Groundwater – Completed Activities

June 2018

  • Continued operations of the Temporary Groundwater Treatment System (TGTS) at approximately 20 gpm. Work completed in June includes:
    • Completed TGTS sampling in accordance with the”100% Design Report for Temporary Treatment System.”
    • Completed monthly hydraulic monitoring on June 22, 2018.
    • Completed quarterly groundwater sampling campaign from June 25-29.
    • Continued carbon unit sampling for TCE and iron to monitor for breakthrough.
    • Completed EW-1 re-development from June 18-20. All re-development water was collected and treated through the treatment system.
  • Continued coordination with groundwater treatment system vendor on design and PLC system.
  • Completed Demonstration of Compliance Report for June 2018.
  • Selected Senate Construction as the building contractor and completed contract negotiations and received preliminary building drawings.
  • Met with Board of Health, Building Commissioner, Zoning Department, and Conservation Commission on June 27 to discuss building plans.

May 2018

  • Continued operations of theTemporary Groundwater Treatment System (TGTS) at 20 gpm. Work completed during May includes:
    • Completed TGTS sampling in accordance with the “100% Design Report for Temporary Treatment System.”
    • Completed monthly hydraulic monitoring on May 11, 2018.
    • Completed monthly sampling of MW-SD44, MW-SD42A, Assabet 1A and 2A.
    • Monitored influent, midfluent, and effluent of Carbon canisters for evidence of breakthrough.
    • Performed RGP Sampling on May 30, 2018.
    • Completed carbon change out in GAC units on May 31, 2018.
  • Continued work with groundwater treatment system vendor on design and procurement process.
  • Completed Demonstration of Compliance Report for May 2018.
  • Issued Request for Proposals for the Building Construction to three potential contractors on May 25, 2018.

April 2018

  • Continued operations of theTemporary Groundwater Treatment System (TGTS) at 20 gpm. Work completed during April includes:
    • Completed TGTS sampling in accordance with the “100% Design Report for Temporary Treatment System.”
    • Completed monthly hydraulic monitoring on April 25, 2018.
    • Completed monthly sampling of MW-SD44, MW-SD42A, Assabet 1A and 2A.
    • Monitored influent, midfluent, and effluent of Carbon canisters for evidence of breakthrough.
  • Continued work with groundwater treatment system vendor on design and procurement process.
  • Completed Demonstration of Compliance Report for April 2018.
  • Submitted the “95% Design Report” and “Response to Comments on 90% Design Report” to the agencies on April 17, 2018.

March 2018

  • Continued operations of theTemporary Groundwater Treatment System (TGTS) at 20 gpm. Work completed during March includes:
    • Completed TGTS sampling in accordance with the “100% Design Report for Temporary Treatment System.”
    • Completed monthly hydraulic monitoring on March 26, 2018.
    • Completed quarterly groundwater quality sampling in accordance with the 100% Design Report, Temporary Groundwater Treatment System; results are not yet available.
    • Completed monthly sampling of MW-SD44, MW-SD42A, Assabet 1A and 2A.
    • Monitored influent, midfluent, and effluent of Carbon canisters for evidence of breakthrough.
  • Continued work with groundwater treatment system vendor on design and procurement process.
  • Met the representatives of the WR Grace Acton Site on March 22 to discuss the iterative groundwater model calibration results. A revised groundwater modeling report is being prepared to document the agreed “Grace/NMI Joint Regional Groundwater Model.”
  • Submitted Response to Comments and Revised RDWP on March 9.

February 2018

  • Continued operations of the Temporary Groundwater Treatment System (TGTS) at 20 gpm. Work completed during March includes:
    • Completed TGTS sampling in accordance with the “100% Design Report for Temporary Treatment System.”
    • Completed monthly hydraulic monitoring on February 5, 2018.
    • Completed monthly sampling of MW-SD44, MW-SD42A, Assabet 1A and 2A, results are provided in Attachment 1.
    • The system was shut down on February 23 for Carbon Replacement and was restarted on February 24.
    • Monitored influent, midfluent, and effluent of Carbon canisters for evidence of breakthrough.
    • Performed RGP Sampling on February 26, 2018.
  • Continued work with groundwater treatment system vendor on design and procurement process.
  • Performed a small pump test to identify specific capacity of MW-SD34 and collected groundwater quality samples. Information gathered will be used to analyze possible benefits of EW-2.
  • Began drafting 95% Design Report.
  • Continued preparing Response to Comments and Revisions to the RDWP.

