Design, manufacturing, commissioning and maintenance of a plant to recover a contamination hot spot.
The characterization of the site indicated a heavy contamination, in the shallow aquifer, of chlorinated solvents with the presence of DNAPL. The understanding led to the development of an empirical quantitative approach based on energy consumption, time frame recovery and costs. We demonstrated that the high concentration of chlorinated solvents could have been extracted and treated by implementing a catalytic oxidiser. Being solvents an inefficient source of energy, since their combustions values are very low reaching a temperature of 450 °C, it is possible to obtain a molecular oxidiser releasing however hydrochloric acid as a result of the oxidization.
The system was finally installed and it consisted of two catalytic oxidisers treating the gas from two SVE systems. Several pneumatic bottom inlet pumps were installed with an DNAPL separator in order to recover the free phase and an air stripper was installed.
At present, the system is recovering about 500 kg of solvents per day.
- 2 catalytic oxidizers each treating 500 m3/h
- 1 air stripper with a maximum treating flow of 10 m3/h
- 3 SVE systems each with a flow of 500 m3/h
The clean-up strategy has been successful, representing the final remediation target to be achievable by using specific technologies. In this project, a number of critical practical issues, such as soil saturation concentrations were analysed, taking into account the complexity of the actual situation. Geostream has shown capabilities, experience and tools to implement a complete project for the remediation, with specific references, of chlorinated solvents.