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Permeable biobarrier systems (PBSs) are being recognized as low-cost passive bioremediation technologies for chlorinated organic contamination. This innovative technology can play a crucial and effective role in site restorations. Laboratory-scale experiments were conducted to investigate the biodegradation of trichloroethylene (TCE) to ethylene in shallow groundwater through the use of a PBS enhanced by bioaugmentation at the U.S. Department of Energy's Savannah River Site (SRS). Two composts and two plant amendments, eucalyptus mulch (EM) and corncobs (CC), were examined for their effectiveness at creating and maintaining conditions suitable for TCE anaerobic dechlorination. These materials were evaluated for their (1) nutrient and organic carbon content, (2) TCE sorption characteristics, and (3) longevity of release of nutrients and soluble carbon in groundwater to support TCE dechlorination. Native bacteria in the columns had the ability to convert TCE to dichloroethenes (DCEs); however, the inoculation with the TCE-degrading culture greatly increased the rate of biodegradation. This caused a significant increase in by-product concentration, mostly in the form of DCEs and vinyl chloride (VC) followed by a slow degradation to ethylene. Of the tested amendments, eucalyptus mulch was the most effective at supporting the reductive dechlorination of TCE. Corncobs created a very acidic condition in the column that inhibited dechlorination. O

The objective of this study was to identify low-cost natural amendments that could be used as carbon sources and sustain a bioactive zone to promote biodegradation of TCE in contaminated shallow groundwater. The natural amendments were compared based on their geophysical characteristics as well as TCE adsorption capacities. The amendments studied included low-cost natural and agricultural materials such as eucalyptus tree mulch, pine bark mulch, muck from the Florida Everglades, SRS wetland peat, commercial compost, and peat humus. These natural substrates have relatively high organic fractions that can retard the movement of TCE while serving as carbon sources. Batch sorption studies were conducted to determine the sorption and retardation characteristics of the amendments for TCE. The experimental results were analyzed in relation to the geophysical characteristics of the amendments and compared with those of natural soils.

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The Town of Davie, FL, is evaluating the feasibility of an upgrade its System II Wastewater Treatment Plant (WWTP) with tertiary treatment to promote indirect potable reuse and obtain aquifer recharge credit in Broward County. Florida Department of Environmental Protection (FDEP) requires the evaluation and piloting of any advanced treatment technologies that plan to engage direct recharge to the Biscayne Aquifer. Chapter 62-610, Part V, F.A.C mandates the evaluation of such technologies via a pilot study to show the compliance of the reclaimed water with groundwater recharge standards.AECOM is currently conducting an advanced treatment pilot study for the Town consisting of Ultrafiltration (UF), Reverse Osmosis (RO) and Ultraviolet Light/Hydrogen Peroxide (UV/H 2 O 2 ) processes. This study is intended to evaluate the feasibility of this process for compliance with the FDEP and Broward County Environmental Protection Department (BCEPD) regulations for direct recharge to the Biscayne Aquifer.