Microbial barriers to the spread of pollution

Abstract

Contamination of groundwater with toxic and carcinogenic compounds is a serious concern for public health and environmental quality. This problem is commonly manifested as a contaminant plume migrating in the direction of groundwater flow from a point source. Containment of the contaminant plume is important for preventing further migration and localizing the plume for in situ or ex situ remediation. Current containment methods include sheet pilings and grout curtains. These abiotic barriers require extensive physical manipulation of the site (e.g. excavation and back-filling) and are expensive to construct. An alternative approach, biobarrier technology, involves the use of microbial biomass produced in situ to manipulate groundwater flow (Figure 1). Biobarriers promise to be more cost effective and cause less surface disruption then conventional barrier technologies. Furthermore, containment using biobarriers can be combined with in situ biodegradation or biosequestration. This chapter will review published research that relates to biobarrier formation and present results from a mesocosm test of biobarrier longevity. These results demonstrate the effectiveness of microbial barriers for manipulation of hydraulics in mesoscale porous medium reactors.