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Home My WebLink AboutFINAL - June 2019 Quarterly Gas Monitoring Report - Nantucket Landfill 75 State Street, Suite 701 Boston, Massachusetts 02109 tel: 617 452-6000 August 14, 2019 Mr. Mark Dakers Massachusetts Department of Environmental Protection Southeast Regional Office 20 Riverside Drive Lakeville, Massachusetts 02347 Subject: Summary of Landfill Gas Sampling - June 2019 Nantucket Landfill Nantucket, Massachusetts Dear Mr. Dakers: On June 19, 2019, CDM Smith Inc. (CDM Smith) personnel field analyzed landfill gas samples at the Nantucket Landfill in Nantucket, Massachusetts. The sampling was performed in accordance with the Massachusetts Solid Waste Management Regulations (310 CMR 19.132) and the approved Environmental Monitoring Plan, prepared by SECOR International Inc., in July 1999 for the landfill. A site plan of the landfill has been included in Appendix A. Post-closure landfill gas monitoring consisted of sampling 13 landfill gas wells, including LGW-1 through LGW-13 and two landfill gas probes, Probes #1, #2 as shown on the attached site plan. Each well and location was sampled for methane (CH4) in percent volume and lower explosive limit (LEL), carbon dioxide (CO2), oxygen (O2), using a Landtec GEM 2000 Gas Analyzer; volatile organics using an organic vapor meter (OVM), lamp eV 10.6; and hydrogen sulfide (H2S) using an Interscan1000 Meter. A table of the initial and final gas readings has been included in Appendix B. The following summarizes the results of the gas sampling:  Methane was detected above the regulatory limit of 25% of the LEL in well location LGW-9 during this round. The final concentration in LGW-9 was 9.9% by volume, equivalent to 198% of the LEL. Probe #1 and Probe #2 were installed this round to detect gas migration around LGW-9; methane was non-detected in Probe #1 and Probe #2 was non-detect for methane. Probe #1 and Probe #2 results indicate that methane is not migrating beyond the property boundary. Exceedances at this monitoring location were sent to MassDEP within the 24-hour notification time frame. A copy of the email sent to MassDEP has been included in Appendix C.  Methane was only detected in LGW-9, methane was not detected at any of the other monitoring locations.  Carbon dioxide was detected in all monitoring locations with final concentrations ranging from 0.2% to 12.1%. Mr. Mark Dakers August 14, 2019 Page 2  Oxygen was detected in all monitoring locations at final concentrations between 6.0% and 20.9%.  Hydrogen sulfide was not detected at any monitoring locations.  VOCs were not detected at any of the monitoring locations. Prior to the October 2013 sampling round, landfill gas had been consistently detected in monitoring well LGW-9, located on the south side of the site near the compost pad. Subsequently, an adjacent compost pile to LGW-9 was removed which resulted in no landfill gas detected at LGW-9 in sampling rounds conducted during October and December 2013. Since 2013, the compost pile has fluctuated in size; the gas results have been consistent with the fluctuations of the compost pile’s size. The next sampling round will be completed in September 2019. Please do not hesitate to call me at (617) 452-6635 if you have any questions or require additional information. Very truly yours, Mary Mancini, P.E., BCEE Senior Project Manager CDM Smith Inc. Attachments cc: Robert D. McNeil, Nantucket Public Works Director Whitney Hall, Waste Options File: 1910/78240/03/05/01/2018/June 2019 1 Journeay, Patrick M. From:Journeay, Patrick M. Sent:Thursday, June 20, 2019 3:11 PM To:Mark.Dakers@state.ma.us Cc:Rob McNeil:; Santoro Jr, Frederic; colleen.ferguson@state.ma.us Subject:24-Hour Gas Exceedance Notification - June 2019 Nantucket Landfill, Nantucket Attachments:Nantucket Landfill Exceedance Map - June 2019.pdf Good Morning Mark, In accordance with 310 CMR 19.132 (5) (h), CDM Smith on behalf of the Town of Nantucket hereby notify MassDEP that during landfill gas sampling on June 19, 2019, the concentration of methane gas exceeded 25% of the Lower Explosive Limit (LEL) at one landfill gas well located to the east of the landfill site. The percent of the LEL by volume detected at these locations are as follows: LGW-9 198 % LEL Probe #1 0 % LEL Probe #2 0 % LEL Landfill gas well LGW-9 is located adjacent to Massasoit Bridge Road which is an unpaved narrow path in the southeast corner of the site. LGW-9 had a methane gas exceedance of 198% LEL. Probe #1 was conducted closer to the road and fence line approximately 6-8 feet in a southern direction from LGW-9; no gas was detected in Probe #1. An additional probe, Probe #2, was conducted approximately 10-15 feet south from Probe #1; no gas was detected in Probe #2. The results of this sampling round are consistent with previous sampling rounds. The well is located near a composting pile and is approximately several hundred feet away from the active landfill, we do not believe the methane detected in this well is from the landfill cell. There are no houses or utilities in this area; it is open land with dense vegetation. Attached is a site plan showing the landfill gas monitoring locations. A report summarizing all the sampling results will be submitted in the next few weeks. Please feel free to call or email Mary Mancini at (617) 452-6635 or mancinimc@cdmsmith.com if you have any questions or require any additional information. Thank you, Patrick Patrick Journeay Environmental Engineer CDM Smith 75 State Street, Boston, MA 02109 617.452.6632 cdmsmith.com