Behavior of Organic Pollutants During Rapid-Infiltration of Wastewater Into Soil: I. Processes,Definition,and Characterization Using a Microcosm

Abstract

ABSTRACT

A microcosm was constructed to study the behavior of organic pollutants during rapid infiltration of municipal wastewater into soil. The microcosm permitted a direct measure of the amount of volatilization and allowed calculation of the amount that degraded. The microcosms received 4.4 ± 0.2 cm of wastewater each day; an application was made every four hours. The wastewater was amended with selected organic compounds at individual average concentrations of 0.2 to 32 μmol/L. Chloroform, 1,1-dichloroethane, 1,1,1-trichloroethane, trichloroethene, and tetrachloroethene volatilized extensively. Individual average concentrations in the microcosm effluent ranged from 9 ± 5% to 27 ± 11% of the applied concentrations. There was observable degradation of 1,1-dichloroethane but there was no detectable degradation of the other volatile compounds. Small proportions of chlorobenzene, 1,2-dichlorobenzene, and toluene volatilized; the remaining portion was extensively degraded, producing concentrations in the volume effluent of 9 ± 10% of the influent concentration or less. The concentration of 1,2,4-trichlorobenzene in the column effluent was <0.7% of that applied. The proportion that volatilized was not measured. Degradation was extensive for nitrobenzene, phenol, 2-chlorophenol, 2,4-dichlorophenol, and 2,4,6-trichlorophenol; concentrations in the column effluent were <0.2% of applied concentrations. The behavior of toluene and tetrachlorethene at ambient concentrations in wastewater (0.09 and 0.3 μmol/L) was similar to their behavior at amended concentrations.