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How to measure organic matter in water



Measuring organic matter, or the remains of organic compounds in the water, can help you track the health of your body and the organisms that live in it. If you have access to laboratory equipment, you can measure the total biodegradable dissolved organic carbon (BDOC) or the amount of chemical oxygen demand (COD) in your water. If you do not have access to lab equipment, you may want to consider sending a sample to a lab in your area.

[ Edit ] Step

[ Edit ] Collect a sample

  1. Select an area of ​​the water that is slow or still. Water that moves quickly is harder to sample because the organic matter swirls in it. Find an area of ​​water that is either slow or still to get an exact sample. [1]
      Measure Organic Substances in Water Step 1.jpg
    • If there are no areas of slow motion or still water nearby, you can take a sample from a fast moving area. However, it may not be as accurate.
  2. Drop a weighted bottle into the water. Attach a weight or stone to a glass bottle and attach it to a yarn length. Immerse the bottle in the water until it hits the bottom. [2]
      Measure organic matter in water Step 2.jpg
    • A lot of sampling containers have been tested and discarded, and while a bottle is not perfect, it is the most universally available.
  3. Wait for about 2 minutes to allow the water to settle. If you stand near the bottle, keep still so that you do not kick up sediment particles. Wait for about 2 minutes, leaving the bottle in the water at all times. [3]
      Measure organic material in water Step 3.jpg
  4. Slowly take the bottle back up and put on the lid. Pull the length of yarn to which the bottle is attached and lift it out of the water. Screw on the lid so that the sample is airtight and it will not spill out. [4]
      Measure Organic Material in Water Step 4.jpg
    • If you like, take some samples so you can get an average of the whole water.
  5. Keep the sample in the fridge until you can test it. Make sure your refrigerator is set to keep the sample cool, but not frozen. Ideally, you should take your sample just before you test it, but if you need to store it, you can put it in the fridge. [5]
      Measure Organic Matter in Water Step 5.jpg
    • The earlier you test your sample, the more accurate your results will be.

[ Edit ] Measurement of BDOC

  1. Pour the sample through a 2 µm pore size filter. Measure out your total sample and put the rest aside for later use. Place a filter over a glass jar and pour your sample through the filter. Ensure that all major organic substances have been removed from the sample before you begin testing. [6]
      Measure organic matter in water Step 6.jpg
    • Make sure your filter is completely clean before using it to avoid contamination.
    • Large parts of sediment can contaminate your sample and disrupt the results.
    • BDOC is the total biodegradable dissolved organic carbon in the water, and it can help you determine how many bacteria are living in your body.
  2. Add autochthonous bacteria to the sample. Autokton bacteria are bacteria that were already present in the water sample. After testing the sample, add the unfiltered water back to the glass jar. [7]
      Measure organic matter in water Step 7.jpg
    • Putting the bacteria back in the water will tell you how much biodegradable carbon is present, not just carbon in general.
  3. Take water from the sample. Now measure the inoculated sample and divide it into two sub-samples. Put the water in glass jars that have lids on them for future storage. This will make testing easier and on a smaller scale. [8]
      Measure organic matter in water Step 8.jpg
  4. Measure the samples with a Dohrman 80 Total Carbon Analyzer. Place the samples upright in the carbon analyzer and close the plastic lid. Turn on the machine and look at the screen to see when it starts the measurements. Wait until the numeric reading on the front of the machine registers your first dissolved organic carbon, or DOC, reading. [9]
      Measure Organic Material in Water Step 9.jpg
    • Dohrman 80 Total Carbon Analyzer works by heating samples to an extreme temperature and then using UV light to measure carbon levels.
    • You can also use this machine to test total organic carbon, or TOC.
    • For more accurate results, test each sample twice and then take the average of the readings.
  5. Store the samples in the dark for four weeks. Place the sealed samples upright in the refrigerator set to. Keep the door closed so that the samples remain in the dark for 4 weeks, or 28 days. [10]
      Measure organic matter in water Step 10.jpg
    • Darkness allows the bacteria to eat through the carbon to give you your results
  6. Measure each sample again with a Dohrman 80 Total Carbon Analyzer. Take your samples out of the fridge and put them back in the carbon analyzer. Turn it on and wait for the reading to give you your final DOC number for each sample. [11]
      Measure Organic Material in Water Step 11.jpg
    • If you want, you can take two readings of each sample again and average them out.
  7. Subtract the final DOC from the original DOC to obtain the BDOC. Take the average of all four readings to get the most accurate results. Your BDOC will be measured in parts per million, or mg / liter. [12]
      Measure organic matter in water Step 12.jpg
    • For example, if the initial DOC reading was 9.6 and the final was 7.8, the BDOC is 1.8 parts per million, or 1.8 mg / liter .
  8. Analyze your results based on the type of water body you have. The BDOC level in water may be due to many factors, but if there is a lot of bacteria in your water that breaks down carbon, it is probably not advisable to drink without further filtration. High BDOC, or BDOC over 1 part per million, is not necessarily bad in all water bodies. [13]
      Measure Organic Material in Water Step 13.jpg
    • If you are concerned about the levels of biodegradable carbon in your water, talk to an expert on waste management.

