Case Study:  Horizontal Well Collection Efficient Method of Landfill Gas Collection

The EarthRes Solid Waste Engineering team has compiled a white paper demonstrating the effectiveness of horizontal well collection versus vertical well collection of landfill gas.  Co-authored by EarthRes Director of Solid Waste, David R. Horvath, P.G., Project Manager, Samuel A. Dean, and Staff Scientist, John D. Bechtel, this paper is a study on the successful historical performance of horizontal wells installed over an eleven year period.  Their findings illustrate that horizontal well collection can be effective enough to forgo or reduce and delay vertical well installation until final capping and closure.

Cost Effective Collection Method for compliance with Federal and State Emission Requirements

As the third largest source of methane emissions in the US, according to the US EPA Landfill Methane Outreach Program (LMOP) website (http://www/epa.com/lmop/basic-info/index.html#a02) the Code of Federal Regulations, Part 60 requires that owners of municipal solid waste landfills MSWs with capacity of equal or greater than 2.5 million megagrams or greater than 50 megagrams per year install gas collection and control systems.  Some states also have secondary requirements that landfill gas collection be collected to convert to direct use or for electricity generation.

Vertical gas wells, the “industry standard” have some inherent problems with active waste disposal areas; areas where horizontal well collection can excel and provide great benefits but is an under-utilized technology due to perceived durability or longevity issues.  While each application is unique and there are design considerations, horizontal gas collection can be a cost effective and ideal method of collection.  It can alleviate gas collection issues due to vertical well tilting, and rapid production rate decreases due to piping system integrity, liquids accumulation, and differential pipe settlement as the landfill approaches final design grade.

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