In Situ treatment of toluene in groundwater, Helsingborg, Sweden
Working with multiple stakeholders to complete chemical oxidation and enhanced aerobic bioremediation works
Multiple historic leakages from stored chemicals on an industrial site led to hydrocarbon contamination of the underlying groundwater, predominantly with toluene. Multiple site investigations indicated that the plume had migrated beyond the site boundary and into land owned by the neighbouring harbour authorities. An initial treatment comprised a pump and treat system which had successfully recovered 14m3 of toluene. However, the contaminant concentrations exceeded the legal limits for less sensitive or industrial land use (Swedish MKM values). Therefore, additional remediation phases were required to address the residual dissolved phase. An in situ remedial approach was chosen, using RegenOx and ORC Advanced.
Access for the injection works was limited to two areas: one on the original industrial site, and the other in the harbour downgradient. Both areas comprised operation industrial facilities and were separated by a public road and a railway line associated with the harbour.
Initial pilot trials were completed to assess which treatment options would be most effective for the site. The results demonstrated that RegenOx was the most suitable oxidant to address the elevated sorbed-phase and high concentrations of dissolved phase contamination. In the full-scale works, RegenOx was combined with ORC Advanced. ORC Advanced provides a constant supply of dissolved oxygen to enhance aerobic biodegradation, in order to further reduce dissolved phase contaminant concentrations below the target criteria.
- Pilot trials were used to determine the best remediation options for full-scale works.
- Engagement with multiple stakeholders to complete remediation of a toluene plume extending over several site boundaries.
- In Situ injection works were completed on two separate industrial facilities without disturbance to their operations.