Consultant outlines two expansion options for Prairie View Landfill; investigation to begin

Marty Fallon, operations manager for Geologic Associates, told the Will County landfill committee that the county’s consultant team plans to pursue two parallel expansion concepts for the Prairie View Landfill: a vertical-only build within the existing waste footprint and a horizontal-and-vertical expansion to the northeast.

Fallon said the vertical-only concept would raise the final landfill form within the current footprint and would provide “approximately 24 and a half years of additional life.” The combined horizontal-and-vertical option would add roughly 10 additional years on top of that vertical gain but would require relocating the facility’s existing soil stockpile and vacating a roadway in the expansion area, Fallon said.

Why it matters: the county’s existing permitted landfill footprint is already partially built out and, at current filling rates, Fallon said the facility has about nine years of remaining capacity. The need to relocate a large soil stockpile and the site’s subsurface conditions will affect which expansion is feasible and how much additional lifetime the county can realize.

Fallon described the stockpile as containing “about 1,400,000 cubic yards of material” now and noted the existing facility design calls for about 1,600,000 cubic yards of surplus soil, meaning the pile could grow under current operations. He said the vertical-only option would not require moving that pile; the horizontal-and-vertical expansion would.

On engineering and environmental steps, Fallon said the team will extend the prior late-1990s subsurface investigation eastward, maintaining roughly the same grid spacing of borings. The investigation plan calls for adding nine borings to supplement the roughly 60 borings already on file, installing piezometers to evaluate groundwater elevations and aquifer behavior, and advancing borings at least 15 feet into bedrock at most locations (two locations will go about 40 feet to permit vertical gradient calculations). Fallon described laboratory testing that will follow (triaxial shear, permeability, moisture content) and said the modeling required by the state will include contaminant-transport and monitoring-network design.

Fallon said preliminary engineering checks on the landfill’s underdrain piping — described as polyethylene SDR‑11 pipe installed as part of the permanent design — indicate the pipes can handle the additional loading expected if the county chooses to increase height, but he emphasized those calculations are preliminary and engineering work will continue. He also said existing stormwater basins would likely be sufficient for the vertical-only option but that stormwater modeling would be required for any layout changes that shift basins.

On visual impact, Fallon showed line-of-sight renderings from Highway 53 and Arsenal Road and said tree cover and setbacks generally screen the landfill from adjacent roadways, though certain driveway gaps provide view corridors. Fallon noted one concept would raise portions of the final landform by as much as 170 feet relative to the current permitted profile; he recommended the county maximize “airspace” where engineering permits.

Schedule and next steps: Fallon said the team plans to stake borings and begin drilling “tentatively…Monday, the 21st, right after Easter,” with field work lasting about two to three weeks depending on rigs assigned and an additional week of aquifer testing. He said substantial office work would follow (boring logs, as-built diagrams, aquifer-test summaries, cross section extensions) and that it would likely be “a year to a year and a half or more” after the subsurface work before a full siting application would be ready. Fallon described a siting application as a large multi-volume package covering design, operating plans, construction quality assurance, closure plans, traffic analysis and real‑estate impacts.

Committee members asked for clarifications on life‑expectancy math and elevations. Fallon confirmed the additional years he cited are on top of the approximately nine years remaining under current operations. He also gave a permitted peak elevation for the existing landfill of 795 feet above sea level and said the 170‑foot increase would put the peak near 965 feet above sea level in the conceptual option shown.

Fallon said leachate is collected and sent to a publicly owned treatment works (POTW) for treatment. He also stressed that the site investigation will verify whether the geology in the proposed horizontal expansion area matches regional publications and the records from the existing facility; if not, design adjustments would follow.

The committee did not take a formal vote on an expansion during the meeting. Fallon said the investigation will proceed and the consultant will report results to the committee when laboratory and modeling work are complete.