Drehid Waste Management Facility

Drehid LandfillName:  Drehid Waste Management Facility, Contract No. 3, Landfill Cells Development Works.
Client:  Bord na Mona
Location:  Drehid, Co Kildare
Project Value:  €2.6m
Completion Date:  December  2009

Project Description:

The Project involves Site Development Works at Drehid WMF, Drehid, Co. Kildare.  These works include the construction of Phase 2 of the lined landfill, surface water management works and associated infrastructure to allow the acceptance of waste at the facility. Construction of 20,000m2 new waste cell. Lining of the new cell with specialist B.E.S and lining of new cell with specialist HDPE liner.

The cells area is 20,000m2. The excavation to formation level (4m deep) was carried out and the material that was excavated 80,000m3 was moved using A40 dumptrucks to another part of the site where it was used to fill a low part of the site and also create a bund around this area. At the start of the contract 20,000m3 of excavated earth from another part of the landfill was moved into this tip area. 

Once excavated to formation level a Type B Lining was installed in this case.  A type B liner invloves the installation of 500mm of a BES (Bentonite Enhanced soil) material over the area of the new cell. This layer is spread out using a dozer equiped with GPS to make sure that the levels are correct. The BES material is mixed on site. Testing was carredid out on this layer once it was in place to make sure that it confirmed to the standards set out in the contract. Once the liner was in place then the geotextile carpet was layed out over the cells. (this is a protection layer between the liner from the lechate.). 500mm of leachate stone was spread over the landfill area.

A leachate raiser pipe was installed and a leachate submerssable pump was installed in the new leachate collection sump. 100m of 90mm internal diameter (HDPE with fusion jointed pipes), 500m of 200mm (HDPE), 100m of 110mm (HDPE), and 155m of 560mm (HDPE) leachate collection pipeline was installed. All this pipework fed back to the existing leachate holding tank which were underground. New M&E equipment on the site for the lecahate collection system was installed.

New surface water swale drains were installed around the cell and this connected into the existing drainage system.
The supply and installation of new vertical gas wells in the newly constructed capped layer. The gas that was trapped in the first geotextile layer is collected via these vertical gas wells. Transport pipelines (HDPE welded pipe) were constructed to a manifold  and leachate knockout pot which in turn was connected to the existing gas flare. A new gas monitoring system was installed along with all the infrastructural requirements.

Additional Works Carried out:

The top soil was stripped from Phase 3 & 4 of Landfill and the construct of the embankments to Phase 3. These phase are currently out to tender.

The provision of all necessary documentation, manuals and training

Coffey Group, Athenry, Co. Galway, Ireland Tel: +353 91 844356 Fax: +353 91 844519 Email: info@coffeygroup.com