Modeling Chlorinated Ethene Removal in the Methanogenic Zone of Constructed Wetlands: A System Dynamics Approach

摘要

The purpose of this study is to gain understanding of the dynamics of the processes that degrade Perchloroethene (PCE) to ethene, within the confines of the methanogenic zone of a constructed wetland. A system dynamics modeling approach is used. This model is focused on determining conditions that will enhance contaminant degradation. The chemical and biological processes within the methanogenic zone of a wetland system are extremely complex and dynamic processes. The model is broken up into three simultaneous processes: dechlorination, methanogenesis, and fermentation. The system behavior of the methanogenic zone can be adequately described by the classical formulations of representative microbial reactions acting simultaneously within each process in response to substrate limitation. The zone is assumed to be homogeneous and well mixed. This study provides a fundamental understanding of the complex interactions within the methanogenic zone of a constructed wetland and gives some insight for implementation. Testing identified flow rate, hydrogen concentration, and initial PCE biomass as specific parameters, which could be optimized to have the most effect on contaminant fate.