Green Bin Program... From curb to compost
Step 3: Anaerobic digestion
This step takes place in the anaerobic digester, a sealed tank adjacent to the receiving and processing building.
The anaerobic digester creates the necessary conditions for naturally occurring anaerobic bacteria to partially break down the organic materials.
In approximately 20 days anaerobic bacteria consume the liquid pulp and convert it into:
 |
Digestate: an organic solid material; and, |
 |
Biogas: a renewable energy source. |
 |
Biogas is a combustible mixture of methane and carbon dioxide and is a renewable energy source. The City plans to make use of the biogas either through co-generation or a biomethane system. |
| Hamilton (Digester Gas) Cogeneration Project Hamilton Renewable Power Inc. in partnership with the City of Hamilton's Water and Wastewater Division of Public Works |
|
 |
| City of Toronto, Dufferin Organics Processing Facility |
- Roughly, 110 cubic metres of biogas is produced from one tonne of organic waste, equivalent to 670 kwh of energy.
Excess water is squeezed out of the digestate to prepare the material for transfer to a composting site.
What about odour?
Exhaust air from the receiving and processing buildings' ventilation system is passed through a biofilter to remove odour and dust.
- A biofilter is made up of organic materials such as wood chips and compost.
- Bacteria living on the compost and wood chips remove odours by consuming the compounds in the building air that make it odorous.
 Previous Page |
 Next Page |