Publications
Discharge Permit-1845 Quarterly Status Report October 2018
Trichloroethene (TCE) and nitrate have been identified as constituents of concern in groundwater at the Sandia National Laboratories, New Mexico (SNL/NM) Technical Area (TA)-V Groundwater (TAVG) Area of Concern (AOC) based on detections above the U.S. Environmental Protection Agency (EPA) maximum contaminant level (MCL) in samples collected from monitoring wells. The EPA MCLs and the State of New Mexico drinking water standards for TCE and nitrate are 5 micrograms per liter and 10 milligrams per liter (as nitrogen), respectively. A phased Treatability Study/Interim Measure (TS/IM) of in-situ bioremediation (ISB) is being implemented to evaluate the effectiveness of ISB as a potential technology to treat the groundwater contamination at the TAVG AOC (New Mexico Environment Department [NMED] April 2016). The NMED Hazardous Waste Bureau (HWB) approved the Revised Treatability Study Work Plan (TSWP) (SNL/NM March 2016) in May 2016 (NMED May 2016). The SNL/NM Environmental Restoration Operations personnel are responsible for implementing the TS/IM of ISB at TAVG AOC in accordance with the Revised TSWP. Per the Revised TSWP, up to three injection wells (TAV-INJ1, TAV-INJ2, and TAV-INJ3) would be installed at TA-V in the vicinity of the highest contaminant concentrations detected in groundwater at monitoring wells LWDS-MW1, TAV-MW6, and TAV-MW10. The injection wells would be used to gravity-inject substrate solution and biodegradation bacteria to groundwater. The substrate solution consists of an inert tracer as well as essential food and nutrients for biostimulation. The substrate solution would be prepared in aboveground tanks. The TS/IM would be conducted in two phases: Phase I includes a pilot test followed by full-scale injection at the first injection well (TAV-INJ1); Phase II includes full-scale injections at the second and third injection wells (TAV-INJ2 and TAV-INJ3). The NMED Ground Water Quality Bureau (GWQB) requires a groundwater Discharge Permit (DP) for the operation of injection wells. NMED GWQB issued the DP-1845 to the U.S. Department of Energy/National Nuclear Security Administration (DOE/NNSA) for the SNL/NM TA-V Treatability Study injection wells on May 26, 2017 (NMED May 2017). The DP-1845 term started on May 30, 2017 and ends on May 30, 2022. Attachment A provides a copy of DP-1845. This quarterly report provides responses to DP-1845 Operating Conditions Terms and Conditions #3 through #8 and Monitoring and Reporting Terms and Conditions #10 through #17 for the April 1 to June 30, 2018 reporting period. The other Terms and Conditions are NMED statements of fact and do not require a response.