LERF Basin 41

Description

In support of the Direct-Feed Low Activity Waste Program, part of the Hanford clean-up mission, Elite is responsible for the construction of a new 8-million-gallon hazardous wastewater retention basin, known as Basin 41, at the Liquid Effluent Retention Facility (LERF) at the Hanford site.

The project scope consists of civil and earthwork improvements to an existing 30-foot-deep depression in the vicinity of other LERF Basins created in the 1990’s. Workers excavated and removed thousands of yards of rubble and earth to create the profile required in import and place a 3-foot-thick layer of engineered soil and bentonite clay mix. A 360° concrete anchor wall was placed so specialty subcontractors could assemble a secondary and primary HDPE geomembrane liner system. A significant concrete structure, called a catch basin, was placed with the anchor wall that provides the foundation for a sophisticated series of piping manifold assemblies with pumps, valves, instruments, and leak detectors. Rigorous daily quality control inspections were performed to ensure the integrity of the new basin liners.

New electrical power and instrumentation equipment, raceway, and cables will interface with the new mechanical components. When thousands of feet of basin piping and underground waste transfer lines are installed and tested, a new unique floating cover system will be installed and commissioned to create an environmentally secure “pond” protected from the harsh weather extremes experienced at Hanford.

When complete, LERF Basin 41 will provide connectivity to operations control systems linking the three existing LERF basins. Basin 41 will provide a measure of safety, processing, and additional storage capacity required to support the significant volume of waste anticipated upon successful startup of the Hanford Waste Treatment Plant (WTP).