Landfill sites and in particular lining systems are complex engineering structures requiring detailed design and construction quality assurance.
Melton Ross, North Lincolnshire:
Initial hired operated plant has led to; Landfill capping operation and Principle contractor landfill cell base construction including:-
• Excavation (digging) down to the bottom of the sub-grade.
• Excess material (mostly clay) hauled to on-site stock pile.
• Quarry face dressed with a long reach excavator
• Rock trenches dug.
• Clay is re-compacted into 250mm lifts (layers).
• Clay packed down with both pad & smooth rollers. Each lift is then tested for optimal moisture and density.
• Cell is smoothed and surveyed.
• Edges of existing liner on adjacent closed cell are exposed and cleaned to join with new liner.
• Plastic cell liner is installed extending up sides of cell (polyethylene).
• Geotextile (permeable fabric) mat laid over the liner to protect it.
• Existing leachate pipe system (8-inch perforated PVC) is extended through new cell.
• Leachate is the liquid that filters down through the garbage, typically as a result of rain.
• Fines are hauled in and placed over liner and mat to a depth of 150mm on bottom and slopes of cell.
• Temporary berms with rain guards are built around the perimeter.
• The cell was then laid with tyre bails, placed by the use of a ‘forwarder’.
• As the cell is filled, wells built-up to capture leachate.
The biggest challenge of cell construction is usually the weather