January 2018

  • Continued operations of the Temporary Groundwater Treatment System (TGTS) at 20 GPM. Work completed during January includes:
    • Completed TGTS sampling in accordance with the “100% Design Report for Temporary Treatment System”.
    • Completed monthly hydraulic monitoring on January 10, 2018.
    • Completed monthly sampling of Assabet 1A and 2A.
    • Completed monthly sampling of MW-SD44 and MW-SD42A.
  • Continued work with groundwater treatment system vendor on design and procurement process.
  • Submitted the 90% Removal Design to the Agencies on January 12, 2018.

December 2017

  • Continued operations of the Temporary Groundwater Treatment System (TGTS) at 20 GPM. Work completed during December includes:
    • Completed TGTS sampling in accordance with the “100% Design Report for Temporary Treatment System”.
    • Completed monthly hydraulic monitoring on December 18, 2017.
    • Completed quarterly Groundwater Quality Monitoring.
    • Changed out the Carbon in the GAC Filters on December 12.
    • Re-developed EW-1 on December 19 to increase capacity. Water generated during redevelopment was collected and treated through the TGTS before being discharged.

November 2017

  • Continued operations of the Temporary Groundwater Treatment System (TGTS) at 20 GPM. Work completed during October includes:
    • Completed TGTS sampling in accordance with the “100% Design Report for Temporary Treatment System”.
    • Completed monthly hydraulic monitoring on November 29, 2017.
    • Completed monthly groundwater sampling of MW-SD42A, MW-SD44, Assabet1A, Assabet2A.
  • Installed and surveyed a staff gauge and piezometer in both Muskrat and Turtle Ponds. Data from these will be used to assist in calibrating the NMI GW Model.

October 2017

  • On October 26, de maximis participated in an on-site meeting with the Community Groups and the Agencies to provide an update on the status of the temporary groundwater treatment system, results of the Treatability Study, and the next steps in the design/construction of the final system.
  • Continued operations of the Temporary Groundwater Treatment System (TGTS) at 20 GPM. Work completed during October includes:
    • Completed TGTS sampling in accordance with the “100% Design Report for Temporary Treatment System”.
    • Completed monthly hydraulic monitoring on October 4, 2017.
    • Completed monthly groundwater sampling of MW-SD42A, MW-SD44, Assabet1A, Assabet2A. Samples were collected from MW-BS15 to assist in modeling of the 1,4-dioxane plume.
  • Completed Pilot Test of the iron pre-treatment to reduce iron concentrations in influent of Vanox Unit.

September 2017

  • Continued operation of the Temporary Groundwater Treatment (TGTS) at 20 GPM. Work completed during August includes:
    • Completed TGTS sampling in accordance with the “100% Design Report for Temporary Treatment System”.
  • Completed Pilot Tests of the Evoqua System.
    • Submitted the “Pilot Test Summary” memorandum to the Agencies on 8SEP2017 summarizing findings during system operations.
  • During the week of September 11, 2017, de maximis completed the third monthly groundwater sampling campaign.

August 2017

  • Continued operation of the Temporary Groundwater Treatment (TGTS) at 20 GPM. Work completed during August includes:
    • Continued operations of the Evoqua Pilot System.
    • Completed TGTS sampling in accordance with the “100% Design Report for Temporary Treatment System.”
  • On August 14 and 15, de maximis completed the second monthly groundwater sampling campaign in accordance with the “100% Design Report for the Temporary Treatment System.”

July 2017

  • Continued operation of the Temporary Groundwater Treatment System (TGTS) at 20 GPM. Work completed during June includes:
    • Began testing the Evoqua Pilot System- an advanced oxidation process (AOP) identified as a reliable solution for destruction of 1,4-dioxane.
    • Replaced Granular Activitated Carbon
  • During the week of July 10, 2017, de maximis performed a round of hydraulic monitoring and groundwater sampling event in accordance with the approved Temporary Treatment System 100% Design Report and the de maximis

May 2017

  • Executed a Long-Term Lease Agreement with Acton Water District (AWD) on May 15, 2017 for access to the property at 16 Knox Trail.
  • Completed installation of the Temporary Groundwater Treatment System on the property at 16 Knox Trail. Work completed during May includes:
    • Installation of the discharge line that crosses the underground Eversource Line.
    • Programming of the PLC to monitor and maintain flows.
    • Connection to electrical service.
    • Completed pre-start up procedures (system hydration, bump test, etc.)
  • Installed Transducers in 13 locations to gather hydraulic monitoring data pre/post system startup.
  • Performed initial Water Quality Monitoring sampling campaign during the week of May 1: 31 wells and 3 surface water locations were sampled.
  • Started the treatment system up on May 23 and began treatment system monitoring in accordance with the “100% Design Report for Temporary Treatment System” (Sampling on Day 1, Day 3, Day 7, etc.)

