Interim Measure Remedies

Interim Measure Remedy Evaluation

Calumet Montana Refinery (CMR) conducted a Truck Loading Rack Interim Measure remedy evaluation during the spring of 2019. The remedial action goals identified for the Truck Loading Rack include:

Reduction of mobile light non-aqueous phase liquid (LNAPL) from the Truck Loading Rack source area.

Mitigate dissolved phase petroleum constituents from migrating offsite south from the Truck Loading Rack source area.

Contain dissolved phase petroleum constituents present along the north side of River Road from migrating further south.

CMR submitted the Truck Loading Rack remedy evaluation to Montana Department of Environmental Quality (MDEQ) on June 10, 2019.

Selected Interim Measure Remedies

The source and downgradient Interim Measure selected remedies address Truck Loading Rack historic petroleum release impacts.

Source Area Interim Measure remedial approach will include dual phase extraction (DPE) trench along the Truck Loading Rack's southern flank. The DPE system is intended to recover contaminant mass associated with free-phase LNAPL, to reduce the extent of LNAPL, and to stabilize the dissolved phase plume emanating from the LNAPL.

North River Road Area remedial approach will include a LNAPL recovery trench and a passive treatment trench (PTT). The LNAPL recovery trench and PTT are intended to mitigate dissolved phase groundwater impacts from migrating further south.

Completed Activities

CMR conducted the following activities to implement the Truck Loading Rack Interim Measure remedy:

Conducted preconstruction activities such as permitting, procurement, and contracting (December 2020 - May 2021).

Installed the Interim Measure remedies (May 2021 - October 2021).

Start-up and commissioning of the dual-phase interim measure remedy (October 2021 - December 2021).

Initiated LNAPL monitoring and recovery in the LNAPL trench (October 2021 - December 2021).

South side of the DPE System Enclosure. Self-Recuperative Catalytic Oxidizer (SRCO) Unit shown on right

Installation of product recovery trench

Final grade with a layer of seeding and hydromultch at DPE wells

DPE system enclosure interior (Vacuum Blower on left and vapor/liquid separator tank on right)

DPE System Enclosure (on right) and Self-Recuperative Catalytic Oxidizer (SRCO) Unit (on left)

Completed product recovery trench and PTT

Future Activities

CMR will conduct the following activities to implement the Truck Loading Rack Interim Measure remedy:

Operation, maintenance, and monitoring of the dual phase extraction system.

Quarterly reporting.

Optimization of LNAPL recovery in the LNAPL recovery trench.