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APHA
SMWW 5220
Chemical Oxygen Demand (COD)
2023
6
Standard methods for the examination of water and wastewater (543.3 APHA 24th ed. Ref. Treatises&monographs FL2)
Chemical oxygen demand (COD) is defined as the amount of a specified oxidant that reacts with the sample under controlled conditions. The quantity of oxidant consumed is expressed in terms of its oxygen equivalence. Because of its unique chemical properties, the dichromate ion (Cr2O7 2-) is the specified oxidant in Methods 5220 B, C, and D; it is reduced to the chromic ion (Cr3+) in these tests...