Mindarie Regional Council lodges key applications to support closing its Tamala Park landfill by 2028-’29
A waste management authority in the northern suburbs has applied to carry out works to close the landfill at Tamala Park by 2028-29.
Mindarie Regional Council has submitted two applications to the Department of Water and Environmental Regulation.
The council says without the works it would be difficult to close the landfill in a timely manner and in line with environmental best practice.
The works will allow for final closure of the landfill footprint (closure of completed landfill).
They will also allow for the elimination and reduction of landfill leachate (rainwater that seeps into the landfill and mixes with waste), which currently cripples efforts to reduce odors.
The 2028-2029 landfill closure date is a projection based on waste volumes received at Tamala Park and whether MRC has the necessary approvals to complete the landfill by that date.
The Tamala Park landfill will require an ‘overlay liner’, which is an impermeable barrier laid over the existing waste mass, allowing more material to be placed on top.
The liner needs to bring the area to its final height, and the waste underneath does not have a liner of its own.
This dates back to the 1990s when landfilling took place in an unlined cell in Tamala Park. However, unless the land height in this area is increased, it will not be possible for the landfill to reach the final profile required by the Department of Water and Environmental Regulation.
More importantly, without a piggyback liner to separate the two waste masses, rainwater and leachate will be able to seep 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 that MRC has been working on since 1990 and apply only to the existing landfill.
Tamala Park is the only landfill in Western Australia without permanent leachate management infrastructure.
Over time, this led to the accumulation of more and more leachate (rainwater mixed with solid waste) within the landfill.
This is a big problem for two reasons:
Odor management – leachate clogs pipelines used to collect odors (landfill gas) and can even damage machinery used for collection and disposal (including landfill gas power plant).
Final landform and rehabilitation – leachate suspended in the landfill prevents the MRC from bringing these areas to the final profile, which means we cannot shape, cap and rehabilitate them.
After exhausting all other options, MRC and its independent consultants concluded that building permanent evaporation infrastructure at Tamala Park was the only option to reduce the amount of leachate at the landfill.
Numerous independent studies have shown that the odors experienced by those living near landfills come from landfill gas, not leachate. Odors from leachate can only be detected over short distances and do not travel off-site to be detected beyond the immediate area.
Over a 20-year period (before February 2023), the MRC irrigated and evaporated leachate across the entire operational storage area (approximately 13 hectares). The proposed leachate evaporation ponds are much smaller in comparison (approximately 3.5 ha), but (as they are permanently in place) will allow the MRC to manage and reduce leachate much more effectively.
This will improve odor management and allow the landfill to be closed by the projected 2028-’29 date.
The two applications will help MRC safely complete final closure within its existing landfill footprint, better manage leachate and improve odor control for the surrounding community.
If you support these goals, MRC encourages the public to contact the Department of Water and Environmental Regulation to express their support for the practices.
