Mass Transfer of MTBE in Groundwater During Air Sparging

摘要

A one-dimensional column is set up to study the mass transfer during air sparging process for methyl tertiary butyl ether (MTBE) removal in saturated soil and groundwater, with the condition of different airflow and soil penetrability. It is shown that the removal rate of MTBE can reach 80 percent, 90 percent and 95 percent when airflow is 0.05 m~3/h, 0.085 m~3/h and 0.10 m~3/h, respectively. Increasing airflow will help to increase the removal rate of dissolved MTBE, but eventually a threshold removal rate is reached, above which further increasing air injection rates does not increase the removal rate. Fine sand allows the injected air to travel in bubble form, while coarse sand and medium sand allow the injected air to travel in the form of discrete channels; the greater the soil grain size is, the more extensive the channel net work forms, which in turn leads to higher removal rate. A tailing effect of lingering residual contaminant concentrations occur within the fine sand. About 20 percent of MTBE cannot be removed.