Notice:

As of January 16, 2023, pricing changes have taken effect. Please see our Pricing Change Information for details.

OWP will be closed from Friday, December 22, 2023, through Monday, January 1, 2024, for Winter Break.

If exams are submitted: Course certificates will be mailed:
Before December 19 Before December 23

After December 19 Early January

If exams are submitted:	Course certificates will be mailed:
Before December 19	Before December 23
After December 19	Early January

Water and Wastewater Terms Beginning C

A B C D E F G H I J K L M N O P Q R S T U V W Y Z

COD (pronounce as separate letters)

A measure of the oxygen-consuming capacity of organic matter present in wastewater. Chemical oxygen demand is expressed as the amount of oxygen consumed from a chemical oxidant in mg/L during a specific test. Results are not necessarily related to the BOD (biochemical oxygen demand) because the chemical oxidant may react with substances that bacteria do not stabilize.