Composting Down Under: A Guide for Composting Toilets in Aussie Climates

Of course composting looks different based on where you are; we can’t provide the same advise to someone in the wet tropics of Cairnes, that we would to someone in the dry desert of Oodnadatta, or up in the snows of Thredbo. We have broken down our Australian climates into six main categories.

But of course there are likely to be exceptions to the rules. Like considering how cyclone season causes a flood in Lake Eyre which is one of the driest areas in Australia (based on yearly rainfall).

The high humidity and high rainfall in the tropics can slow the evaporation or drainage of excess liquids in comparison to the dryer climates. As a result we usually find that the composting toilets up north tend to be more moist

• • • Consider expanding the leachate drainage system to compensate for heavy rainfall and the ground being wet
    • Using the ventilation system to draw humid air out of the composting chamber
    • Increasing use of bulking agent to absorb excess moisture

It is also important to note that a wet composting system may also be more attractive to flies. So, it’s important to keep the ventilation running and keep the system closed (or using the mozzie stoppa when out-of-service) to help keep flies out. If you do start to see flies around your composting chambers, be sure to read A Guide to Composting Toilets & Flies.

These regions have mild winters so composting all year round tends to be a lot easier. The most important considerations are going to be maintaining moisture and oxygen within the composting system.

• • • You may find that bulking agent with a slightly larger particle size, like Wood Shavings, will allow more airflow through the composting pile
    • Prepare for the rainy season by maintaining a clean leachate drain, hot water will help dissolve any residue build up and make sure that the composting pile can maintain a healthy moisture level throughout summer

Now we are getting into the land of extremes – bushfire, drought, rain, and floods. Australian grasslands and woodlands are a kind of transitional climate zone because there are greater ranges in climate and rainfall, and they tend to exist between the subtropical and temperate regions. So it’s essential to be prepared for temperature fluctuations and maintaining moisture levels throughout the different seasons.

• • • Check local flood maps and bushfire attack level (BAL) ratings, this will affect where and how you would install a composting toilet considering the conditions
    • Compost piles tend to dry out in these conditions so adding moisture to the pile may help to keep a healthy composting pile

Characterised by the hot and dry air, composting in an Australian desert region means keeping a close eye on your moisture content. Compost microbes are living bacteria that won’t be harmed by the hot temperatures, but they will begin to go into hibernation if they become dehydrated.

• • • Consider keeping a small watering can or spray bottle on hand to moisten the composting pile when it looks too dry. It’s still less water than flushing a toilet!
    • Regular maintenance of the ventilation pipe to keep the fan dust free (same as you would need to clean off your solar panels)
    • As the temperatures drop during winter, the composting process slows down, so be prepared to swap out the composting chambers of batch style systems in this window of opportunity

The Clivus Multrum and Nature Loo tanks are built to last in the harsh Australian sun, but be careful of the stainless steel fittings that can get hot to touch!

The temperate regions in the south tend to have very different winter and summer periods. Which means you could be applying strategies for cold winters when the temperatures are low enough to hibernate the microbes and stop the composting process. But then in the summer months you can be combating hot dry winds.

• • • Similar to our desert advice, keep extra moisture on hand during summer to manage and maintain moisture levels
    • Consider the expandable capacity of a batch system where you are able to introduce an extra chamber into rotation to extend the composting time during winter
    • Reintroduce compositing microbes, by using Nature Quick Microbes or healthy compost from a previous batch, after winter to help kickstart a hibernating composting pile.

Undoubtably the hardest places to compost are in the alpine climates. In addition to difficult freeze-thaw cycles, the higher altitudes can also limit the oxygen to the microbes, so composting is going to be slow all year around.

• • • If the toilet is not in a heated room, consider reducing the fan speed to avoid drawing colder air into the composting chamber
    • Take advantage of the summer sun by placing out-of-service chambers in the full sun to help maintain a warm position for composting
    • Consider insulation around the composting chamber or installing a heat source to keep the chambers from freezing