[ Edit ] COD Testing

  1. Separate your sample into a test tube. You do not need your entire water sample to determine the chemical oxygen demand. Set the rest of the sample aside if you want to use it for more testing. [14]
      Measure organic matter in water Step 14.jpg
    • You can also test several test tubes at a time and average results for more accuracy.
    • COD is the total chemical oxygen demand and it can show you how much oxygen is used in your body.
  2. Prepare a test tube with mineral water. Make sure the water is pure mineral water with no additives. You will use this test tube together with your test tube to find out the final equation. [15]
      Measure organic matter in water Step 15.jpg
    • The mineral water pipe is also called "empty."
    • You can find mineral water in most grocery stores.
    • You must do the same step for the sample and the mineral water to get a comparison for your final equation.
  3. Add 1 g of magnesium sulfate, then leave the mixture to stand for 5 minutes. Take a small pipette and slowly add magnesium sulfate to the sample and the mineral water tube. Take time and make sure you do not overload any of the pipes. Leave your mixture on the counter for 5 minutes to allow the solution to dissolve. [16]
      Measure organic matter in water Step 16.jpg
    • You need to walk slowly so that magnesium sulfate can be absorbed into the water.
  4. Add 1 g of silver sulfate and some glass beads. Heat 3 to 4 glass beads for 1 hour. Add 2 beads to each test tube when adding 1 g of silver sulfate to each tube. [17]
      Measure organic material in water Step 17.jpg
    • The glass beads give the liquid in each tube a large surface area so that it can cool and warm quickly.
  5. Cool the sample in ice water and then add 75 ml of sulfuric acid. Immerse the tubes quickly in ice water and be careful not to get any water in the tubes. Leave them for 3 to 5 minutes until cooled to room temperature and then add the sulfuric acid. [18]
      Measure organic matter in water Step 18.jpg
    • Be careful when applying sulfuric acid and try not to get it on the skin.
    • If you get sulfuric acid on your skin, rinse it with cold water immediately.
  6. Add 25 ml of potassium dichromate. Use a clean pipette to drop potassium dichromate into each test tube. You do not need to go slow, so you can add all 25 ml at once. [19]
      Measure organic matter in water Step 19.jpg
    • Your sample may change colors at this point, which is normal. [19659009] Place the tubes on a condenser and leave it for 2 hours. A condenser cools hot gas into liquids. Insert all your test tubes into the condenser and leave it on for 2 hours to turn your sample. [20]
        Measure organic matter in water Step 20.jpg
      • Make sure you keep track of time. If you leave your samples on the condenser for too long, your results may be.
    • Add mineral water to each tube and then cool them to room temperature. Turn off the condenser and let them cool enough so you can touch them, or for about 2 minutes. Add enough mineral water to each test tube to create total fluid in each tube. Leave the test tubes out on the counter for 10 to 15 minutes until completely cool. [21]
        Measure organic matter in water Step 21.jpg
      • If your test tubes are too small, transfer the liquid to a larger glass container
    • Titrate the sample with Ferroin indicator solution. Use a pipette to slowly add Ferroin indicator solution 1 drop at a time. Keep track of how many drops you use for both the mineral water pipe and your actual test tube. [22]
        Measure Organic Matter in Water Step 22.jpg
      • It is very important to count how many drops you use in each, since you will use that number in your final calculation.
    • Stop titrating when the color turns reddish brown. The goal is to turn your sample from a green / blue color to a red / brown color. Once the sample is changed, stop the titration and write down how many drops of indicator solution you used. [23]
        Measure organic matter in water Step 23.jpg
    • Determine COD by comparing the test tube with Mineral water. First, subtract the amount in ml of indicator solution you used on the actual sample from the amount of indicator solution you used on the mineral water. Then multiply that number by 0.1, which is the normality of the indicator solution you used. Multiply that sum by 8,000, then divide that number by to get your amount of chemical oxygen demand in parts per million, or mg / liter. [24]
        Measure Organic Matter in Water Step 24.jpg
      • For example, if you used 4 ml in your actual sample and 20 ml in your mineral water, subtract 20 – 4 to get 16. Then multiply it by 0.1 for to get 1.6. Multiply 1.6 x 8,000 to get 12,800, then divide it by 50 ml (your sample size) to get 246 mg / l.
    • Aim for a COD of 10 to 30 mg / L for a contaminated body. If COD is 10 to 30 mg / L it is not contaminated. If COD is 25 to 50 mg / L, it is easily contaminated. If COD is 250 mg / L, it is wastewater. [25]
        Measure organic matter in water Step 25.jpg
      • If you are concerned about the amount of COD in your water, contact a waste management specialist.

