## 2 Materials and Methods
### Pilot Test Procedures
#### 2.3.2 Biorecirculation Testing
Therefore, without separating the injection well into two separate and isolated screen sections, amendments and nutrients injected into a single well would have been disproportionately administered to areas of higher permeability which did not coincide with the highest levels of contamination. In this source zone test cell, electron donor addition occurred in two separate periods. The recirculation of the first period was three months, and the second period was one \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Test Cell Name** & **Ethyl Lactate Test** & **EVO Test** & **Dairy Whey Test** & **Source Zone Test** \\ \hline
**Well Pair** & HIS-14/HSE-11 & HIS-19/HSE-14 & HIS-8/HSE-6 & IW-2S/IW-2D/EW-3 \\ \hline
**Target Zone** & Hot Spot & Hot Spot & Hot Spot & Source Zone \\ \hline
**Electron Donor** & Ethyl Lactate & EVO & Dairy Whey & EVO \\ \hline \hline _Date_ & 6/12/2007 & 6/12/2007 & 6/20/2007 & 7/5/2007@IW-2D \\ \hline _Amount_ & 1457.38 L (385 gal) & 1381.68 L (365 gal) & 997.90 kg (2200 lb) & 1249.19 L (330 gal) \\ \hline _Nutrient Mix_ & 246.05 L (65 gal) & 283.91 L (75 gal) & 283.91 L (75 gal) & 227.13 L (60 gal) \\ \hline _Rate_ & 2.68 lpm (4.7 gpm) & 15.14 lpm (4 gpm) & 9.46 lpm (2.5 gpm) & \\ \hline
**Recirculation Time** & 2 weeks & 5 month & 15 days & 81 days \\ \hline
**Supplement EVO** & YES & YES & YES \\ \hline _Date_ & 10/12/2007 & 10/11/2007 & 10/15/2007 & 10/18/2007 \\ \hline _Amount_ & 946.35 L (250 gal) & 946.35 L (250 gal) & 946.35 L (250 gal) & 832.79 L (220 gal) \\ \hline _Injection Period_ & 6 h & 6 h & 5 h \\ \hline _Nutrient Mix_ & 227.13 L (60 gal) & 227.13 L (60 gal) & 227.13 L (60 gal) & 227.13 L (60 gal) \\ \hline _Injection Period_ & 2 h & 2 h & 2 h \\ \hline
**Sampled Well** & HSE-11 & HSE-14 & HSE-6 & EW-3 \\ \hline
**VOC Analysis** & cVOC, EPA 8260 & cVOC, EPA 8260 & cVOC, EPA 8260 & cVOC, EPA 8260 \\
**Performed and Methods** & TOC, EPA 9060 & TOC, EPA 9060 & TOC, EPA 9060 & TOC, EPA 9060 \\ \hline
**\# of VOC Samples** & 32 & 32 & 32 & 27 \\ \hline \hline \multirow{6}{*}{**MMM Analysis**} & Total Biomass & Total Biomass, PLFA & Total Biomass, PLFA & Total Biomass, PLFA \\  & Taxonomic ID with & Taxonomic ID with & Taxonomic ID with & Taxonomic ID with \\  & PLFA & PLFA & PLFA & PLFA \\ \cline{1-1}
**Perromed and Methods** & SRBs, CENSUS(qPCR) & SRBs, CENSUS(qPCR) & SRBs, CENSUS(qPCR) & SRBs, CENSUS(qPCR) \\ \cline{1-1}  & DHC, CENSUS (qPCR) & DHC, CENSUS (qPCR) & DHC, CENSUS (qPCR) & DHC, CENSUS (qPCR) \\ \cline{1-1}  & Functional Genes & Functional Genes & Functional Genes \\ \cline{1-1}  & CENSUS (qPCR) & CENSUS (qPCR) & CENSUS (qPCR) \\ \hline
**\# of MMM** & & & & \\
**Samples** & 6 & 6 & 6 \\ \hline
**Analytical Result** & Figure 5 & Figure 6 & Figure 7 & Figures 8–11 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Summary of electron donor addition, sampling analysis, and method details by test cell. month. For the first period, infusion of hydrogen gas was initiated with recirculation prior to amendment injection. After 20 days of hydrogen gas infusion, the EVO/nutrient mix was injected in a fashion as described earlier. Approximately 1249.2 L (330 gallons) of EVO solution and 227.1 L (60 gallons) of nutrient mix were injected as a solution through IW-2S and IW-2D (the shallow and deep injection wells). The second period started with a supplemental dose of nutrient mixture and was followed by injection of EVO. Each of IW-2S and IW-2D received approximately 832.8 L (220 gallons) of EVO injected over a 5.0 h period and 227.1 L (60 gallons) of nutrient mix injected over a 2.0 h period. Recirculation followed the direct injection of EVO and nutrient solution. Dairy Whey Test Cell (HSI-8/HSE-6): A portion of the dairy whey amendment was metered into the recirculation flow; however, due to a malfunction of the chemical metering equipment the recirculation flow was temporarily stopped, and most of the dairy whey amendment was directly injected into injection well HSI-8.