The document discusses the significance of water analysis, particularly focusing on the determination of organic pollutants using various methods such as Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), and Total Organic Carbon (TOC). It presents the challenges associated with traditional analysis methods and highlights the advantages of TOC analysis as a faster and safer alternative. Additionally, it emphasizes the importance of water protection and innovative analytical technologies in environmental monitoring.

1. Screening parameters in water analysis
31.08.2015
Ralf Dunsbach
Webinar

2. The elementargroup – About us
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• The technology leader in
• Elemental Analysis (EA)
• Isotope Ratio Mass Spectrometry (IRMS)
• Offers an unmatched combination of
• innovative technologies,
• tailor-made solutions and
• comprehensive support.

3. The elementargroup – Key Markets
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AgricultureChemicals EnvironmentalEnergy MaterialsForensics

4. Tailor-Made to Customer Needs
• Elemental analyzer optimized for different analytical tasks
• vario Series - Industry-leading versatility in elemental analysis
• rapid Series - Dedicated instruments serving today’s customer needs
• trace Series - Trace-level detection of elements
• TOC Series - Fast and easy determination of total organic carbon
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5. Screening parameters in water analysis
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Water analysis
The main focus within environmental analysis is
the subject of water. Our instruments are used to
carry out routine analysis of organic impurities in
the water industry.

6. Introduction
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H2O
Contains
• Inorganic compounds (salts like NaCl)
• Organic compounds (humic substances + man-made
waste)
Only 0,3% of the global water resources is availble as drinking water
Water protection, technology and analysis
gain more and more importance!
One of the most important quality criteria for
water is Pollution with organic compounds

7. How to determine organic pollutants
Pollution with organic compounds - how to determine?
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Single compound analysis
by chromatographic methods?
Drawback:
Nearly impossible due to the huge
number of possible compounds –
applicable only for certain classes of
substances (e.g. polycyclic aromatic
hydrocarbons)
Screening parameter analysis
for all organic compounds
- BODx - biological oxygen demand
- COD - chemical oxygen demand
- TOC -total organic carbon

8. How to determine organic pollutants
BODx and CSB are indirect methods to determine the amount of organic
carbon by the determination of the biological and chemical oxygen demand
during the decomposition of its compounds.
Disadvantage:
• slow
• insufficient or wrong oxidation
• depending from biological activity
• heavy metal containing reagents
• no automation
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9. BOD5 - biological oxygen demand
after 5 days
DIN 38 409 H51
DIN 38 409 H52
Disadvantage:
particulates are not sufficiently
oxidized
slow (5 days)
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Reference: Fonds der chemischen
Industrie - Umweltbereich Wasser
BOD

10. DIN 38 409 H41
Disadvantage:
higher or fluctuating results,
if dichromate is consumed due to the
oxidation of sulfur containing compounds
Reagents:
concentrated sulfuric acid H2SO4 – corrosive!
potassium dichromate K2Cr2O7 - toxic!
mercury substance (masking of chloride) –
toxic!
Analysis time: > 2 hours,
automation very difficult
Dichromate out of use in EU
latest 2017!!
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Reference: Fonds der chemischen
Industrie - Umweltbereich Wasser
COD

11. Recovery rates COD
According to Janicke (WaBoLu report 1/1983):
n-hexane 2% Urea 82%
Cyclohexane 5% benzene 63%
Chloromethane 8% EDTA 78%
Trimethylamine 1% starch 91%
Nicotinic acid 12% stearic acid 60%
Poor recovery for alcanes, amines
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12. False COD readings
• High false readings by chlorides, bromides, iodides, certain sulfur
compounds, nitrites and certain metal compounds
• False low readings by chromium (VI)-compounds, nitrates, peroxides
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13. TOC
EN 1484 - European Standard
Water analysis -
Guidlines for the determination of the total organic carbon (TOC) and
dissolved organic carbon (DOC)
The EN 1484 approves the determination of TOC and DOC as appropriate
method to determine the contamination of water with organic compounds.
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R-C + O2  CO2 + H2O + further products

14. TC
TC [total Carbon] = TIC [total inorganic carbon] + TOC [total organic carbon]
TOC = POC [purgable organic carbon] + NPOC [non-purgable organic carbon]
TOC + TIC
POC + NPOC
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TOC

15. TC [total Carbon]
Oxidation Detection
Sample [R-C-R + CO3
2-] + O2  CO2 + H2O +
...
Total carbon can be determined by oxidation and decomposition
of the sample and detection of the deriving CO2
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How to determine TC

16. Detection
Acidified Sample: CO3
2- + 3 H+  CO2 + H3O+
TIC
Total inorganic carbon can be determined by degradation of the
carbonates by acid, purging and detection of the deriving CO2
Gas
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How to determine TIC

