CHEMSCAN
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      • Ammonia Feed
      • Chloramination Control
      • Chlorination
      • Color Analysis
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      • Ion Exchange Breakthrough
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      • Peak Point Chloramination Control
      • Phosphate Sequesterant Feed Control
      • Reservoir Monitoring
      • Security Monitoring
      • TOC Monitoring in Water
      • Well Blending
    • Wastewater Monitoring and Control >
      • Aeration Control and Energy Cost Reduction
      • Biological Nutrient Removal
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      • Chemical Phosphorus Removal
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      • Nitrification
      • Nutrient Deficiency Analysis
      • Lagoon Discharge
      • SBR Stage Control
      • TOC Monitoring
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      • mini oP (Ortho Phosphate)
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      • ChemScan 6101 Nutrient Control
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COD

Statement of the Problem

Organics Analysis Classifications

Organic compounds in water are present in a variety of particle sizes and oxidation states. Some of these carbonaceous compounds can be oxidized further by biological or chemical processes, with analytical methods such as the biochemical oxygen demand (BOD) or chemical oxygen demand (COD) used as the measurement standard.

Standard COD measurement techniques are the result of a complex series of laboratory procedures. Methods for analysis in the laboratory include various reflux methods which require careful reaction of a sample with potassium dichromate and sulfuric acid, capture of condensate and reaction with an indicator chemical. These methods are difficult to perform and extensive to automate.

ChemScan Analytical Method


On-line COD analysis using ultraviolet light absorbance can be performed using ChemScan Process Analyzers. The ChemScan UV-0254 provides a measurement of light absorbance that can be correlated with soluble COD after compensating for turbidity at a second wavelength. Other ChemScan analyzers provide a measurement of light intensity at 256 increments across the 200 nm to 450 nm wavelength range and can compensate for a wide variety of inorganic substances in the sample. Thus, a range of wavelengths can be used for the correlation calculation.

​Because no two chemical substances absorb light in exactly the same pattern over the same wavelength range, a multiple wavelength analysis can be used to accurately measure multiple constituents and to correlate dissolved organic measurements with COD values. The result is an estimation of COD using only light absorbance as the measurement technique. Visible wavelengths are used to compensate for turbidity variations in the sample. A branch of mathematical analysis known as “pattern recognition” is used to process the multiple wavelength light absorbance information and calculate the COD measurement.
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ChemScan, Inc.
2325 Parklawn Dr., Suite I, Waukesha, Wisconsin, USA 53186
​Phone: 262-717-9500
Toll Free: 800-665-7133
  • Applications
    • Municipal Water Monitoring >
      • Ammonia Feed
      • Chloramination Control
      • Chlorination
      • Color Analysis
      • Distribution Monitoring
      • Hardness Monitoring
      • Ion Exchange Breakthrough
      • Natural Organic Matter (NOM) Removal
      • Peak Point Chloramination Control
      • Phosphate Sequesterant Feed Control
      • Reservoir Monitoring
      • Security Monitoring
      • TOC Monitoring in Water
      • Well Blending
    • Wastewater Monitoring and Control >
      • Aeration Control and Energy Cost Reduction
      • Biological Nutrient Removal
      • Biological Phosphorus Removal
      • Chemical Phosphorus Removal
      • Chloramination /Breakpoint Avoidance
      • Chlorination/De-Chlorination
      • De-Nitrification Monitoring
      • Nitrification
      • Nutrient Deficiency Analysis
      • Lagoon Discharge
      • SBR Stage Control
      • TOC Monitoring
      • UV Disinfection Control
    • Industrial Water Treatment >
      • Boiler Water Analysis
      • Cooling Water Analysis (Closed Loop)
    • Industrial Process Monitoring >
      • Electroless Plating
    • ASA Technical Papers (ALL)
    • ChemScan Installation Photos
    • Success Stories
    • ChemScan Webinars
  • Service
    • Contact Service Request Form
    • ChemScan Service Team
    • MSDS
    • Communication Protocols
    • Software Utilities
    • Service Videos
  • Parts
  • Company
    • Terms and Conditions
    • Contact Form (General Inquiry)
    • Contact Service
    • Application Data Sheet
    • Employment Opportunities
    • Representatives and Distributors
  • Products
    • ChemScan Mini Analyzer >
      • mini oP (Ortho Phosphate)
      • mini oP (Ortho Phosphate) Extended Range
      • mini LoP (Low Ortho Phosphate)
      • mini UV-254
      • mini LowAm (Low Ammonia)
      • mini Mn (Manganese)
      • mini LowMn (Low Manganese)
      • mini LowChlor (Low Chlorine)
      • mini Sulfite
      • mini Mono (Monochloramine)
      • mini Ammonia
      • mini FreeAm (Free Ammonia)
      • mini Cu (Copper)
      • mini Low CrVI
      • mini Fe (Iron)
      • mini Ni (Nickel)
      • mini PAA (Peracetic Acid)
      • mini Silica
      • mini ChlorAm
    • ChemScan mini Accessories
    • ChemScan Process Analyzers >
      • ChemScan 2150/S Chloramination Analyzer
      • ChemScan 2150/DC Chem Feed Analyzer
      • ChemScan 2150/N Aeration Rate Analyzer
      • ChemScan 2150/NoP Chem Feed Analyzer
      • ChemScan 2150/NHoP Nutrient Analyzer
      • ChemScan 2150 Process Analyzer
      • ChemScan UV-3150 Process Analyzer
      • ChemScan 4100 Nutrient Control
      • ChemScan 6101 Nutrient Control
    • ChemScan Process Analyzers with HMI >
      • ChemScan 2250/S HMI Chloramination Analyzer
      • ChemScan 4200 HMI Analyzer
      • ChemScan 3250 HMI Analyzer
      • ChemScan 2250/NoP HMI Analyzer
      • ChemScan 2250/NHoP HMI Analyzer
      • ChemScan 2250/N HMI Analyzer
      • ChemScan 2250/DC HMI Analyzer
      • ChemScan 2250 HMI Analyzer
    • ChemScan Titrator/ISE Analyzer >
      • For Wastewater
      • For Water
    • ChemScan Analyzer Accessories
    • ChemScan Sensor Family