Record Display for the EPA National Library Catalog


OLS Field Name OLS Field Data
Main Title Prediction of Phosphate Movement through Some Selected Soils.
Author Stuanes, A. O. ; Enfield, C. G. ;
CORP Author Norsk Inst. for Skogforskning, Aas.;Robert S. Kerr Environmental Research Lab., Ada, OK.
Year Published 1984
Report Number EPA/600/J-84/070;
Stock Number PB84-233253
Additional Subjects Water pollution control ; Water quality ; Industrial waste treatment ; Phosphoric acids ; Sorption ; Isotherms ; Transport properties ; Soils ; Kinetics ; Laboratory equipment ; Environmental surveys ; Design ; Reprints ; Land disposal
Library Call Number Additional Info Location Last
NTIS  PB84-233253 Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy. 06/23/1988
Collation 6p
The P sorption capacity of soils must be evaluated at land application wastewater sites when water quality criteria control the design of the treatment system. The soil's capacity to react with P is often underestimated when equilibrium isotherms are used to describe P sorption. An analytical one-dimensional convective disperive solute transport model, assuming linear sorption and first-order irreversible precipitation, was evaluated to describe the movement of P in small laboratory columns. The model was calibrated to experimental data using nonlinear least squares analysis. The length of the column did not make a significant difference in the model coefficients. This finding suggests that the approximation of a linear sorption isotherm with first-order irreversible precipitation is adequate for making environmental assessments at land-treatment systems. Application of the model to the design of a land-treatment system would permit approximating a system life considering wastewater application rate, concentration of P in the applied water, and travel distance through the soil profile prior to discharge. Experimental data fit to a Langmuir equation using the same soils were found to seriously underestimate the capacity of soil to react with P. The same data fit to a Freundlich or other equilibrium isotherm would yield similar results. It was concluded that use of equilibrium isotherms without considering the kinetics of the reactions will lead to overly conservative designs of land application of wastewater treatment systems.