To date, more than 12.9 million gallons of petroleum products have been recovered and 3.5 billion gallons of water have been treated. ExxonMobil is committed to conducting a thorough and effective recovery, and continues to assess on a regular basis ways to enhance and optimize its recovery operation.
According to the 2007 U.S. Environmental Protection Agency Report, the dual-pump recovery is the most efficient and best sub-surface option for remediating the petroleum contamination underneath a section of Greenpoint. The system recovers product by depressing the water table around the recovery well to create a cone of depression which allows the petroleum products to flow into the recovery well. One pump in the recovery well removes the water, and the other pump removes petroleum products into storage tanks.
Groundwater removed by the dual-pump system is treated to remove contaminants, and tested to ensure its compliance with state and local regulations before being released into Newtown Creek.
- Water entering the system is held in a stabilization tank to allow it to settle.
- Air is injected into the water and passes it through filters that remove iron and magnesium.
- Petroleum components are removed from the groundwater by a process called air stripping. ExxonMobil’s process injects air through the water as it cascades down through a series of trays with holes of decreasing size that strip the contaminants from the water.
- Treated water is piped to one of two discharge points into Newtown Creek.
- During typical operation the recovery system pumps and treats up to 15 million gallons of groundwater each month.
- The discharged groundwater is sampled monthly and results are reported to the New York State Department of Environmental Conservation.