Are your landfill gas condensate or leachate force mains experiencing higher than expected pressures? Excessive clogging? Lower than expected flow rates? If so, it’s likely that your landfill liquids conveyance pipe network could use some attention and perhaps a reconfiguration.

While landfill gas (LFG) well spacing and depths are carefully designed to provide adequate LFG extraction coverage and to limit the potential to damage the landfill liner system, design of the pipe network to convey LFG condensate commonly receives less attention during design. At many sites this results in the pipe network receiving a lot more post-construction attention than desired in operation to keep it working properly in the form of cleanings and replacement of clogged sections of pipe.

Solutions to keep landfill liquids flowing are multifaceted, and include proper design, careful installation, and routine maintenance. For one example, design force mains to drain between pump cycles, and to flow with appropriate scouring velocities when pumps operate. While the concepts are relatively straight forward, as usual, execution is another matter, particularly when using low flow pump systems.

If you’d like to learn more about keeping the landfill liquids flowing, read the recently published article “Keeping Landfill Liquids Flowing” in the March 2022 issue of EM magazine, the Magazine for Environmental Managers, for a more in-depth discussion.

This article appears in the March 2022 issue of EM Magazine, a copyrighted publication of the Air & Waste Management Association (A&WMA; To learn more visit

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Written By

Jim Chabot, PE

Vice President

Jim has returned to Sanborn Head with over 30 years of experience on a broad range of engineering and construction projects.