"The Dirt" on Yard Waste Composting

Have you ever really thought about what happens to your yard waste after it gets picked up at the curb? Or what about the loose leaves that are collected on the roadside in Burlington and Oakville?

Where does it go and what becomes of it? Well you may be surprised to learn that only 6-8 months from the day you put yard waste at your curb, it is transformed into dark, rich compost.

This is what the 13-acre compost pad looks like from above, as Xena would see it!

The Halton Waste Management Site, located at 5400 Regional Road 25 in Milton, is home to a 13-acre composting operation, where all of Halton Region’s yard waste from your curbside collection and resident drop-offs is processed.

Within a few days of arriving at the site, the yard waste is grinded into smaller pieces and placed into long rows, called windrows, where it stays for a few weeks at high temperatures. Front-end loaders pick up the compost and turn the massive piles once every couple of days, in order to keep the temperatures in the piles around 55°C (131°F).

After the a few weeks, all naturally occurring germs — called pathogens — are killed off because of the high temperatures. On a cold day, you can see steam rising from the windrows, the piles are so hot!

The grinded yard waste is then flipped routinely with the front-end loader allowing the material to “cure“ or stabilize.

Leaves, sticks, twigs, decorative cornstalks, fallen fruit from trees, yard and garden trimmings and pumpkins - it all goes in your yard waste!

This time of year the compost pad is jam-packed with all of your yard waste and leaves, prepping for old man winter!

Believe it or not, there are only 3 ingredients needed in order to have successful composting operations: air, water moisture and yard waste!

Tiny micro-organisms like bacteria, fungi and single-cell protozoa eat the food (yard waste) and rely on the oxygen in the air to thrive aerobically. With all the micro-organisms eating away at the yard waste, the temperature in the windrows can heat up between 60°C and 70°C, even in the winter! The micro-organisms also needs a moist environment to effectively breakdown the ground yard waste, so the windrows are often irrigated in the dry summer months from a nearby storm water pond.

The nearly finished compost is then sent up a conveyor belt into a screener machine to separate the fine finished compost from large pieces that still need to breakdown and any plastic contamination. The larger pieces of compost are placed back into the windrows to finish breaking down, and any plastic gets sent to the landfill — that’s why it’s very important to not put any plastic in your yard waste.

A front end loader flips the piles of compost to let the oxygen in. The piles are so hot, you can even see the steam!

Plastic was first banned from yard waste in 2003, when paper bags and reusable rigid containers were implemented.

All of the finished compost that meets the regulations as set by the Ministry of the Environment is then ready to be used in yards and gardens. The compost is best mixed with topsoil at a ratio of approximately 40% compost and 60% topsoil.

Twice a year, the Halton Waste Management Site holds a free compost give away, to thank all the Halton residents for diverting 32,000 tonnes of yard waste from the landfill.

From your home as yard waste and then back to your yard as compost, thank you for doing your part to help with waste diversion!