Presenter: Phil Landmark, MWH
Presentation title: Levin landfill – lessons learned and progress made
Levin Landfill – Lessons Learned and Progress Made Levin Landfill, like many landfills, has had its challenges. Unlike most landfills, however, it has been subject to an investigation by the Parliamentary Commissioner for the Environment (PCE), and the review of its resource consents was closely scrutinised by the Neighbourhood Liaison Group (NLG) during a protracted process. Nevertheless, in tackling the challenges, the Horowhenua District Council has learnt valuable social, technical and financial lessons. This paper explores the lessons learned and provides comments and information that will be of use to landfill designers, owners of landfills, and especially territorial local authorities who own and operate landfills within their districts. Interaction, often vigorous, between the NLG and the Council resulted in the development of a mutual respect, though not necessarily common agreement. The NLG and the Council form the basis for a working party, which meets regularly. The PCE report highlighted technical issues that required the re-design of moderately steep side-slopes. This has led to a change in design whereby the side slopes will be benched, and a confining layer constructed over the geocomposite liner, which is supported by a geogrid. In considering the need for re-designing the side-slope liner, the Council undertook a unique investigation approach. The exposed side-slope liner system was cut open to identify any issues associated with the previous design, for instance, shifting of the underlying geosynthetic clay liner (GCL) panels due to a lack of confinement, or dehydration of the GCL. Additionally, a trial confining layer was constructed on exposed side-slope liner to prove the viability of supporting it with geogrids. Whilst the landfill site would not “tick all the boxes” for siting a landfill in terms of the CAE Landfill Guidelines, the Council had chosen to continue with its existing landfill asset and operate it in accordance with “good practice”. Whilst not required by regulation or resource consent, Council has chosen to construct a landfill gas collection system and is in the process of installing a new flare. The Levin Landfill is an asset to Horowhenua District Council and provides financial benefit when compared to other available disposal options, such as exporting waste out of the District.
Event: WasteMINZ Conference 2013
Date: Thursday 24 October 2013