Odour management

Mindarie Regional Council (MRC) is working closely with the Department of Water and Environmental Regulation (DWER) in response to community concern over odour. 

This page is regularly updated. Please keep checking back, here, for the latest updates and notices on odour management and relevant landfill operations from Tamala Park waste management facility.

About this page

Mindarie Regional Council (MRC) is responsible for the disposal of approximately 200,000 tonnes of household waste each year. That’s a lot of waste. In fact, MRC is one of the largest waste management authorities in Western Australia.

We work hard to minimise the impact odours can have on our neighbours, but this isn’t always an easy process.

This page is designed to answer some of the common questions about how MRC controls problem smells at our site and what we’re doing to improve our processes now and in the future.

Frequently asked questions

Why do landfills smell?

There’s no getting around it – when you put a lot of waste in one place, it smells.

Landfills are designed to manage the disposal of a large amount of waste in a relatively small area. This means there will always be a certain amount of odour from any landfill.

The smells we deal with at Tamala Park are largely from the food waste found in the nearly 60,000 residential red bins which are delivered to us each weekday, from seven local government areas.

Food waste can be particularly odorous. If you’ve ever found an expired carton of milk or forgotten tub of leftovers at the back of the fridge, you’ll know the kind of smells we’re talking about.

Those unpleasant odours are created as a byproduct of organic matter being broken down by bacteria and microbes.

What happens to the waste which arrives at Tamala Park?

There is a common misconception that a landfill is simply a large hole in the ground into which waste is dumped. In reality, modern landfills are very carefully engineered and operated to make sure that waste is properly and safely disposed of.

The household waste from our seven member councils arrives at Tamala Park in the same truck which empties your red bin.

First, that truck is weighed so we know how much waste is in it. Then it drives to the ‘active tip face’. This is the name we use to describe the area of the landfill which we are actively working on.

Once the truck has unloaded and left the tip face, the waste is compacted with an industrial heavy roller. If necessary, we then use natural odour suppressants and absorbents (like EcoSorb and zeolite) to minimise any smells from the waste.

At the end of the day, we use a thick layer of crushed limestone (known as cover) to seal the waste in and reduce odours.

What is leachate and how is it managed?

Leachate is the term used by the waste management industry to refer to rainwater which has travelled down through the top of the landfill and into the landfill mass.

As rainwater works its way slowly down through the layers of compacted waste and limestone, it mixes with the waste and picks up odours from whatever it encounters. It can take a long time for water to reach the bottom of the landfill. Sometimes it can become trapped in the layers and may not travel any further.

Leachate is often odorous, but the strength of the odour depends on how long it has been in contact with waste.

Managing leachate is important for a number of reasons, but particularly for minimising odour.

If leachate is allowed to accumulate for too long, it may create barriers in the landfill mass. These barriers are a problem during very rainy weather when fresh rainwater can’t drain down through the landfill and begins mixing with leachate and the fresh waste on the surface.

This can make our odour management techniques much less effective.

In Western Australia, most landfills use evaporation to manage their leachate levels. For most of Tamala Park’s 33-year operational life, leachate has been evaporated using lined evaporation ponds.

How do odours travel off site?

There are three types of odour associated with a landfill. These are: odours from fresh waste (on the surface); odours from decomposing waste (in the landfill) and odours from leachate.

Of these three, odours from fresh waste are the hardest to control and largely responsible for the smells experienced by nearby homes and businesses. Odours from leachate – which has a different smell to fresh waste – can also travel off site, but this is usually a more low-level odour and only noticeable at relatively short distances.

Unfavourable weather conditions - like winds which blow in the direction of nearby homes, or heavy rain - can make the smells from the landfill worse and make our efforts to contain them less effective.

In recent years, as the landfill has got fuller – and the profile of the landfill has got higher – the ‘crown’ (top) of the landfill, has become more exposed to the wind. This makes it easier for odours to travel greater distances.

Previously, when the level of the landfill was lower, odours would have been more easily trapped against the raised land around the site, or fresh waste would have been sitting low enough for the wind to travel straight over the top of it without transmitting any odours.

Another change is the amount of development around the Tamala Park site.

When Tamala Park was first planned in the late 1980s, the majority of the land surrounding the site was native bushland. However, in the 33 years which followed, many new residential areas have been built – some only 500 metres from the active tip face.

This situation has made controlling odours from Tamala Park much more difficult.

Are these smells dangerous to my health?

No. Although these problem smells are certainly unpleasant, they are not injurious in of themselves.

Through discussions with the WA Department of Health, the regulator (WA Department of Water and Environmental Regulation - DWER) has confirmed that the odours experienced by residents living nearby Tamala Park are not hazardous to human health. This conclusion supports MRC’s own findings on this matter and those of its independent consultants.

However, we recognise that the discomfort and inconvenience from problem smells are serious and real. That is why we’re working hard to minimise this issue as best we can. 

