Evaluation of groundwater remediation strategies at petroleum contaminated sites based on groundwater modelling approach

Based on the hydrogeological survey and groundwater environmental investigation at an abandoned oil refinement factory, a site-specific groundwater flow and solute transport model was constructed to support the development of groundwater remediation strategy. The contamination plume of Benzene is simulated and predicted in 30-year scale for designed scenarios. The results indicate that the groundwater quality takes long time to recover even though the contamination source above the water table is cleaned up. This is due to the large quantity of solved contaminants in local aquifer, and additionally the contribution from groundwater circulation is limited. The groundwater remediation actions, such as Pump & Treat (P&T) and In-Situ Chemical Oxidation (ISCO) could greatly improve the groundwater quality. However, under the site-specific circumstance, the ISCO technique is efficient but costly; the P&T takes longer time but more flexible and effective in protecting target drinking wells. Therefore, a combined remediation approach including both P&T and ISCO would be recommended. In summary, by the quantitative analysis regarding the feasibility, time scale, and effectiveness for the potential applicable remediation approaches, the groundwater modelling framework provided a insight on the system behavior and reliable support for the decision making in groundwater protection. (paper)