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To address both soil and groundwater chlorinated solvent contamination identified in the area of a former dry cleaner (tenant spaces addressed as 2410-2412 10th Avenue) at the Sunrise Shopping Center facility, a Design Report Addendum/Remedial Action Plan (RAP) dated October 18, 2018, was submitted to WDNR proposing full-scale chemical injection activities. The RAP was approved by WDNR in a letter dated December 19, 2018. Subsequently, WDNR renewed the approval for coverage of the chemical injection of Potassium permanganate under WPDES permit WI-0046566-07 in a letter dated January 2, 2019.
Prior to beginning remedial activities, 35 chemical injection points was installed in January 2019, including the placement of 27 shallow (3.5-ft deep) and four (4) deeper (9-ft deep) injection points for use in the gravity feed infiltration gallery. The other four (4) injection points were installed to 12.5-ft below grade and replicated injection locations initially completed during July 2018 pilot-scale chemical injection activities. After completing construction of the infiltration âsystem,â a small volume test injection was performed on February 4, 2019, to evaluate for leakage, verify suitable infiltration, etc. Full-scale injections via gravity feed were conducted on May 14-17, May 29, June 25-26, and June 29, 2019. Chemical injection volumes were provided on the monthly DMRs submitted to WDNR as required under WPDES permit WI-0046566-07. Additional injection will be performed at least once per month until the intended amount of Potassium permanganate is distributed across the 35 injection locations.
In addition to the remediation of the chlorinated contamination in the soil and groundwater, the sump water treatment system installation within the Ace Hardware building was completed in January 2019 (a seal have previously been installed over the sump in September 2018). Prior to beginning discharge of treatment water from the system, a request for coverage under WPDES permit WI-0046566-07 was submitted under cover letter dated February 20, 2019. WDNR granted coverage of the additional discharge from the treatment system in a letter dated April 10, 2019. The treatment system began operation on May 14, 2019. Weekly samples were collected of the discharge for the first four (4) weeks on May 15, 23, 29, and June 6, 2019. The first monthly discharge sample was collected on June 25, 2019. Electronic reporting of the discharge sample results is completed monthly, as required under WPDES permit WI-0046566-07.
Two (2) quarterly groundwater sampling events were also conducted during the first semi-annual 2019 reporting period in order to assess the groundwater concentration of Tetrachloroethene (Perc) in MW-5. The first quarter sampling was performed on January 25, 2019, with results provided in the Quarterly Groundwater Sampling Report dated February 13, 2019. The second quarter groundwater sampling was performed on April 29, 2019, and the results were provided in the Quarterly Groundwater Sampling Report dated May 16, 2019. The quarterly sampling indicates that Perc concentrations in the area of MW-5 remain above the Enforcement Standard, but additional injection has not yet been performed in the vicinity of MW-5 (all injection activities were performed within the tenant spaces to reduce source area soil concentrations). Quarterly sampling of MW-5 will be continued to monitor remedial progress from ongoing injection activities.
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