If you have any concerns about your health or wellbeing, please seek the advice of a healthcare professional.

What has MRC done to reduce odours?

Minimising odours begins with minimising the amount of waste sent to landfill. MRC and its member councils actively invest in initiatives to ‘divert’ waste away from landfill wherever possible.

If it cannot be diverted from landfill, we’re committed to disposing of your household waste properly and responsibly.

In line with the terms of our license, we compact and cover each day’s waste with limestone to minimise problem smells and prevent wind-blown litter. Since August 2024, we have increased the amount of cover we use in response to community concern about odours.

Since 2023, we have stopped accepting waste at night and stopped accepting commercial-scale odorous loads.

We have also reviewed and increased our use of natural odour eliminating compounds (like zeolite and EcoSorb) to minimise odours on the active tip face.

We recognise that more can be done to tackle problem smells. That’s why we’re investing in new and innovative techniques and trials, details of which we look forward to sharing with you soon. 

Why were odours more noticeable in winter 2024?

During late autumn and winter 2024, MRC received a lot more complaints about odour than usual.

In addition to the increased height of the landfill, the Tamala Park landfill – like much of the state - was affected by several consecutive days of heavy rain and strong winds. According to the Australian Bureau of Meteorology, the Perth metropolitan area received 62 rain effected days between June and September – the most for 28 years.

This resulted in the top part of the landfill becoming over-saturated with water, greatly increasing the levels of odour. This was exacerbated by a decision taken in February 2023 to pause the evaporation of leachate in response to community concerns over odour.

MRC recognises that the decision to pause the evaporation of leachate had a detrimental – but unintended – effect on odour management when combined with the exceptional weather conditions.

In response, MRC has taken several steps to remedy this situation, including increasing the amount of cover used on the landfill; pumping water away from water-logged areas and better use of natural odour suppressants, absorbents, and water treatments.

MRC is also investing heavily in new technologies and methods to improve our odour management practices.

We have also conducted a thorough review of our odour management practices and submitted a detailed proposal to the WA Department of Water and Environmental Regulation (DWER) which is designed to prevent similar events from taking place in future.

MRC is currently awaiting a response from DWER.

When will the landfill close?

Based on our current projections, we estimate that the Tamala Park landfill will close in 2028 or 2029.

Once the landfill has closed, we will begin the important process of completing the capping of the site, preparing the ground for planting and -finally – revegetating.

To ensure the site’s long-term safety and amenity, an environmental management presence will be necessary at the site for many years, post closure.

Why can’t the landfill close sooner?

When the landfill was approved by the WA Environmental Protection Authority in 1990, it was with to a very specific design. This is the design that we have been working with for the past 33 years.

Under that environmental approval, the landfill must be completed to a set profile – namely, a gentle hill which allows effective rainwater runoff. This is to stop pooling of water in the landscape, post-closure which could lead to long-term problems with leachate.

As of October 2024, of the 10 million cubic metres of space within that profile, only 1.2 million cubic metres remain. This means that the landfill is already well on its way to meeting its pre-approved design.

Closing the landfill sooner would not alter the need to have a profile which allowed for effective rainwater runoff, and it may be necessary to alter the existing profile to accommodate this need. Reprofiling could involve excavating large amounts of old waste which has been capped ‘sealed’ for several years. This would create a significant amount of odours, perhaps for months at a time. It would be almost impossible to control this odour using methods which MRC currently has at its disposal.

This is why we believe that completing the landfill to its original design is the quickest and least disruptive way to close the site in a timely and controlled manner.

How will Waste to Energy and FOGO affect the closure?

Energy Recovery (Waste to Energy/W2E) and Food Organics/Garden Organics recycling (FOGO) are already part of our projections for closure of the landfill in 2028 or 2029.

The MRC Council is progressing with plans for W2E and FOGO, currently.

Both W2E and FOGO are part of our long-term strategy to gradually reduce the amount of waste arriving at Tamala Park as we get closer to closure. This is because the final operational stage of the landfill is conducted in a much smaller footprint at the top of the planned profile and smaller volumes of waste are easier to control. In turn, this means it is easier to control odours at a time when the operational area is most exposed to the wind.

W2E and FOGO will allow the Tamala Park landfill to close in a timely and controlled manner and ensure that there is a long-term plan for waste produced by each of MRC’s seven member council local government areas.

How do I make a complaint?

We do our best to minimise any odours coming from our site, but we recognise that sometimes this isn’t enough to prevent their impact on your home or place of work.

All complaints are taken seriously and investigated. You will receive an automated response to your complaint within the hour and a more detailed response within two to three working days.

As part of our response to a recent increase in complaints about odour, MRC has set up the Odour Management Key Stakeholder Working Group. Your complaint will be passed on to this working group to help guide their work.

Meeting minutes from the working group can be found here.

---