Soil and Groundwater Investigation
Service / Soil and Groundwater Investigation
FREEAIR has accumulated over 20 years of experience in Soil and Groundwater Investigation and has a corresponding high core competency. Our prolonged experience shows time and time again that an accurate investigation of the underground and the groundwater is a vital factor in planning further work on a project. Of especial importance is the preparation of a CSM which identifies the sources of any contamination, what these sources may affect (receptors) and how these products travel from the sources to the receptors (pathways).
◆Investigation and assessment of contaminated sites
◆Risk assessment for soil and groundwater
◆Remediation action investigations
◆Expert opinion and court-appointed expert opinions
◆Use of innovative investigation methods
◆Remediation planning/design and feasibility studies
◆Remediation supervision and monitoring
Jet-grouting with ISCO and P&T to Treat a Co-mingled DNAPLs and Fluoride Plume.
The investigation and remediation of a semiconductor company site at Tainan, the maximum concentration of TCE and Fluoride in groundwater prior to remediation was 2,500 ppb and 27,300 ppb, the texture and structure of the aquifer is mainly silt, and the hydraulic conductivity is about 10-4~10-3cm/s, whereas after applying jet-grouting/ISCO and pump-and-treat, TCE and Fluoride concentrations were below of 2 ppb and 100 ppb.
Remedial Action
Field Test:
Groundwater was treated using the P&T process from the 1st to the 210th day, that concentration for DNAPLs pollutants had decreased after 210 d of the P&T process. P&T can therefore effectively remediate various DNAPLs simultaneously. However, groundwater remediation is difficult because of the complexity of the treatment area and the presence of various pollutants, and it is difficult to achieve using a single process.
In this case, the P&T technique was used as the main treatment, and the Jet-grouting with ISCO technique was used to supplement the treatment and to complete the treatment of refractory pollutants.
Remediation:
6,000 m³ of contaminated groundwater was pumped and processed by air stripping and activated carbon filters to remove volatile organic compounds. Partial areas where cannot be effectively pumped, we use Immobilization and ISCO to treat with fluoride and DNAPLs respectively.
