Leachate Collection System

OENJ Cherokee Corporation
Bayonne, New Jersey

Project Description:

Edgeboro International, Inc. was retained to construct a leachate collection system utilizing a bio-polymer trenching methodology and a pneumatic pumping system for OENJ Cherokee at the Bayonne Redevelopment Site, in Bayonne New Jersey.

In order to minimize potential obstacles inherent with the original design EII redesigned the entire 13,000 lineal feet of leachate collection lines and pump stations incorporating the bio-polymer trenching methodology and a pneumatic pumping system:

• Stability of the existing cutoff wall during construction
  of the leachate collection system
• The need to dewater open trenches in order to install pipes
• Excessive volume of excavation and the need to construct
  work platforms
• Minimal slope of the gravity collection lines that would
  be future maintenance problems
• The ability of the containment system to provide an inward hydraulic
  gradient at the cutoff wall (i.e. leachate levels inside the
  cutoff wall lower than groundwater elevations outside the cutoff wall)

Approach:

The construction of the leachate collection system using conventional construction methods would have been financially, technically and environmentally unfeasible due to the identified design flaws. EII proposed an alternative solution, which solved the client's problems as well as saved the client a considerable amount of time and money.

Biopolymer Trenching with a Pneumatic Pumping System

A biopolymer slurry was used to support the walls of the 25' deep trenches where the perforated HDPE pipe was installed to a specified grade, before the stone aggregate was installed. A pneumatic pumping system was incorporated into the collection network in order to complete the leachate collection design.

These particular construction methods also minimized the nuisance of decomposed waste odors, which can emanate from open trenches in landfills. Additionally, since the pipes were laid at the bottom of the excavation by the integrated construction equipment, the workers' exposure to waste, leachate and landfill gas was minimized thus, improving the working conditions, during pipe installation.