What is Chemical Oxygen Demand (COD)?
Chemical Oxygen Demand (COD) is a wastewater parameter that measures the amount of a specified oxidant after it reacts with organic matter under controlled conditions. A COD test typically involves digestion of a water sample in a sealed vial with potassium dichromate and sulfuric acid at 150oC for 2 hours.
Why test for COD?
Chemical oxygen demand measurements are used to estimate water pollution levels entering and leaving wastewater treatment and industrial facilities. In the United States, treatment facilities are considered point sources, making them regulated under the Clean Water Act (CWA) which in turn sets facility specific pollutant release targets as part of the National Pollutant Discharge Elimination System (NPDES) permitting process. These permits often specify limits based on the COD chemistry method of analysis.
Additionally, there is a connection between energy use at wastewater facilities and COD. Wastewater engineers can use COD as an indicator for how much oxygen will be required to treat incoming waste streams. This has a direct impact on aeration equipment power consumption. Having an understanding of COD trends allows engineers to optimize power usage and gain control of energy costs.
About our Test Kits
CHEMetrics offers two dichromate reactor digestion methods for fast, easy, safe determinations of low-, mid-, and high-range COD levels in wastewater: the USEPA-accepted Method* and a mercury-free method. The products using the USEPA-accepted method contain mercuric sulfate in the reagent to eliminate chloride interferences. The mercury-free product line is applicable when chloride interference is not a concern and USEPA reporting is not required.
Click here to see how our COD wastewater tests compare to competitors.
Click on a catalog number in the tables below for more information or to purchase a COD test kit.
|Range||Method||Kit Catalog No.||No. of Vials|
|0-150 ppm (LR) USEPA-accepted||Dichromate Reactor Digestion||K-7350S*||25|
|0-150 ppm (LR) USEPA-accepted||Dichromate Reactor Digestion||K-7355*||150|
|0-150 ppm (LR) Mercury-free||Dichromate Reactor Digestion||K-7351S||25|
|0-150 ppm (LR) Mercury-free||Dichromate Reactor Digestion||K-7356||150|
|0-1500 ppm (HR) USEPA-accepted||Dichromate Reactor Digestion||K-7360S*||25|
|0-1500 ppm (HR) USEPA-accepted||Dichromate Reactor Digestion||K-7365*||150|
|0-1500 ppm (HR) Mercury-free||Dichromate Reactor Digestion||K-7361S||25|
|0-1500 ppm (HR) Mercury-free||Dichromate Reactor Digestion||K-7366||150|
|0-15,000 ppm (HR+) Not USEPA Approved||Dichromate Reactor Digestion||K-7370S*||25|
|0-15,000 ppm (HR+) Not USEPA Approved||Dichromate Reactor Digestion||K-7375*||98|
|0-15,000 ppm (HR+) Mercury-free||Dichromate Reactor Digestion||K-7371S||25|
|0-15,000 ppm (HR+) Mercury-free||Dichromate Reactor Digestion||K-7376||98|
|Product||Kit Catalog No.|
|COD Calibration Standard, 1000 ppm||A-7301|
|COD Calibration Standard, 10,000 ppm||A-7310|
*Contains mercury. Dispose according to local, state or federal laws.
1 NOTE: No endorsement by Hach Company is implied or intended.