Historical Contamination Liability
Historical infilling of a river channel with refinery wastes, including tars, presented a significant barrier to the regeneration of a former industrial facility and gasworks site.
The tars present within made ground deposits and contamination associated with other industrial processes formed two plumes within the groundwater, which regulators were concerned presented a serious threat to nearby controlled waters.
Integrated Treatment Design
A remediation strategy was designed to achieve:
- Stabilisation of tars in the source zone,
- Contaminated plume treatment,
- Reuse of treated materials onsite,
- Mitigation of environmental risks.
To provide the Client, Consultant and Regulator confidence in the solution, pilot testing was undertaken to determine the ideal stabilisation mix and most suitable oxidant.
- Circa 18,000m3 of tar contaminated soils were stabilised to form a development sub base for regeneration of the site.
- Dissolved contaminants, forming two plumes in the underlying gravel aquifer were treated with circa 3,000m3 of activated chemical oxidants across a four week period.
- Contaminated water from construction and remediation excavations was treated onsite.
- No soils left site as part of the remediation works.
- Water used in the chemical oxidation was sourced onsite from a deep abstraction borehole.
The treatment programme demonstrated that all remedial objectives had been achieved within 6 months.
Phased treatment ensures that development could commence in key areas within 3 months.