BOD & COD in Effluent of Pulp and Paper Mills
By Sara Mortenson (revised by Megan Webster and Stefanie Vagianos)
Biochemical Oxygen Demand (BOD)
Background
The majority of BOD is generated in the pulping and bleaching operations and is in the form of organic and inorganic solids
Biochemical Oxygen Demand is the amount of oxygen necessary for bacteria to consume the organic material in water.
The BOD test's most widely used application is in measuring waste loadings to treatment plants and for evaluating the efficiency of the treatment.
Testing for BOD
1. Measured amounts of wastewater (depending upon assumed BOD strength) plus dilution water (containing phosphate buffer, magnesium sulfate, calcium chloride, saturated with dissolved oxygen) are added to a 300ml BOD bottle.
2. The wastewater supplies the organic matter and the dilution water provides the dissolved oxygen. The general overall reaction for metabolism is:
3. Standard testing time is five days of incubation at 20 degrees C. The dissolved oxygen is depletion in the test bottle is directly related to amount of degradable organics. For more specific details on BOD and the analysis see the page on BOD.