A modified method for the determination of chemical oxygen demand (COD) for samples with high salinity and low organics

Bioresour Technol. 2009 Jan;100(2):979-82. doi: 10.1016/j.biortech.2008.06.038. Epub 2008 Aug 9.

Abstract

This study proposes a modification to the standard method for the determination of the chemical oxygen demand of samples with a salinity up to 40 g NaCl/L and low organic concentrations (20-230 mg COD/L). The masking of chloride by the use of a HgSO(4):Cl ratio of 20:1 prior to digestion, and the use of 3g K(2)Cr(2)O(7)/L in the digestion solution resulted in an error of less than 10% and 12% for samples containing 40 g NaCl/L at 20-190 mg COD/L and 230 mg COD/L, respectively. Comparison of the standard method with the new proposed method using a synthetic sewage highlights the large errors (50-85%) of the standard method in contrast to an error of less than 10% for the proposed modified method.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms*
  • Chemistry Techniques, Analytical / methods
  • Computer Simulation
  • Environmental Monitoring / methods
  • Models, Chemical
  • Organic Chemicals / analysis*
  • Organic Chemicals / chemistry*
  • Oxygen / analysis*
  • Oxygen / chemistry*
  • Salinity*
  • Water Pollutants, Chemical / analysis*

Substances

  • Organic Chemicals
  • Water Pollutants, Chemical
  • Oxygen