ROCKY FLATS SOLAR EVAPORATION PONDS RCRA HYBRID-CLOSURE CASE STUDY

摘要

The Solar Evaporation Ponds (SEP)/Operable Unit 4 (OU 4), located at the Rocky Flats Plant (RFP) sixteen miles northwest of Denver, Colorado, is currently undergoing remediation/Resource Conservation and Recovery Act (RCRA) closure in accordance with the Rocky Flats Interagency Agreement (IAG) signed by the U.S. Department of Energy (DOE), U.S. Environmental Protection Agency (EPA) and Colorado Department of Health (CDH) on January 22, 1991. Based on the Phase I (source and soils) RCRA Facility Investigation/Remedial Investigation (RFI/RI) data and interpretations, the DOE and EG&G Rocky Flats, Inc. (EG&G) have selected a permanent surface engineered/isolation barrier as the technological option for remediation of the SEP. The DOE and EG&G will utilize all natural materials to create an impermeable barrier/structure to isolate the waste being left in place from impacting human health and the environment for a minimum of 1000 years. Our rationale for utilizing natural materials is two fold; 1) optimize long term performance of the barrier and; 2) design a structure which will be near maintenance free (passive remediation) for 1000 years. The DOE and EG&G have taken a proactive approach in providing post closure performance assessment for this RCRA closure action. An integrated monitoring system has been designed which will include monitoring the engineered barrier, vadose zone and ground water systems. Rocky Flats will integrate instrumentation into the permanent engineered barrier which will provide early warning of potential liquid migration through the barrier and into the waste zone.