Landfill Gas Extraction Trials...

On instructions from Bedfordshire County Council, RLCL developed the design and environmental control systems associated with the capping and remediation works to Sundon Landfill site. 

The capping and remediation works will include the complete upgrading of the landfill gas management system over a two to three year period.  This will pose considerable operational difficulties and it was essential that an alternative collection system is developed to ensure the continuity of landfill gas extraction. 

The objective of the gas extraction trials is to compare the effectiveness of using vibro-inserted Permavoid vent nodes and Permavoid wall assemblies with a typical retro-drilled borehole system. The trials will also identify the most cost effective configuration of vent nodes or wall assemblies which have not previously been used for this particular application. 

The trials will assess the advantages of the geosynthetic system which are likely to include:- 

• Gas transmitting into a vent node or wall system more efficiently than into slotted pipes due to their high surface/void ratio;
• Gas being more effectively harnessed through a vent node or wall system;
• Installation time and costs being substantially reduced;
• Vent node or wall system withstanding high fill and traffic loads; and
• A larger radius of influence of each Permavoid assembly.

Two existing gas producing boreholes were selected as the control points.  The assemblies were installed and the trials are being carried out around these boreholes.  The project is managed by Ray Trott.

Permavoid Vent node and wall assemblies