Performance of polymer-enhanced KMnO4 delivery for remediation of TCE contaminated heterogeneous aquifer: A bench-scale visualization

Abstract

The uniform migration of remedial amendments in an aquifer was negatively influenced by medium heterogeneity and the density effect of amendment. This study sought to use a polymer (xanthan) to enhance the uniformity of amendment distribution in contamination zones. Visible tank experiments were conducted to investigate the feasibility and performance of xanthan-enhanced KMnO4 delivery in the simulated aquifer. The results showed that the addition of xanthan improved fluid movement into the lower-permeability stratum, so the overall sweeping efficiency was remarkably increased compared to the fluid control test without polymer using. In two layered aquifer systems, the smaller the thickness of the low-permeability layer is, or the greater the permeability contrast between layers is, the more obvious the enhancement of the uniform distribution of remedial fluid by xanthan. The sinking of KMnO4 solution in medium and coarse sand aquifers was obvious, and the effect of KMnO4 concentration and aquifer medium size on the density effect was evaluated. The fluid viscosity increase caused by xanthan addition could stabilize the displacement front and reduce the density effect. Xanthan-KMnO4 applications were more effective at penetrating finer-grained lenses and played a more obvious role in TCE oxidation removal.