is expressed in milligrams per liter (mg/L) also referred to as ppm (parts per
million), which indicates the mass of oxygen consumed per liter
Chemical Oxygen Demand (COD) test uses a strong chemical oxidant in an acid
solution and heat to oxidize organic carbon to CO2 and H2O.
demand is determined by measuring the amount of oxidant consumed using
titrimetric or photometric methods.
The test is not adversely affected by toxic substances, and test
data is available in 1-1/2 to 3 hours, providing faster water quality
assessment and process control.
Typical DIgestion Curves - COD vs.
COD determinations made for process control purposes can be conducted in a
shorter digestion time than specified in the procedure. For samples which are
difficult to oxidize, the digestion time can be extended up to four hours if a
blank is also run for the same period of time.
For more information