Polymer-Enhanced Remediation Techniques for More Effective Treatment of Heterogeneous Aquifers

In heterogeneous aquifers, permeability differences can channel injected remediation agents through preferential flowpaths. Because these flowpaths exist primarily in regions of high permeability, treatment agents may not contact contaminants trapped in lower-permeability zones. Introduction of a shear-thinning polymer may help to increase the delivery of the treatment agent by encouraging cross-flow throughout heterogeneous layers. Our research outlines feasible methods of combining polymer floods with existing remediation techniques (chemical oxidation and bioremediation) for more effective groundwater treatment. In earlier compatibility experiments, xanthan polymer demonstrated a stable solution viscosity and low nonproductive oxidant demand in the presence of potassium permanganate. The findings from column and two-dimensional tank experiments using this compatible polymer/oxidant mixture are presented with special regard to transport and implementation strategies. Results from both polymer-enhanced and aqueous-phase tank experiments are also compared in an effort to quantify the overall effectiveness of contaminant destruction of the two methods. In addition, the viability of polymer-enhanced bioremediation as demonstrated by microcosm testing using two types of non-toxic polymers is discussed. The implications of these experimental results for bioaugmentation or biostimulation are also presented.