Methane Extraction System
NERC, Middlesex County, New Jersey
Project Description:
Edgeboro International, Inc. was retained by the NERC Middlesex Gas Company to construct three methane extraction systems at the Edison, ILR and Middlesex County landfills.
Due to a distinct differentiation among sites, each facility was evaluated individually taking into account the age of the facility, the type of waste collected, time of closure, existing and proposed environmental controls, and the location. Further information was obtained by performing pump tests, which established the area of influence and the approximate quantity of gas that could be captured from a given area in the landfill.
Approach:
Edison
The Edison municipal landfill is a closed and uncapped landfill located in Edison, New Jersey. The methane extraction system was designed to accommodate future environmental controls that would be necessary for the proper closure of the landfill. The system was installed with modified wellheads and a collection system that could be easily sectioned, and quickly dismantled and reassembled without having to shut down the collection system.
ILR
The ILR landfill is a closed and capped facility also located in Edison, New Jersey. The landfill was found to have a very dry waste composition, which is not optimal for gas production. EII resolved the problem by designing the system in a way to hydrate the waste composition which increased gas production.
MCUA
The Middlesex County landfill is an operating facility presently landfilling approximately 400,000 tons per year in East Brunswick, New Jersey. The design and construction of this particular methane collection system required special attention to avoid disrupting the daily activities of the ongoing landfill operation. To accomplish this, the system was designed and installed in a manner that would allow the entire system to later be buried by waste.
Unlike most conventional collection systems, which are usually installed on the surface after the landfill is closed, this system would not be able to be repaired at a later time should a failure occur. Therefore, it was required that further precautious factors be built into the design to take into account the additional forces that would possibly cause the system to fail.
For example, the tremendously uneven settlements that take place within a landfill, caused by the fluctuating decomposition rates of different waste systems and varying compaction levels of the daily operation, could later crush the wellheads, kink laterals and disrupt pipe grades for drainage. To overcome this condition, exaggerated grades and drainage with additional expansion and compression points allowing for 10-15 feet of settlement were factored into the laterals as well as the wellheads.