## 3 Results
### Microbiological Analysis Results  
MMM analysis results from each test cell are discussed below. Dairy Whey Test Cell (HSE-6/HSI-8): An analysis of HSE-6 groundwater samples showed a 1.5X order-of-magnitude (OM) increase in total population and a 4.5 XOM increase in sulfate-reducing bacteria (SRBs) following the dairy whey addition. A comparison of PLGA analysis results prior to and following whey addition also showed an OM increase in total biomass. The bacteria _Dehalococcus_ (DHC), an important genus known to completely reduce cVOCs to ethane [16; 17; 18; 19], increased 6X from baseline to 11 July 2007 (4.6 cells/mL vs. 27.3 cells/mL). The DHC population returned to baseline levels by the conclusion of the pilot test. The gene for the vinyl chloride reduction enzyme (vinyl chloride reductase (VC-RDase) and the gene for the TCE reduction enzyme (TCE-RDase) were not detected in baseline samples but were detected in samples collected after the dairy whey addition. EL Test Cell (HSE-11/HSI-14): Analysis HSE-11 groundwater samples showed a 1.5X OM increase in total population and a 6X OM increase in SRBs following the addition of EL  
Figure 8: Comprehensive test cell data summary: EVO + hydrogen gas, EW-3% VOC, and total VOC concentration. DHC population levels remained relatively unchanged in the EL test cell at less than ten cells per milliliter of groundwater. Additionally, an increased presence DHC was observed and VC-RDase was detectable after the addition of EL. A comparison of PLGA results prior to and following EL addition showed an order-of-magnitude increase in total biomass and an approximate 20% increase in _Firmicutes_ (fermenting bacteria). EVO Test Cell (HSE-14/HSI-19): Analysis of DNA extracted from HSE-14 groundwater samples showed a 1.5 XOM increase in total population and a 6.5 XOM increase in SRBs following the addition of EVO. The DHC population increased from non-detectable to approximately 100 cells per milliliter at the approximate midpoint of the test duration. By the end of the test the DHC population level dropped but remained detectable. Additionally, VC-RDase, which was not detected prior to EVO addition, was detected as part of the  
Figure 10: Comprehensive test cell data summary: EVO + hydrogen gas, SMW-35% VOC, and total VOC concentration. Figure 9: Comprehensive test cell data summary: EVO + hydrogen gas, IW-3D/IW-2D, IW-3D % VOC, and total VOC concentration. biorecirculation sampling. Comparison PLFA analysis results prior to and following EVO addition showed a 2 XOM increase in total biomass, and an approximate 15% increase in _Firmicutes._  
Source Zone EVO + Hydrogen Gas Infusion Test Cell (EW-3/IW-2S and IW-2D): Analysis of microbial DNA extracted from EW-3 groundwater samples showed a 2 XOM in total population and a 4.5 XOM increase in SRBs. The most encouraging aspects of the microbiological analysis were the changes in DHC. During the last three months of sampling (November 2007 through January 2008), DHC levels were observed to steadily increase from a background concentration of between 0.164 cells/milliliter and 9.98 cells/milliliter to 235 cells/milliliter. Comparison of PFLA results prior to and following EVO and hydrogen gas addition showed a 2.5 XOM increase in total biomass, and an approximate 3-fold increase in Firmicutes. Summary: The microbial consortia in the shallow aquifer was shown to contain the microbes (e.g., DHC) and the genes necessary for complete reductive dechlorination. Furthermore, EVO increased and supported respiration of cVOCs better when compared with the dairy whey and EL. MMM results tracked changes in the microbial consortium correlated to reductive chlorination. Select groundwater samples from the site were subjected to shotgun metagenomic analysis. Results from baseline to five months after the start of full-scale remedial action have already been published [20]. The MMM results in the present study are supported by the metagenomic analyses.