TIPOLOGY: Multi-Phase Extraction (MPE)
On this site, contamination impacted both the unsaturated zone and the groundwater.
The contamination consisted of petroleum hydrocarbons, aromatic solvents (BTEXs), isopropylbenzene (or cumene) and polycyclic aromatic hydrocarbons, with the presence of supernatant phase.
The installed system consists of 3 MPE modules, each designed to treat three phases: groundwater, any supernatant and interstitial soil gases with each plant extracting from 10 extraction wells.
Each well was equipped with a pump for extracting groundwater, a pump for recovering the product and a sealed wellhead for extracting interstitial gases from the ground by means of dedicated blowers. Electromagnetic meters (water), mass meters (product) and pressure gauges (gas) have been installed on each line.
The line dedicated to the extraction of liquids was connected to an oil/water separator equipped with radar sensors for the recognition of the level of supernatant and water. The water and the product are separated into two lines, one to the tank for aromatic organic substances for onsite disposal via the Client’s plant incinerator and the other, water line, to the groundwater treatment plant. In order to avoid explosion risks in the headspace of the separator, a pre-vacuum nitrogen treatment system has been installed. The water/tank for aromatic organic substances separation system phase is controlled by a PLC connected to the control cabin.
The gases extracted from the MPE system are passed through a thermal combustor with chamber temperatures of about 950 °C for complete contamination destruction.
All the systems featured automatic remote alarms and automatic plant shutdowns communicating with each other.