Brief

At an active bulk fuel storage facility outside a city located in Northwestern Saudi Arabia, on the coast of the Red Sea, historical spills and leaks had resulted in the accumulation of up to 1.5m of gasoline in an unconfined, highly saline aquifer. Tidally influenced, the water table levels fluctuated up to 0.5m per day. The location of the impacts required a secure, explosion-proof, low-impact solution that could accommodate tidal water table fluctuations, withstand salt corrosion, and function without interfering with the facility’s daily operations.

Process

To capture and recover the gasoline from the surface of the water table, IRSL and their partner installed specialized pneumatic skimmers within 10 wells, in an area extending approximately 60m2. The chosen system was based on a series of tests, including NAPL transmissivity tests, in select wells. They enhanced the recovery of LNAPL from each 10cm diameter well using a low-vacuum system, which increased both the rate of recovery and area of influence.

Results

As a result of continuous optimization, the percentage of gasoline within the fluid recovered has been greater than 99.999% over the recovery period.

The NAPL plume has been contained and over 60,000L of gasoline have been recovered from a 100m2 area in less than four years.

Free product thickness in monitoring wells has decreased by over 75%.

System operation and maintenance costs have decreased relative to inflation over time.

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