Contamination, Delineation and RemediationNatural Gas Refining Facility, UK

OIL & GAS

Ref: PS0014

Project Summary Contamination, Delineation and RemediationNatural Gas Refining Facility, UK

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Key Project Elements

• Regular Groundwater Quality Monitoring

• Risk Assessment

• Remedial Options Appraisal

• Remedial Design and Implementation

• Regulatory Support

CRA is providing a range of consultancy services to a gas refining installation in the UK, including the regular monitoring of soil and groundwater quality to satisfy the conditions of the installation’s Environmental Permit. The regular monitoring is undertaken to provide a warning of impact to the environment from the processes carried out at the installation. During a regular groundwater monitoring round, a layer of free-phase petroleum hydrocarbon was encountered in one of the wells at the installation. This prompted further investigation to identify the source of the contamination and to determine if it was a result of historical or current processes. This investigation involved laboratory analysis of the free-product to determine its composition, a study of the processes in the area that could potentially cause the contamination, and further intrusive investigation to delineate the extent of the contamination. CRA also worked closely with the client to determine the implications of the contamination with regards to Environmental Liability and their Environmental Permit. The investigations identified that the source of the contamination was a result of historical processes in a building adjacent to the location of the well. It was also determined that the free-phase contamination did not extend laterally into the wider area beyond the impacted well. A detailed quantitative risk assessment using ConSim fate and transport modelling software was undertaken to determine whether the resulting dissolved phase plume posed a risk to the environment. The risk assessment identified that the contamination did not pose a significant risk to identified receptors; however, due to the presence of free-phase hydrocarbon, CRA recommended as a proactive approach, that remedial works be undertaken to mitigate potential future issues. CRA undertook a remedial options appraisal to identify the optimal remedial method to be undertaken. CRA then designed, installed and implemented a pump and treat system targeting the free-phase petroleum hydrocarbon. Throughout the project CRA provided support to the client with regards to Regulatory liaison.