# A PHREEQC-Based Tool for Planning and Control of In Situ Chemical Oxidation Treatment
## 3 Results  
### Study Site and Injection Details  
The developed tool was tested in a hazardous materials warehouse in Flanders. The area was contaminated with chlorinated aliphatic hydrocarbons (CAH) and petroleum hydrocarbons (TPH). Sodium permanganate was used as an oxidising agent. The data for the study site, which were based on the laboratory and field tests, and information on the ISCO procedure are presented in Table 4. The test was conducted on a contaminated area with a radius of approximately 4 m and a depth of 8 m. The area included six monitoring wells and one injection site (Figure 2).  
The ISCO was preceded by two detailed sampling campaigns that included each monitoring well (4 months and 3 weeks prior to injection), followed by four campaigns (1 week, 3 weeks, 2 months, and 4 months post-injection). Meanwhile, each monitoring well was part of a real-time monitoring system that included the following data: pH, pE, temperature, and conductivity. During the full-scale test, 1200 L of 0.083% NaMnO4 were injected in 4.5 h with a MIP-IN probe, which is a combination of a MIP (membrane interface probe) and injection system, into a depth interval of 5.4-6.9 m bgl. The combined detection and injection system adjusts the volume and concentration of the injected fluid to the amounts of specific compounds detected in each 30 cm interval during drilling. Detection is based on the MIP-IN, which is integrated into a GC (gas chromatograph) equipped with an FID (flame ionisation detector), PID (photoionisation detector) and XSD (halogen specific detector). The geological screening revealed that the study area was not homogeneous in  
\begin{table}
\begin{tabular}{l l} \hline \hline  & **Contaminated Area** \\
**Parameter** & **Values*** \\ \hline Groundwater level & 1.33 \(\div\) 1.53 (avg. 1.45) m bgl. \\ pH & 6.4 \(\div\) 8.2 (avg. 7.41) \\ ORP & \(-\)286 \(\div\) 98 (avg. 35) mV \\ Dissolved oxygen & 1.3 \(\div\) 2.9 (avg. 2.16) mg/L \\ DOC & 75 \(\div\) 3710 (avg. 548) mg/L \\ Eh & \(-\)0.286 \(\div\) 0.098 (avg. \(-\)0.035) V \\ EC & 756 \(\div\) 5070 (avg. 1883) \(\mu\)S/cm \\ Groundwater temperature & 9.8 \(\div\) 13.5 (avg. 11.8) \({}^{\circ}\)C \\ Thickness of the contaminated & 1.5 m \\ layer & 1.5 m \\ Depth to the impervious layer & 25 m \\ Hydraulic conductivity & 7.25 \(\times\) 10\({}^{-8}\) \(\div\) 3.27 \(\times\) 10\({}^{-6}\) (avg. 9.4 \(\times\) 10\({}^{-7}\)) m/s \\ Porosity & 0.35 \\ Dry bulk density & 1700 kg/m\({}^{3}\) \\ Toluene & 0.014 \(\div\) 0.17 (avg. 0.037) mg/L \\ Ethylobenzene & 0.21 \(\div\) 6.8 (avg. 1.81) mg/L \\ Benzene & 0.02 \(\div\) 0.002 (avg. 0.013) mg/L \\ PCE & 0.05 mg/L \\ TCE & 0.05 mg/L \\ DCE & 0.05 \(\div\) 7.3 (avg. 1.26) mg/L \\ VC & 0.05 \(\div\) 0.32 (avg. 0.12) mg/L \\ NOD & 3792 mg/L \\ C-chlorides & 220 \(\div\) 1080 (avg. 391) mg/L \\ Parameter & Water in micropores & Clean Groundwater \\ Temperature & 14.7 \({}^{\circ}\)C & 12.7 \({}^{\circ}\)C \\ pH & 6.24 & 6.55 \\ Eh & 0.084 V & \(-\)0.061 V \\ Toluene & 0.8 mg/L & - \\ Ethylobenzene & 3.3 mg/L & - \\ Benzene & 0.05 mg/L & - \\ PCE & 1.7 mg/L & - \\ TCE & 0.4 mg/L & - \\ DCE & 10 mg/L & - \\ VC & 0.05 mg/L & 12.7 \({}^{\circ}\)C \\
**Injection Parameter** & **Values** \\ Volume of the injected fluid & 1.2 m\({}^{3}\) & \\ Concentration of the oxidant & 83 kg/m\({}^{3}\) & \\ pH of the injected fluid & 7 & \\ Pe of the injected fluid & 15 & \\ Velocity of the natural lateral & 20 m/year \\ flow & & \\ \hline \hline \end{tabular}  
*One value if based on one sampling or min \(\div\) max (and the distance averaged for the centre of the injection area) or if based on multiple monitoring wells.  
\end{table}
Table 4: Description of the test site parameters and ISCO procedure.  
terms of hydrogeological conductivity and that there were several impermeable soil layers within the aquifer that could serve as a barrier to the spread of the oxidant.