17. NPOC [total Carbon]
Oxidation Detection
Acidified and purged Sample [R-C-R ]
Non-Purgable Organic Carbon can be determined by purging
the acidified sample in advance to remove TIC and POC,
oxidation of the remaining components and detection of the
deriving CO2
Oxidation:
R-C-R(non vol.) + O2  CO2 + H2O + ...
Purging:
[R-C-R (volatile and non volatile) + CO3
2-] + 3 H+  CO2 + H3O+ + R-C-R
(vol.)
if POC = 0

NPOC = TOC
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How to determine NPOC

18. Method Advantages Disadvantages
Differential:
TOC=TC - TIC
includes volatile organic compounds Less suitable for high TIC
concentrations
(TOC << TIC)
long measuring times
Direct: NPOC
Non-purgeable organic carbon
= TOC in case no volatile
compounds are present
suitable for high TIC concentrations
(TIC >> TOC)
fast results
Does not include volatile
organic compounds if present
in the sample
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How to determine TOC

19. EN 1484 - European Standard
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Determination of TOC and DOC by:
• Wet chemical - UV-persulfat method (DOC only)
• Combustion method
How to determine TOC

20. How to determine TOC
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Wet chemical - UV-persulfat method
Quelle: Deutschen Bundesstiftung Umwelt (DBU)
R-C + O2 CO2 + H2O + further products
UV-light +
oxidation agent
Advantage:
• large sample volume (up to 20mL)
• high sensitivity
Disadvantage:
• insufficient oxidation of particulates
• not applicable for electrolytes or
chlorine containing samples
• not for highly contaminated samples
• not for solid samples
• not for nitrogen

21. Elementar Webinar 2015
Combustion method
R-C + O2 CO2 + H2O + further products
Advantage:
• quantitative oxidation of all carbon
containing compounds
• low matrix influence
• applicable for waste water and solids
• applicable for TNb as additional parameter
Disadvantage:
• lower injection volume
• problematically with salts
• lower sensitivity
High temperature in
presence of catalyst
How to determine TOC

22. State-of-the-art TOC analyzer
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23. The Concept
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24. Easy maintenance
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• Temperatur programmable up to 1100°C
• Matrix separation (patent pending) to keep salt
away from the catalyst
• Multiway valve on top of the combustion tube for
fast and easy injection
• All maintenance parts easily accessible

25. Solids analysis
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• Only TOC in water analyzer worldwide with
automatic sample feeder for solids
• Sample feeding by reliable ball valve technique
• Sample carousel with 80-120 positions
• Solids expansion kit for carbon amounts up to
20mg C abs.

26. Drinking water: 0.5 ppm – 2 ppm TOC
Surface waters: 0.5 ppm – 10 ppm TOC
Waste waters: 5 ppm – 10,000 ppm TOC
Waste and soil: upper ppm to percentage range of TOC
Waters in pharmacy: 0.05 – 0.5 ppm TOC
Waters in power plants: 0.05 – 1 ppm TOC
Waters in semiconductor industries: 0.005 – 0.5 ppm TOC
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Typical TOC contents

27. Correlation TOC/COD
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Oxalic
acid
Ethanol
Both compounds have the same TOC (in
mol/l), but COD is 5* higher than oxalic acid.

28. COD/TOC of certain compounds
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29. COD/TOC in different samples I
Origin COD/TOC SD
Influent MWWTP <1000 r 3,23 0,42
Influent MWWTP 1000-5000 r 3,16 0,41
Influent MWWTP 5000-10000 r 2,99 0,37
Influent MWWTP 10000-100000 r 2,99 0,37
Influent MWWTP >100000 r 2,92 0,39
Edible oil refinery 3,64 0,70
Fish processing 3,51 0,45
Meat industry 3,26 0,41
Glue production 4,28 1,62
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MWWTP: municipal waste water treatment plant

30. COD/TOC in different samples II
Origin COD/TOC SD
Ore processing 4,05 0,15
Sugar production 2,92 0,36
Paper production 2,75 0,18
Iron+steel production 3,78 1,02
Textile production 3,05 0,27
Glas and inorganic fiber production 2,62 0,25
Chemical cleaning 3,64 0,24
Waste deposit 3,04 0,2
Oil refineries 3,32 0,25
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Source: Verbesserung der Einleiterüberwachung durch die Einführung der Meßgrößen TOC, TNb and Pges., Wasserwirtschaft
Forschungsbericht 296-22-322

31. Summary
• TOC analysis require minimum manpower
• TOC can be measured within 4 minutes
• The only chemicals required for TOC are diluted, non-oxidizing mineral
acids
• No special workbench (fume) required for TOC
• Therefore: it needs some work to replace COD by TOC, but
it‘s worth it!
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32. Elementar thanks for your attention!
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