Green Bin Organics Processing Facility Tour Dufferin Transfer Station February 26 th 2013

Dufferin Transfer Station, Toronto

I made it to the Dufferin Transfer Station, then made my way to the Source Separated Organics area

Overview of the anaerobic digestion system process CCI is the Canadian company with the license to use and distribute the German Company BTA’s equipment and anaerobic digestion system For more information, check out: referen0/toronto-dufferin.html

The Tip Floor Green Bin waste is brought into the tip floor. This is about 100 tonnes of Green Bin waste (a bit less than 2/3s of what gets processed in a day). Though it looks like lots of it is plastic, the bags are actually just a small percentage of the total weight.

The Pulper Green Bin waste get dumped into the pulper 16 tonnes at a time. The tank is then filled with water and then spun around at a high speed – this breaks apart the plastic bags and other plastic materials, and turns the organic* materials into ‘soup’. The spinning motorThe bottom of the pulper, where the ‘soup’ comes out * “Organics” in this case refers to any plant and animal matter.

Sorting out the ‘residues’ Once the organic matter has been turned into a ‘soup’, it gets drained out and pumped into the next tank. The plastic and other light materials get raked out of the tank, and ‘heavies’ fall to the bottom. Plastic bags get raked out of the pulper The ‘heavies’ fall to the bottom – metal cans, bones, batteries, glass…

Sorting out the ‘residues’, continued… All plastic bags, disposable diapers, pads, etc. get broken apart in the pulper. The organic matter breaks down in the water and turns into a ‘soup’. The plastics all float to the top and get raked out. Plastic bags (and other plastics) that have been raked out of the pulper. These get pressed together to push the water out and are then baled.

Grit Removal This part of the process removes any leftover small bits, like little bits of glass that could compromise the quality of the finished compost.

What’s going on here? The computer monitoring system of the organics processing plant The screen on the left is showing the grit removal tank. The screen on the right is showing the methane output levels in the anaerobic digester over the course of a week.

Temperature Regulation The bacteria in the anaerobic digester is mesophilic, so the temperature needs to stay at around 37-39°C. These pipes help regulate the temperature of the ‘soup’ going into the digester.

Anaerobic Digestion The ‘soup’ from the pulper gets pumped into the anaerobic digestion tank, where it takes about 21 days for the materials to break down. The tank on the right is the one currently in use.

Dividing the solids from the liquids After the anaerobic digester, the digester solids (organic matter) get pulled up through the screw press. The screw press is surrounded by mesh, so the liquid falls out and the solids get spun up to the top. The water gets reused in the pulper. The screw press from the outsideThe top of the screw press, with digester solids falling out.

Digester solids get taken to a compost facility Digester solids (organic matter that has gone through the anaerobic digestion process) ready to be shipped off to the composting facility. Digester solids get loaded into a container for shipping.

Methane gets burned off Currently at this plant, most of the methane gas gets burned off, while some is used to keep materials in the digester in constant movement. (At the new facility which is being built, methane will be used for power and/or heat.)

Inputs and Outputs The Dufferin facility processes on average 125 tonnes of Green Bin wastes per day. The chart below shows the outputs.

Finished compost Compost ready for use. This is composted Green Bin and yard waste material from Toronto, which has been taken to an out-of-town facility for composting, and is then returned to Toronto for use.

Proof that I was actually at the facility. In my most stylish outfit of the year.