Published on Monday, 24 November 2025 at 12:44:05 PM
Mindarie Regional Council (MRC) has submitted two applications to the Department of Water and Environmental Regulation (DWER) for works that are essential to closing the landfill, as planned, by 2028/29.
Without these works, it would be very difficult to close the landfill in a timely manner and in line with environmental best practice standards.
The proposed works address two important aspects of landfill closure:
- allowing final capping (sealing the completed landfill) to be undertaken within the existing landfill footprint; and
- allowing for the removal and reduction of landfill leachate (rainwater which has soaked through the landfill and mixed with the waste), which is currently hampering efforts to reduce odours.
The 2028/29 landfill closure date is a projection based upon the volumes of waste currently received at Tamala Park and on MRC having the necessary approvals to complete the landfill by that date.
Southern piggyback landfill cell application
A ‘piggyback liner’ is an impermeable barrier laid on top of an existing waste mass which allows more material to be placed above it.
At Tamala Park, a piggyback liner is required at this location to bring the area up to its final height and because the waste underneath does not have a liner of its own.
This dates back to a period in the 1990s when landfilling took place at Tamala Park in an unlined cell. However, unless the height of the land in this area is increased, it will be impossible to finalise the landfill to its final profile, which is required by the Department of Environmental Regulation (DWER).
Crucially, without a piggyback liner to separate the two waste masses, rainwater and leachate would be able to percolate straight down into the unlined waste mass and, potentially, into the ground below.
A piggyback liner will prevent this, allowing rainwater and leachate to be collected, managed and disposed of.
These works are a continuation of the approved landfill design which MRC has been working towards since 1990 and apply only to the existing landfilling area.
Importantly, this application does not extend the existing landfill footprint and is not designed to extend the life of the landfill.
‘Evaporation ponds’ application
Tamala Park is the only landfill in Western Australia which does not have permanent leachate management infrastructure.
Over time, this has allowed more and more leachate (the result of rainwater mixing with solid waste) to build up inside the landfill.
This is a big problem for two reasons:
- Odour management – leachate blocks the pipelines used to collect odours (landfill gas) and can even damage the machinery used in its collection and disposal (including the landfill gas power station).
- Final landform and rehabilitation – leachate suspended in the landfill prevents MRC from bringing those areas to final profile, which means we cannot shape, cap and rehabilitate them.
After exhausting all other options, MRC and its independent consultants have concluded that building permanent evaporation infrastructure at Tamala Park is the only option to reduce the amount of leachate in the landfill.
Numerous independently-led studies have shown that the odours experienced by those living close to the landfill come from landfill gas – not leachate. Odours from leachate are perceptible only at short distances and do not travel off-site to be perceptible beyond their immediate vicinity.
For more than 20 years (prior to February 2023), MRC irrigated and evaporated leachate across the full operational landfill area (approximately 13 hectares). The proposed leachate evaporation ponds are much smaller by comparison (approximately 3.5 hectares), but (by being permanently in place), will allow MRC to manage and reduce leachate much more effectively.
This, in turn, will improve odour management and allow for the closure of the landfill the projected date of 2028/29.
Why these applications matter and how you can help
These applications are essential to closing the Tamala Park landfill on schedule by 2028/29 and in line with environmental best practice.
Together, they will help MRC safely complete final capping within the existing landfill footprint, better manage leachate, and improve odour control for the surrounding community.
If you support these goals, you are encouraged to contact the Department of Water and Environmental Regulation (DWER) to express your support for MRC’s applications.
ENDS
About MRC: Mindarie Regional Council (MRC) is one of Western Australia’s biggest waste management authorities, providing a comprehensive waste disposal service to local government authorities and residents in the Perth Metro Area.
For more information, visit mrc.wa.gov.au
Information for media: For enquiries relating to this release or any other questions from journalists regarding MRC, please contact communications@mrc.wa.gov.au or call 0417 252 227.
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