A large, municipal solid waste landfill contracted with American Environmental Group (AEG) to install an anchored, exposed geomembrane cover and landfill gas (LFG) collection system.  The site was in an area of heightened scrutiny and the project was time-sensitive. AEG established a 7-day work week program in order to fulfill the project ahead of schedule. Meeting all of the project’s fast-tracked goals, and finishing the work within budget, was made possible largely by two elements of the project:

• AEG’s ability to provide all of the essential services: the supply and installation of geosynthetics, the design and construction of the LFG system, and the core operations and maintenance (O&M) services.
• The first utilization of a soil anchor ballast geomembrane cover design in the United States.

The turnkey services provided by AEG maximized communication, coordination and team knowledge. The unique cover design allowed for faster installation and lower job costs.

Geosynthetics

The on-site work of AEG’s Geosynthetics Division involved the installation of roughly 2,000,000 SF of 40-mil textured high-density polyethylene (HDPE) geomembrane. Because it was to be an exposed geomembrane, the material was tinted green by the manufacturer to better blend the special cover into the surrounding landscape.

Additionally, more than 2,000,000 SF of nonwoven geotextiles were installed for protection, drainage and filtration control, and interface friction performance such as on slopes.

Of note, the trenchless anchored ballast approach was new not only to this site but to the United States. It has proven to be the right choice. The installation schedule was decreased dramatically, and the job cost was lowered too. The use of soil anchor ballast allowed the construction crew to eliminate traditional ballast trenches.

Ultimately, this decision between AEG and the site owner enabled the quick response needed for long-term odor control. The site continues to function properly.

Landfill Gas Collection

AEG’s Landfill Gas Construction division’s experience was vital to the success of the project. The Geosynthetics Division’s work could not be completed without the LFG Division’s work occurring first. But the narrow construction window for covering the site, given the previously assessed odor violations, meant that the geosynthetics work needed to follow the LFG work closely. Open trenches were not even permissible overnight, due to the odor concerns and penalties.

Precision and expertise were essential. The LFG Division performed gas well drilling and installed high-density polyethylene (HDPE) piping safely but quickly.

Day by day, as the LFG system was installed, the liner installation followed almost immediately. The successful coordination of this interdependent construction was, again, chiefly due to AEG’s ability to provide all of the diverse skills and materials required.

Operations & Maintenance

The O & M Division worked with the owners and site crew throughout the project to ensure that the project unfolded as planned and that the critical LFG system would function properly to control odor and responsibly manage the landfill gas, such as through flaring.

Key services included LFG well tuning and gas monitoring.

AEG continues to provide O & M services to this site.

After several years of regulatory action and more than 350 documented citizen complaints, a mixed-use waste facility that had been in operation for just eight years was closed. In an unprecedented move, the Ohio EPA utilized the site’s financial assurance and a design-build contract to speed forth on closure, the exemplary success of which may provide a template for future emergency closure response.  American Environmental Group—an Approved Installation Contractor (AIC), as recognized by the International Association of Geosynthetic Installers (IAGI)—was proud to be part of this first-of-its-kind collaboration between regulators, designers and contractors.

The relatively young age of the landfill meant that waste was still quite active in its decomposition. This presented both settlement and heating concerns. AEG provided a solution that was safe and met stability requirements of the odor-controlling cover system against slope failure.

The General Contractor (R.B. Jergens) excavated benches into the subgrade. Waste that was encountered, some of which suggested asbestos content, was relocated during subgrade preparation.  Geocomposite material was then installed by AEG as a gas collection layer beneath the membrane and as a synthetic drainage layer above the geomembrane. To cap the site, 40-mil, textured linear low-density polyethylene (LLDPE) geomembrane was placed.

AEG’s expert team installed more than 4,500,000 SF of geosynthetic materials in less than 8 weeks.

The sum total of all closure activities (including the design phase) took just 4.5 months—a remarkable turnaround for a 46-acre site.

Special thanks to Kevin L. Harshberger, P.E., R.B. Jergens Contractors – Project General Contractor, for providing background details on the site (and for his project management).

American Environmental Group installed the United States’ FIRST solar energy-generating exposed geomembrane cap (EGC) on Republic Services, Inc.’s Tessman Road landfill near San Antonio, Texas in early 2009. The success of that project has led to AEG working on the second EGC landfill project (Atlanta, Georgia).

The Texas project’s design uitilzes a TPO geomembrane, which is a flexible material installed similarly to polypropylene geomembranes. The modified TPO, however, is designed for longer-term exposure and service life, which this solar energy project requires. AEG’s work on the 5.6-acre EGC system involved installation not just of the TPO membrane but of the entire solar-energy array, which included bonding 35 flexible “solar pods” to the geomembrane panels. Each pod consisted of 2 rows of 15 thin-film photovoltaic panels (1,050 panels in total). As a first-of-its-kind installation, AEG needed to establish a unique staging area to perform the initial bonding of the solar films to the TPO panels. A special adhesive from Sika was used, which required precise temperature management and placement to ensure each solar panel’s optimal performance and durability.

After the photovoltaic panels were properly adhered to the TPO, the composite panels were placed in cover position and welded to adjoining panels. The scrim-reinforced TPO used at Tessman is similar to reinforced polypropylene, but pre-fabricated was not allowed for this project. Pre-fabrication allows large sections of geomembrane to be seamed in the controlled environment of a factory or warehouse, rather than on site with the variances of weather, wind and site layout and topography.

But given the thickness of the material (60 mil), the uniqueness of the project, and the need to begin the installation immediately, pre-fabrication was not explored. Instead, AEG’s certified technicians performed the work. American Environmental Group, Ltd. is an Approved Installation Contractor, a designation awarded by the International Association of Geosynthetic Installers (IAGI). For Tessman, AEG used only technicians who hold IAGI Certified Welding Technician (CWT) status.

More than 35,000 LF of seaming was performed without issue. No seams failed their quality control tests. The combined power output of the site’s cover and affiliated landfill gas collection and conversion system is XXXX MW, which is equivalent to the annual power consumption of YYYYY homes.

Additionally, American Environmental provided and continues to provide Landfill Gas (LFG) System and Operations & Maintenance services to the Tessman Road site.