Environmental fieldwork planned at the Old Southington Landfill
Landfill Gas Barrier Trench Installation and Notice of Five-Year Review As part of its Second Five-Year Review of the cleanup remedy at the Old Southington Landfill (OSL). the United States Environmental Protection Agency (EPA) and the Connecticut Department of Environmental Protection (DEP) requested that the Performing Parties evaluate the effectiveness of the cleanup up work completed at the landfill. This included evaluating the existing landfill gas collection system. inspecting the landfill cap for rips and tears. conducting fish sampling in Black Pond, and continued groundwater monitoring. The Five Year Review will be completed during 2010. As part of this overall evaluation, the Performing Parties recently conducted a helium gas study in the northern end of the landfill. This part of the landfill was chosen for the test because of its close proximity to the residential area. The study consisted of injecting helium, a safe inert gas, into the capped landfill and measuring for it on the outside area of the cap. This study revealed that a very small amount of helium migrated from the landfill. Thus, as an added measure of precaution, the Performing Parties have proposed to augment the existing landfill gas collection system with the installation of a gas barrier trench aJong the north perimeter oftbe-laRdfil! cap SQuthef Rejcan Road. The barrier trench Which includes a liner installed beneath the surface will extend from Old Turnpike Road to Black Pond generally along the vicinity of the existing fence line. The installation of the gas barrier liner will involve the use of excavators and other earth moving equipment. The work will start on December 14, 2009 and will take approximately 2 to 3 weeks to complete. Work will not be performed during the Christmas Holidays. Work hours will take place approximately between 7:00 AM - 5:00 PM. Since weather conditions are currently favorable for construction (Le. ground is not frozen and the water table is low) the Performing Parties will to do the work now rather than wait for spring/summer season. Air monitoring will be conducted during open excavation activities. A silt fence will be installed down slope of the proposed gas barrier trench to control erosion. Some of the trees on the landfill side of Rejean Road will be moved or replaced with new ones. The chain link fence will be moved out a few feet toward Rejean Road to allow for the installation of the gas barrier trench. A fire hydrant may be relocated to a nearby location. The trench will be 560 feet long. two feet wide, and will vary in depth from 3 to 8 feet depending on the depth to the water table. The barrier trench will be placed one foot below the water table. The trench will be excavated using a track-mounted excavator. Only up to 100 foot long sections of the trench will be open at any time to allow the crew time to complete the work in these sections and backfill by the end of the day. (Over)
The excavated soil will be temporarily staged in a general area. Because this soil is not from under the cap it is not contaminated. If small sections need to remain open until the next day, the crew will cover these areas with panels as a safety measure. They will also cover any excavated material that has not been backfilled. An impermeable liner will be placed inside the trench and backfilled. Following completion of construction, the disturbed area will be graded and covered with straw. The silt fence will remain in place through the winter and the disturbed area will be seeded in late spring 2010. Any additional restoration of disturbed areas (fencing, trees, plants) will also be completed in the spring. Upon completion, this work will not affect the current passive recreational use of the northem part of the landfill. The work on the landfill will be performed on behalf of the Performing Parties by Loureiro Engineering Associates, Inc. of Plainville, Connecticut under supervision of the EPA and DEP. To continue to keep the community informed of the status of the Old Southington Landfill, EPA will hold a public meeting in spring 2010 to update local residents and businesses about the status of activities conducted this fall and to discuss any future environmental work. The presentation will include the Five-Year Review, the landfill gas barrier trench installation, the results of fish tissue sampling of Black Pond performed in October 2009, the results of on-going groundwater monitoring, and the plan for any future work. A meeting notice will be circulated as the date is selected and the agenda is better defined.
Ifyou have questions concerning the gas collection system evaluation study and the barrier trench installation, please contact Almerinda Silva, EPA Remedial Project Manager, at617-918-1246 orbye-mail firstname.lastname@example.org, orJim Murphy, EPA Community Outreach Coordinator, at 617-918-1028 or bye-mail at email@example.com. If you have any health related questions, please contact Sharee Rusnak, CT Department of Public Health at (860)509-7583 or by email at sharee. firstname.lastname@example.org.