Organic materials such as food waste that is disposed of in a landfill are a significant source of GHG emissions. In the absence of air in a landfill organics bio-degrade and produce methane gas that is a GHG twenty five times more potent than CO2. Forty five percent (45%) of Ottawa’s residential waste is organic material. In order to reduce GHGs and for Ottawa to meet its climate change objectives effort needs to be made to divert all residential organic waste from disposal.
Ottawa launched its organics waste collection program in January 2010 with the distribution of green bins to residences served by curbside collection. The service was not provided to the large number of apartment and townhouse units that are found in the city. This has meant that the potential for organics diversion and the reduction of GHGs that are associated with landfill disposal has not been achieved.
Poor and under-financed communication on the benefits of the program have also contributed to poor participation in the program and large amounts of organics that should be in the green bin have ended up in the garbage. City data show that almost 50% of what is currently collected as garbage should either be recycled or put into the green bin.
The poor performance of the green bin program has been complicated by controversy surrounding the “put or pay” contract that the city signed at the program’s outset for the material to be made into compost using an aerobic composting system. Under a put or pay contract the city paid to process a pre-determined tonnage of organics even though these tonnages were never reached, especially in the early years of the contract. A damning city auditor’s report documented the contract’s failings and the considerable over payment that resulted. Amendments to the contract which is held by Convertus (formerly Orgaworld, formerly Renewi) have been made to reduce the city’s financial exposure.
Expanding the green bin program to multi-residential buildings is essential to achieve the full potential of the green bin program and WWO supports the city’s decision to make organics collection a condition of city provided garbage service to all multi-residential complexes (See Multi-residential properties).
As part of the Solid Waste Master Plan consideration is being given to switching from the current aerobic composting system to an anaerobic digestion system that would produce bio-gas. The AD system could be linked with the system that currently produces bio-gas at the ROPEC waste water treatment facility.
Plastic Bags in the Green Bin
There continues to be concern about the quality of the compost produced and the level of plastic contamination that can largely be attributed to the city allowing the use of plastic bags for collected organics and dog waste. Also see Single Use Plastics in the Ottawa Green Bin
WWO Report on Organic Waste Diversion
April 19, 2020
A University of Ottawa MSc. Environmental Sustainability Capstone Project by Sara Hélène Dubé, Geniffer Emmanuel, Michael Hosken, and Edward O’Dea
“Waste Watch Ottawa (WWO) has asked our team to research the effectiveness of Ottawa’s residential organics waste management system compared to that of other Canadian cities, with a focus on the impact of plastics and dog waste on compost quality. First, in Part 1 background information is provided on the science and benefits of processing organic waste, as well as on implications and consequences of poor organic waste diversion. Organic matter can become compost through two main processes: aerobic or anaerobic digestion. The end-product can enrich soils if it is of good quality or pose environmental and health risks if it is not. Plastics (biodegradable or not) and dog waste are examples of threats to compost quality. Moreover, we explain that properly composting organic waste can reduce Greenhouse Gas (GHG) emissions.”