PRBs, also known as treatment walls, are installed across the flow path of a contaminated plume and often keyed into lower permeability material.
Water flows through the wall while contaminants are degraded or retained in place.
The chromium originated from an electroplating shop that operated for more than 30 years before closing in 1984. TCE came from several sources, including the shop. At the time it was constructed, the USCG PRB was the longest PRB on record. The wall is about 150 long and 2 feet thick, begins about 3 feet below ground surface, and extends to a depth of 24 feet. It was installed more rapidly and inexpensively by using an innovative trenching technique.