Virginia Institute of Marine Science
Proceedings National Shellfisheries Association
Two equations can be written to describe the change in bacterial concentrations in the shellfish and the water in depuration units. Analytical solutions of these equations for special conditions and numerical solutions for general conditions indicate that there will always be an initial, rapid decrease in bacteria in the oysters during depuration. With suitable flow rates and loading rates, the die off will be exponential and several orders of magnitude reduction can be achieved within 72 hours. Both very low flow rates and very low loading rates increase the residence time of water in the tank, and therefore depuration will occur slowly after about 24 hours. In addition, the bacterial levels at 72 hours may be quite high for the case of very low flow rates. Further improvements and verification of the model are desired, but use of the model can aid in the design and operation of depuration plants now.
Contribution (Virginia Institute of Marine Science) no. 748
Neilson, Bruce J., A mathematical approach to depuration (1976). Proceedings National Shellfisheries Association, 66, 76-80.