[ Edit ] Tips

  • Test your sample as soon as possible for the most accurate results.

[ Edit ] Warnings

  • Always read the manuals for all laboratory equipment before using it.
  • If you are unfamiliar with lab equipment or chemicals used in the testing process, submit your sample to a lab for professional evaluation.

[ Edit ] Things You Need

[ Edit ] Collect a sample

  • glass bottle with a lid
  • Weight
  • Twine

[ Edit ] Measurement of BDOC

  • Filter
  • Glass jars
  • Dohrman 80 Total Carbon Analyzer

[ Edit ] Testing C OD

  • Test tube
  • Mineral water
  • Pipette
  • Magnesium sulphate
  • Silver sulphate
  • Glass beads
  • Sulfuric acid
  • Potassium dichromate
  • Condenser
  • Ferroin indicator solution [194590

    [ Edit ] References

    1. https://pubs.usgs.gov/twri/05a03/report.pdf
    2. https: / /pubs.usgs.gov/twri/05a03/report.pdfebrit19659125strong↑ https://pubs.usgs.gov/twri/05a03/report.pdf
    3. [1945 https://pubar.usgs .gov / twri / 05a03 / report.pdf
    4. https://pubs.usgs.gov/twri/05a03/report.pdf
    5. https://aem.asm.org / content / aem / 55/10 / 2732.full.pdf
    6. http://www.seas.ucla.edu/stenstro/j/j62
    7. https://aem .asm.org / content / aem / 55/10 / 2732.full.pdfebrit19659131 ?? ↑ https://www.ru.nl/science/gi/facilities-activities/elemental-analysis/toc/ [19659129] ↑ https://aem.asm.org/content/aem/55/10/2732.full.pdf
    8. https://aem.asm.org/content/ aem / 55 / 10 / 2732.full.pdf
    9. https://aem.asm.org/content/aem/55/10/2732.full.pdf
    10. h ttps: //aem.asm.org/content/aem/55/10/2732.full.pdfebrit19659136??↑ ht tps: //pubs.usgs.gov/twri/05a03/report.pdf
    11. [1945 https://pubs.usgs.gov/twri/05a03/report.pdf
    12. https: //pubs.usgs.gov/twri/05a03/report.pdfebrit19659139??↑ https://pubs.usgs.gov/twri/05a03/report.pdf
    13. [1945 https: // pubs.usgs.gov/twri/05a03/report.pdfebrit19659141achte↑ https: // pubs.usgs.gov/twri/05a03/report.pdf
    14. https: // pubar. usgs.gov/twri/05a03/report.pdfebrit19659143vard↑ https://pubs.usgs.gov/twri/05a03/report.pdf
    15. https://pubs.usgs. gov / twri / 05a03 / report.pdf
    16. https://pubs.usgs.gov/twri/05a03/report.pdf
    17. https://pubs.usgs.gov/ twri / 05a03 / report.pdf
    18. https://pubs.usgs.gov/twri/05a03/report.pdf

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