[en] This remedial investigation/feasibility study (RI/FS) evaluates alternatives for placement of remediation waste generated during remediation of CERCLA past-practice sites on the Hanford Reservation. With the exception of the no action alternative, all of the alternatives evaluated in this RI/FS include a CERCLA landfill referred to as the Environmental Restoration Disposal Facility (ERDF). The ERDF would serve as the receiving facility for most of the waste excavated during remediation of CERCLA past-practice sites. The primary element of the ERDF is a single trench excavated below existing grade that will be filled with remediation waste and closed with a protective surface barrier. Supporting facilities, which may include administrative buildings, railroad spurs, waste off-loading and transport equipment, and decontamination facilities, will also be included as part of the ERDF. Only remediation waste that originates within the Hanford Site will be placed in the ERDF. The waste is expected to consist of dangerous/hazardous wastes, polychlorinated biphenyl (PCB) and asbetos waste, low-level radioactive waste, and low-level mixed waste (containing both dangerous and radioactive waste)