Leachate Treatment

Leachate Collection

Leachate Lagoon

Leachate Lagoon

During the construction phase, a leachate collection system comprising leachate drains and collection sumps, was installed. Leachate generated in the cell percolates through the waste and is collected in a 500 mm drainage blanket which is placed on the HDPE liner and perforated 200 mm and 150 mm diameter collection pipes. The base of each cell is graded and comprises a very low hydraulic conductivity so that leachate generated in the cell will drain to the collection sump.

The leachate level in each cell is maintained below a depth of 1 metre above the HDPE liner level to minimise the risk of overtopping the cell wall and also reduce the potential for permeation and leakage through the lining system. Leachate levels in the cells are controlled by pumping accumulated leachate either to the leachate storage lagoon or the Leachate Treatment Plant.

Leachate Transfer

Leachate is pumped from the leachate collection sumps in each cell to either the leachate storage lagoon or the storage tank (LT3) in the Leachate Treatment Plant using submersible pumps and a system of underground pipework. The pumps are activated either automatically by a level control mechanism, or manually. The pumps are linked telemetrically to the SCADA monitoring system in the Administration Building.

Leachate Storage

A pipework system, comprising separate feed and return lines, has been installed between the new 6,500m3 lagoon and the Leachate Treatment Plant to provide flexibility for transfer of leachate. Leachate from the lagoon is managed by:

  • Transfer off-site by tanker for disposal to public sewer
  • Transfer to Leachate Treatment Plant

Leachate Treatment

Leachate intended for treatment is stored temporarily in the Storage Tank (LT3) prior to being pumped to the two Aeration Tanks (LT1 & LT2) where it is currently aerated for a period of 16 hours. Treatment comprises of an activated sludge digestion process for the nitrification of leachate. Treated leachate is then pumped to the Balance Tank from where it can be:-

  • Taken off site by tanker
  • Pumped to the Leachate lagoon for collection by tanker
  • Discharged to Local Foul Sewer via rising main to Kill.

Leachate Disposal

Leachate removed off-site either directly from the leachate lagoon, or from the Leachate Treatment Plant after treatment, is transported by tanker to a public sewer at Saggart or discharge to local sewer.

  • From the Gallery…

    Testing of the placed Clay Liner at Arthurstown 2 Weighbridges at Arthurstown Arial - Arthurstown Landfill Arial - Arthurstown Landfill