April 2017

  • Submitted the revised version and Response to Comments for the PDI Evaluation Report for Aquifer Pump Test on April 3, 2017.
  • Submitted the revised version and Response to Comments for the Treatability Study Work Plan on April 5, 2017.
  • Began installation for the Temporary Groundwater Treatment System on the property at 16 Knox Trail. Work completed includes:
    • Installation of the treatment shed
    • Installation of manholes for EW-1 and the discharge line to the outfall location.
    • Installation of the outfall system
    • Installation of extraction pump

March 2017

  • Participated in an online webinar with the Agencies and Geosyntec on March 24, 2017 to discuss the status and findings of the GW Mod-Flow Model as recalibrated with new MW-46 data.
  • Submitted the revised 100% Design Report for the Temporary Groundwater Treatment System (TGTS) on March 15, 2017.
  • Redesigned the discharge outfall to address comments received from MA NHESP. The re-worked design removed the presence of gabion baskets and replaced them with rip-rap to limit the effects the outfall may have on benthic species habitat.

February 2017

  • Potential treatment vendors returned their proposals for treatment systems and alternatives. Initial review of proposals and technology selection began
  • Continued construction of the Temporary Groundwater Treatment System (TGTS). The TGTS system will contain carbon canisters to filter and treat extracted groundwater, before being discharged at an outfall location adjacent to the Assabet River.

January 2017

  • Participated in a meeting at the site on January 19 to present findings from the MOD-FLOW Groundwater model and provide a status update to the towns of Acton and Concord.
  • The “100% Temporary Design- Temporary System”, was submitted to the EPA on January 26. This design report provides an outline of steps to be taken to temporarily contain the 1,4-dioxane plume until a permanent pump and treat system is designed.
  • Respondents began coordination with the Town of Acton on a long-term lease for a portion of the property at 16 Knox Trail, which the groundwater treatment system will be housed on.
  • An additional cluster of monitoring wells was installed approximately 100 feet east of Assabet 1A. This cluster will assist in delineating the extent of the 1,4-dioxane plume and provided greater details of the conditions in close proximity to Assabet 1A.
  • Construction of the Temporary Groundwater Treatment System began.

December 2016

  • Completed shipments of all water collected during the pump-test to US Ecology for treatment and disposal.
  • Continued development and write-up of the 100% Temporary Design for the temporary groundwater treatment system. Coordination with the Town of Acton continued to select possible discharge outlets.

November 2016

  • During November, EW-1 was redeveloped, resulting in increased specific capacity. The results indicate that EW-1 is capable of generating 20 gpm, the rate of flow targeted to perform hydraulic containment at that location.
  • Began work to develop a Groundwater Model for the site. This model will be used to assist in identifying optimal pumping locations and capabilities and assist in designing treatment options.

October 2016

  • Participated in an on-site meeting on October 26, with the EPA, MADEP, and subcontractors to discuss Remediation General Permit discharge requirements, treatment options, and status of groundwater work. Discussions were focused on potential treatment options and treatment requirements for discharge to the river.

September 2016

  • Completed installation of the extraction well (EW-1) and MW-SD45 during the week of September 12, on the Acton Water District property, located at 16 Knox Trail, Acton MA.
  • Completed pump and step tests of EW-1 to identify the specific capacity of EW-1 and identify potential pumping rates for hydraulic containment.

August 2016

  • Continued installation of monitoring wells and collected first round of analytical samples and hydraulic elevation data.

July 2016

  • The Adminstrative Order on Consent for the Non-Time-Critical Removal Action (NTCRA) for Groundwater became effective on July 11 and the Groundwater NTCRA Trust Agreement was submitted to and approved by the EPA.
  • Respondents named de maximis, inc. as General Contractor and Project Coordinator of the NTCRA.
  • Began installation of monitoring wells, in accordance with the Pre-Design Investigation Work Plan.

 

Last updated on July 31, 2018