Mass flux behaviour of DNAPL sources after insitu surfactant flushing remediation

Past field studies have shown that complete removal of DNAPL by insitu remediation technologies is not possible in most cases. Accepting such limitations, there is a need to evaluate the risk of groundwater contamination after source remediation. To perform the evaluation, the mass transfer processes on DNAPL sources, which have undergone remediation must be known. It is considered that a better control of mass flux coming out of the remediated source zone leads to a better plume management including natural attenuation processes. The mass transfer processes are governed by various factors such as source geometry and morphology, NAPL saturation, and groundwater condition including local flow around the source zone. In this study, both soil column and tank experiments were conducted to quantify the dissolution behaviour of residual DNAPL sources of different geometries. Different levels of source zone removal were achieved by flushing surfactants in stages and the mass fluxes generated from the sources were measured at each stage of remediation. The experimental results show that the decrease in mass flux values are not proportional to the degree of DNAPL removal and the relative importance of source zone geometry and local groundwater flow condition on mass flux values is highlighted.

• INTRODUCTION

• EXPERIMENTAL DETAILS

• RESULTS AND DISCUSSION

• CONCLUSIONS

• ACKNOWLEDGEMENT

• REFERENCES