Hartford Landfill

Problem

The Hartford Landfill, approximately 96 acres in size, began operation in the 1940s, and for many years was considered an eyesore. In 2007, the process of capping and closing the landfill began. By 2011, only 35 acres remained uncapped.

The local authorities wanted to follow a popular trend of adding a photovoltaic (PV) solar array on top of the remaining uncapped landfill. The problem? Doing so required a very reliable capping solution that wouldn’t require frequent maintenance. They needed a technology that wouldn’t fail and compromise the supported solar array.

They considered three capping technologies. The first option was to cap the site with a traditional vegetative cover. The second option was to cap the landfill with an exposed thermoplastic polyolefin (TPO) membrane, which is commonly used in the roofing industry. The third option was an EST System called ClosureTurf®.

In 2013, after an in-depth evaluation of proposals received, they approved the installation of the EST System technology as the final membrane cap for the solar electric generating facility at the Hartford Landfill, making it a one-of-a-kind in the industry to date to incorporate this capping system technology and the deployment of a PV Solar array on a landfill.

Solution

The 35-acre final closure phase of the Hartford Landfill began by using the innovative capping technology, ClosureTurf®.

ClosureTurf® is classified as an EST (Engineered Synthetic Turf) system and is approved for use as a final closure system in the waste containment industry. The innovative technology uses a “geosynthetic erosion layer” as part of a final cover system in lieu of a vegetative cover when compared to the traditional method.

There are three main components of an EST system: a high-friction structured geomembrane overlain by an engineered synthetic turf, which is in filled with sand or a binded in fill depending upon the magnitude and type of erosive forces present in site specific locations.

EST systems like ClosureTurf® is becoming more widely accepted for use as an alternative cover since it meets or exceeds regulatory requirements mandated by the EPA, and can be less costly to construct and maintain for site owners over time. Additional advantages include superior erosion and wind resistance, long-term geomembrane integrity, ease of accessibility, it is quick and easy to install, and offers several economical benefits throughout its life cycle.

It’s superior reliability was the reason why it was chosen as the foundation for the 5-acre solar field on the landfill, a first-of-its-kind usage.

Outcome

The closure at the Hartford Landfill was completed in 2013, with the PV solar field onlined on June 2014 (four months ahead of schedule).

Atop of the 35 acres of ClosureTurf® rests the 5-acre solar field that is surrounded by soil and vegetation to minimize dust build-up that could reduce solar efficiency. The solar field generates about one megawatt of renewable energy, enough to power about 1,000 homes when operating at full capacity.

The use of ClosureTurf® allowed the engineering teams to leave previously installed landfill environmental protection systems intact, including its gas-collection system. This yielded significant project cost reductions.

Additionally, the use of ClosureTurf®, instead of traditional closure systems, across the 35-acre project saved about $1.4 million.