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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, WESTON provided oversight of 19 Cone penetrometer (CPT) methane monitoring installations. Seventeen of the 19 CPT probe locations installed during this reporting period (CP44, 46, 49, 50, 51, 52, 53, 57, 61, RW22, 23, 24, 25, 26 GX8, 10 and 11) detected no methane during the initial open borehole monitoring with the Landtech GEM 500 methane detector. Gas probes CPT48 and GX9 both detected methane gas at 13.1% and 74.5 % respectively. At most locations, the utilities were cleared by the Hanover Park Public Works Department vacuum truck. The depth of up to 6 feet was vacuum extracted to check for presence of subsurface utility at each location. Prior to starting the CPT installation each vacuum location was filled with sand. Refer to Table 2 and Figure 2, for information on CPT Installations.
More subsurface investigation was conducted along the R.O.W. of Schick Road (north side) with the push of GX8, 9, 10 and 11 (on January 23rd and 24th). GX9 was the only probe that detected methane gas (at 74.5%). The R.O.W. of Schick has had a total of seven gas probes installed to date on the north and south side of Schick Road (GX 5, 6 and 7 were installed December 18, 2007 with no methane detection).
To date, (December 7, 2007 through January 25, 2008), approximately 97 methane gas probes (CPT probes shallow, intermediate and deep wells) have been installed in the investigation areas west and south of the Mallard Lake Landfill. Prior to the December 7th probe installation start-up, approximately 11 CPT probes had been installed by STS during the Wayne Township Groundwater investigation. Therefore, a total of 108 CPT gas probes have been installed to investigate the migration of methane gas from the Mallard Lake Landfill. Of the 108 total gas probes, currently 69 have no methane detection as January 25, 2008.
STS along with the CPT crew and WESTON will continue CPT probe installations and monitoring in the subdivisions east and west of County Farm Road as well as possibly more investigation along the R.O.W. of Schick Road due to methane detection at GX9 in the next week (Refer to Figure 2). Also, a historical review of methane gas probes revealed detections along the far east and northeast boundary of the landfill.
STS, WESTON and U.S. EPA personnel will review more records to determine if methane investigations should extend to this area.
These additional investigations and probe installations will provide more information to further assess the west, south and southwest extent of methane landfill gas migration. As of January 25th, the CPT installation investigation area is bounded by Green Bridge Lane to the west, Discovery Park to the east, Schick Road to the far south and Lawrence Avenue to the north.
Residential screening continued during this reporting period with a total of 63 homes screened and no explosive gases detected. Refer to Figure 1 and Table 1- Residential Screening Summary. Of the 63 homes screened for methane gas, 50 had explosive gas detectors installed. The detectors were installed after obtaining consent from the respective residents. The homes were located along Green Bridge Lane, Thistle Court, Morton Road, Whitney Drive, County Farm Road, Victor Lane, McCormick and DeForest Lane(on the east and west side of County Farm Road), DuPont, Eastman and Zeppelin Drive and Ridge Crossing. The majority of homes screened were conducted west of Morton Road as a result of the Public Meeting held January 17, 2008.
The explosive gas 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 % LEL. All residents are given written and verbal instructions on what to do when the alarm sounds. BFI has prepared a contingency plan with emergency contact information if an alarm sounds. In the contingency plan, residents are advised to call 911 which will notify the Hanover Park Fire Department.
To date, the U.S. EPA, STS (BFI contractors) and WESTON have screened 202 homes, installed 168 explosive gas detectors and visited a total of 273 homes (See Figure 1-Residential Screening Summary). BFI’s public relations consultants, Reputation Partners continue to schedule the residential screening and gas meter installations with field support by STS and WESTON personnel. Due to the detection of methane at CP probe GX9 south of Schick Road, residential investigation may be extended into subdivisions south of Schick Road.
On January 24th, probe TW-1 was purged and sampled for VOCs, total suspended solids, chemical oxygen demand and biological oxygen demand, ammonia, and chloride. Analytical results are currently pending.
No slam-bar sampling was conducted during this reporting period due to weather conditions, but STS has access to 30 properties to conduct the sampling.
U.S. EPA is meeting weekly on Monday’s at 2:00 PM to inform and update pertinent parties and agencies involved. The next meeting will be held February 4, 2008.
• STS to prepare for Shut-In Test on original CP probes with methane detection to determine radius of influence and potential hydraulic continuity of the methane gas; groundwater sampling and possibly soil gas sampling (summa canisters) is required prior to Shut-In test to ensure no release of any volatile organic compounds.
• BFI and STS 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;
• The western migration has been defined and the investigation will move to the South along Schick Road
• BFI and STS will propose soil gas sampling locations to the North and to the East
• BFI and STS will conduct soil gas sampling at designated shallow gas probe locations; and
• BFI and STS will install and sample shallow soil gas near residential homes (based on access); and
• BFI and STS will install and sample sub-slab sampling ports (based on access); and
• BFI and STS, will prepare a plan to improve and expand the methane recovery system and to address methane that has migrated off the property and;
• U.S.EPA and WESTON will continue to provide oversight of the work performed by BFI and STS.
• Clearing utilities along the right of ways in ample time for CPT installations
• Winter weather conditions interfering with completion of CPT push and probe installations, probe surface completions and groundwater sampling.
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