it will also take care of turbidity. Thoughts on this? I'm wondering if there is a way to further quantify the turbidity to better know if that filter would work.

    Maybe I start with a magnesium oxide filter and see what it gets me.

    Any of this going to have any effect on the floride?
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