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EPA’s Emergency Response Branch was requested to assist the IEPA in March of 2007 at the Wayne Township Ground Water site in Northern DuPage County, Illinois. U.S. EPA upon reviewing available data and well logs from the Mallard Lake landfill discovered a boring conducted by BFI contractor Hearst and Assoc in April of 2006 with methane levels of 17.9% concentration within 50 feet of a residential neighborhood on the West perimeter of the landfill. U.S. EPA requested the operator of the landfill, BFI, and owner of the landfill, DuPage Forest District, to conduct an investigation outside the West boundary, South Boundary and on the Right-of Way to determine the extent of the gas migration off site. This landfill gas has historically contained high levels of Volatile Organic Compounds including vinyl chloride which was reported by the landfill operator to lead to ground water contamination exceeding the Maximum Concentration Limit (MCL) for vinyl chloride at the Western perimeter of the landfill.
During the first phase of the investigation conducted November 6-10, high levels of methane exceeding 75% in concentration were detected in temporary monitoring wells at locations within 30-50 feet from residential homes. The permeable zone containing this methane is 40-45 beneath the ground surface. BFI consultants STS, began installation of shallow monitoring wells on November 31, 2007.
During this reporting period, Cone penetrometer (CPT) investigations and installations were temporarily post-poned on December 19, 2007 due to the Holidays. The CPT crew returned on January 2, 2008 and CPT push probe installations resumed on January 3, 2008 at CP21 (right of way of Whitney Drive). This location had a total push depth of 44.67 feet with a probe screen set between 34.5 and 44.5 feet. However, due to potential calibration problems with the GEM 500 methane meter, the field crew was unable to obtain an accurate methane gas reading. STS is expected to receive a new methane meter January 4, 2007 and monitor CP21 again. Also mechanical problems with the CPT rig only allowed the CPT crew to push one location (CP21). The crew conducted necessary repairs to the rig and are expected to be fully functional on January 4, 2008. Also, approximately 19 new CPT locations have been proposed west of County Farm Road to further investigate the west southwest methane gas migration (See Figure 2).
Residential screening and explosive gas meter installations continued over the Holidays on December 22 and 26 2007 and January 2, 2008. A total of 26 homes were screened during this reporting period with no explosive gases detected (See Table and Figure 1). In addition, during this reporting period, 26 explosive gas detectors were installed in residences (upon obtaining approval of residents) along Jefferson Street, Whitney and Zeppelin Drive, Eastman, McCormick, DeForest and Wright Lane. These detectors are similar in size and operation to a smoke detector, and can detect the presence of methane, propane and other explosive gases. The detectors sound an audible alarm when the gases reach a concentration that is 25 % of the minimum necessary to cause an explosion. All residents are given written and verbal instructions on what to do if the alarm sounds. BFI has prepared a contingency plan with emergency contact information if an alarm or high level of methane is detected residents should call 911 and the Hanover Park Fire Department will resident.
To date, the U.S. EPA, STS (BFI contractors) and WESTON have screened 125 homes, installed 104 explosive gas detectors and visited a total of 200 homes(See Table and Figure 1). BFI’s public relations consultants, Reputation Partners scheduled the screenings and gas meter installations over the Holidays which were supported by STS and WESTON personnel.
On December 27, 2007, WESTON personnel conducted oversight of five residential slam-bar sampling locations ( 1910 DeForest Lane, 1860, 1865 and 1811 McCormick Lane and 1935 Lawrence Avenue) by STS (See Figure 3-1 thru 3-5). Up to four locations (front, back and both side yards) were monitored for methane gas (using a GEM 500 methane meter) to a shallow depth of three feet at each resident; no methane gas was detected at all sampling locations at each residence.
U.S. EPA is meeting weekly on Monday’s at 2:00 PM to inform and update all agencies involved. The next meeting will be held January 7, 2008.
U.S. EPA along with state and local representatives will hold a public meeting on Thursday, January 17, 2008 at Horizon Elementary School at 1701 Greenbrook Boulevard, Hanover Park, Illinois to discuss the Administrative Settlement with the Mallard Lake Landfill site (See Mallard Lake AOC Advertisement). The meeting will address the landfill gas investigation with local residents.
Investigative and remedial work plans submitted by BFI and STS have been reviewed by U.S. EPA and their consultants Weston Solutions, Inc. to investigate the gas migration and sample the landfill gas and ground water.
BFI public relations consultants Reputation Partners along with STS continue to distribute literature (door hangers) regarding residential screening and gas meter installation to local residents residing in the investigation area.
U.S. EPA entered into an Administrative Order of Consent (AOC) with BFI and the DuPage Forest District regarding methane gas investigation. The AOC requires BFI and the DuPage Forest District to complete the emergency assessment and investigation work to determine the extent of the methane gas leakage from the landfill, and to complete long-term measures to control the off-site migration of landfill gases.
• STS, WESTON and U.S. EPA will continue screening homes and installing explosive gas meters based on appointments scheduled by Reputation Partners public relations; and
• BFI and STS will continue methane gas migration investigation using the CPT rig and conducting weekly methane gas monitoring of existing and newly installed probes; and
• Conduct soil gas sampling at designated shallow gas probe locations; and
• Install and sample shallow soil gas near residential homes (based on access); and
• Install and sample sub-slab sampling ports (based on access); and
• BFI and their consultants, STS, will prepare a plan to improve and expand the methane recovery system and to address methane that has migrated off the property.
• Obtaining access to private homes to install shallow soil gas probes and sub-slab ports has been problematic; and
• Clearing of utilities along the right of ways in ample time for CPT installations.
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