Converter/Compressor Building, SWMU 089 2022 Performance Monitoring Report Kennedy Space Center, Florida

The Converter/Compressor Building (CCB) Performance Monitoring (PM) Report (PMR) presents the annual and biennial groundwater monitoring results. The reporting period covered under this PMR is from January 1, 2022, to December 31, 2022. This site has been designated Solid Waste Management Unit (SWMU) 089.

The 2022 reporting period represents the second year of post-air sparging (AS) PM at CCB. The AS Interim Measure (IM) previously operated at CCB from April 2014 until December 2020 to treat five Hot Spots (HSs). The objective of the AS IM was to reduce concentrations of volatile organic compounds (VOCs) in groundwater to levels that support transition to a long-term monitoring (LTM) phase.

In December 2022, annual and biennial groundwater monitoring was conducted (Post-AS PM, Year 2). A total of 48 wells were sampled, which included 25 wells scoped for annual sampling and 23 wells scoped for biennial sampling. Results indicated that MW0021, located in former HS 5, continues to be the only well with concentrations greater than natural attenuation default concentrations (NADCs). An IM Work Plan has been presented to the KSCRT to address NADC exceedances in the MW0021 area. Further documentation of the MW0021 area will be provided under separate cover.

For remaining wells in the monitoring network, the December 2022 dataset shows that concentrations of VOCs in annual and biennial wells remain less than NADCs with the majority of wells exhibiting stable or decreasing concentrations. Based on 2022 sampling results, the current size of the low concentration plume is 5.1 acres, reduced from 12.5 acres pre-IM, and the high concentration plume has been reduced from 5.8 acres to approximately 664 square feet around the MW0021 area.

The 2022 results continue to indicate that the corrective action objective for the AS IM has been met, which supports transition of the site from PM to LTM, except for the area around MW0021 where plans are in progress for an additional IM in this area. The current monitoring well network is recommended to be retained for the LTM program (25 wells annually and 23 wells biennially), but with the addition of two existing wells to the annual LTM schedule for vertical monitoring in areas where the highest VOC concentrations remain outside of the MW0021 area.

The next reporting period will be January 1, 2023, to December 31, 2023, and will include the annual monitoring event scheduled for December 2023. The next biennial sampling event will be conducted in December 2024. The contents of this PMR were presented at the June 2023 KSCRT Meeting, where Team consensus was reached on the recommendations and path forward for CCB (Meeting Minute 2306-M06, Decisions 2306-D05, D06).