Oxygen reaeration rate constant

The environmental oxygen reaeration rate constants ( °)env are available for representative bodies of water in Mill, et al. 

The estimated oxygen reaeration rate constant is related to the dissolved oxygen concentration measurements and time by the following regression equations ... 

In general, the volatilization rate, iJy, is a first-order kinetic process (Appendix D-4 Liss and Slater, 1974 Mackay and Leinonen, 1975). For hi ly volatile compounds and for Henry s law constant He > 3000 torr volatilization rate is determined by the diffusion through the liquid-phase boundary layer (Appendix D-5). In cases where He < 0 torr M , the diffusion through the gas-phase boundary layer limits the volatilization rate. For conditions between 3000 and 10 torr both liquid and gas phase are significant. In these cases, the mass transport coefficients of the chemical in the water column are estimated from representative values of mass transport coefficient for oxygen reaeration and water where liquid-phase resistance and gas-phase resistance are controlled, respectively. 

Under equiUbrium or near-equiUbrium conditions, the distribution of volatile species between gas and water phases can be described in terms of Henry s law. The rate of transfer of a compound across the water-gas phase boundary can be characterized by a mass-transfer coefficient and the activity gradient at the air—water interface. In addition, these substance-specific coefficients depend on the turbulence, interfacial area, and other conditions of the aquatic systems. They may be related to the exchange constant of oxygen as a reference substance for a system-independent parameter reaeration coefficients are often known for individual rivers and lakes. 

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