SITE: about 2 km from the historical centre of Milan.
TYPOLOGY: Soil Vapour Extraction (SVE), Bio Venting (BV), and hydraulic barrier with rejection
Geostream installed an SVE/BV plant in a residential area at about 2 km from the historical centre of Milan.
The area is affected by aromatic hydrocarbon contamination, both in unsaturated soil adsorption phase and in dissolved phase in groundwater.
The SVE system included an automatic vapour extraction plant from unsaturated soil, installed in a 10′ container and connected to 9 vapour collection wells. The container housed the electrical panel equipped with PLC, 2 blowers equipped with inverters and having a capacity of 900 mc/h, the measurement and control instrumentation and a phase separator. The vapours extracted from the subsoil were treated using two active carbon filters.
It was possible to automatically change the operating mode from SVE to BV, i.e. blowing ambient air into the subsoil to promote aerobic biodegradation of contaminants.
The SVE/BV system has been subsequently integrated with a treatment plant for water discharged from 2 barrier wells, equipped with a system of re-injection of treated water back into the groundwater, through 2 wells.
The additional plant is supplied by the electrical panel of the SVE/BV system and consists of a quartzite particulate filter and an activated carbon filter. Treated water is reintroduced into the water table through 2 re-injection wells, under control of solenoid valves able to automatically close the re-injection lines and temporarily stop the barrier well pumps if the emitted flow rate exceeds that of re-injection.