A modified method for the determination of chemical oxygen demand (COD) for samples with high salinity and low organics.
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.
Vyrides
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Department of Chemical Engineering and Chemical Technology, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
Stuckey
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D000465:Algorithms; D002623:Chemistry Techniques, Analytical / Q000379:methods; D003198:Computer Simulation; D004784:Environmental Monitoring / Q000379:methods; D008956:Models, Chemical; D009930:Organic Chemicals / Q000032:analysis* / Q000737:chemistry*; D010100:Oxygen / Q000032:analysis* / Q000737:chemistry*; D054712:Salinity; D014874:Water Pollutants, Chemical / Q000032:analysis*
D009930:Organic Chemicals; D014874:Water Pollutants, Chemical; D010100:Oxygen