Estimation of Sequential Degradation Rate Coefficients for Chlorinated Ethenes

Abstract

A sequential anaerobic-aerobic bioremediation pilot test was performed to assess its viability for chlorinated ethenes and to determine scaling parameters for remedial design. Transect data were evaluated to determine the first-order degradation rate of trichloroethene (TCE). Because the Damkohler numbers were greater than unity, a single-well regression approach was used to estimate the sequential first-order degradation rates. The biostimulated degradation kinetics were influenced by competing electron acceptors and total organic carbon. First-order degradation kinetics were appropriate after the biomass population was stimulated and critical redox conditions were established. First-order degradation rate coefficients ( λ ) were calculated for the anaerobic and aerobic degradation of TCE, cis-1,2-dichloroethene (cDCE), and vinyl chloride (VC) using regression analyses from predominant daughter products. In anaerobic groundwater, λTCE =0.084 days−1 , λcDCE =0.037 days−1 , and λVC =0.046 days−1 adjacent t...