The natural process that transforms organic kitchen waste into rich, dark compost is a long one in a regular backyard composter. The advanced method used at the City of Hamilton’s Central Composting Facility is so efficient that after about 2 months the “black gold” is ready to be used to enrich soil.
There are two phases to this accelerated process. In the first phase, unwanted debris is removed from the organic waste that has been collected by Hamilton residents in their green cart and then it is ground up and loaded into one of 10 tunnels. It remains in this carefully regulated environment with ideal heat, humidity and temperature for breaking down the material for seven to 10 days.
When phase one is completed, it is loaded into one of six phase two tunnels. The volume of the organic waste has been reduced by 45 to 50 per cent during the first phase. Like the phase one process, the phase two process takes from 7 to 10 days.
During the second phase, according to Dennis Guy, project manager of Waste Management, “You don’t want anything dirty in contact with it.” At this point the compost is being pasteurized, meaning it’s being cleared of any pathogens and unwanted bacteria, he explains. It’s exposed to only clean water, clean air and clean loaders.
Before the compost is ready to be sold, it passes through a star screener equipped with long spikes that turn like cogs. Pieces that are too large, called “overs”, are collected and put back into the beginning of the process.
There’s another trip through a magnet that will catch undesirable materials. After a visual inspection, the pasteurized compost travels on a conveyor-like tube to the curing building where it sits for about a month. It’s sold by the truckload to customers like commercial nurseries.
Guy explains that a bio-filter decreases what would otherwise be the strong odour associated with rotting food waste. The bio filter is a large room filled with woodchips. After the filtering process, the exhausted air “smells like a forest floor after a rain”. When the woodchips need to be replaced, the used ones go into the system to be composted.
Small groups of students get to go behind the scenes as part of a popular educational program offered by waste management.
To find out more about the City of Hamilton’s composting programs, visit
www.hamilton.ca/waste.
