An Experimental Study of Phytoremediation of Methyl-tert-butyl Ether (MTBE) in Groundwater

Abstract

The feasibility of phytoremediation of groundwater contamination with methyl-tert-butyl ether (MTBE) was examined experimentally using a six-channel soil system with or without plants. Two bacterial strains capable of degrading MTBE were each added to two out of six channels. A solution of 0.84 mM MTBE was continuously fed into each channel at 1 L/day until a stable MTBE concentration level in the groundwater was established; then the feeding was switched back to distilled water. The channel groundwater effluent MTBE concentration and the soil gas MTBE fluxes were monitored from the beginning of the MTBE solution feeding until no MTBE was detected. Integration of the gas flux data indicated that the four vegetated channels with introduced bacteria had less MTBE at the soil surface than channel 3 which was vegetated but without any introduced bacteria. The total mass balance for MTBE showed that the fractions of MTBE that were not recovered in the planted channels were significantly higher than in the unplanted channel. Analysis of the experimental data indicates that, due to the presence of the plants, MTBE might have been undergoing enhanced rhizosphere biodegradation. ABSTRACT

Uptake, metabolism, and toxicity of methyl tert-butyl ether (MTBE) in weeping willows

“…Zhang et al [33] used a six-channel system with alfalfa plants and found pronounced rhizosphere effects. Two bacterial strains capable of degrading MTBE were added to two channels.…”

Performance Evaluation Using a Three Compartment Mass Balance for the Removal of Volatile Organic Compounds in Pilot Scale Constructed Wetlands

“…4,11 The investigations contributed to transferral of the CW approach from small scale to field scale application. 12,13 Few studies have considered the flux of VOCs into the atmosphere for mass balancing based on experimental data 7,14 or simulations. 15 Recent wetland research also attempted to examine the role of plant uptake during VOC treatment.…”

Phytoremediation

“…10) by changing the water velocity (v z ) through transpiration. Studies report that transpiration contributes significantly to the transport of organic contaminants in soil [136,137].As plants take up water from the subsurface, the horizontal water recharge can lead to an increase in the advective transport (q z = v z q w ) of contaminants by increasing q w . However, also due to the plant transpiration, θ w will decrease, possibly causing the overall advection to decrease.…”