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|Title:||Assessment of the treatability of toxic organics by overland flow|
|Authors:||United States. Environmental Protection Agency.|
Jenkins, Thomas F.
Leggett, Daniel C.
Parker, L. V. (Louise V.)
Oliphant, Joseph L.
Martel, Courtland James.
Foley, B. T. (Brian T.)
Diener, C. J. (Carl J.)
|Publisher:||Cold Regions Research and Engineering Laboratory (U.S.)|
Engineer Research and Development Center (U.S.)
|Series/Report no.:||CRREL report ; 83-3.|
Abstract: The removal efficiency for 13 trace organics in wastewater was studied on an outdoor, prototype overland flow land treatment system. The removal for each of these substances was greater than 94% at an application rate of 0.4 cm/hr (0.12 m^3/hr·m of width). The percent removals declined as application rates were increased. The rate of removal from solution was described by the sum of two mass-transport-limited, first-order rate coefficients representing volatilization and sorption. A model based on the two-film theory was developed; the observed removal rate coefficients were regressed against three properties of each substance: the Henry's constant, the octanol-water partition coefficient and the molecular weight. The dependence of the removal process on temperature was studied and is included along with average water depth in the model. The decrease in removal rate as temperature declined is supported by the known dependence of Henry's constant and diffusivity on temperature. The model was validated on a second overland flow system. The surface soil concentrations of the trace organics determined at the end of the experiment suggest that a secondary mechanism renews the surface activity rapidly enough so that contaminants do not build up on the surface, with the possible exception of PCB. Biodegradation is suggested as the predominant secondary mechanism rather than volatilization because substances less volatile than PCB were not found at the end of the experiment.
|Rights:||Approved for public release; distribution is unlimited.|
|Appears in Collections:||CRREL Report|
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