It is one of the world’s great ironies that with all the advancements in agriculture — which have had positive impacts on feeding people — that many still go hungry. At the recent summit on sustainable development in Rio de Janeiro, the UN Food agency reported that one in seven people on this planet still don’t get enough to eat.
It was also ironic, but more deliciously so, when Olivier De Schutter, the UN Human Rights Council’s “Special Rapporteur on the right to food,” made his May visit to Canada to investigate this country’s “unacceptable” rates of food insecurity that he didn’t take note of the great amount of food that ends up in the waste stream.
Organic waste (i.e., food and yard waste) continues to make up a significant part of our waste stream. Beyond unavoidable spoilage the organic waste that finds it ways to our curbs and bins could be the difference between food “security” and “insecurity,” never mind the environmental impacts that result from their landfilling.
On the single-family residential side, great strides have been made in swaths of the country; think Nova Scotia and Prince Edward Island and parts of New Brunswick, Ontario, Alberta and British Columbia. These provinces capture and mostly compost organic wastes. (Examples of current and possible future organics processing successes are included in the pictures that accompany this article.)
Even with these successes, the overall capture rate (of total food and leaf-and-yard waste) is about 25 per cent, assuming that it makes up about 30 per cent of the total waste stream. The diversion of organic waste is going to eventually hit a squishy glass ceiling of sorts, much in the same way that overall diversion has.
To date, overall waste diversion success largely resides with single-family households.
As available single-family household organics are captured we’re left with the more difficult-to-capture streams (using current source-separation approaches). This includes the multi-residential sector with which we continue to struggle on the dry recycling side (never mind organics and the IC&I), parts of which have flickering interest in organics diversion, but struggle with finding processing capacity and, in general, tend to gravitate to lowest-cost options.
We need to ask ourselves how far we want to go with organics diversion?
If we’re satisfied with current single-family and (some) IC&I organic waste diversion, then we need to go no further. However, if diverting organics from landfill is important we need to identify new approaches, to help us broaden the scope of organic wastes that we can collect (that is, move into multi-residential and commercial waste streams in a more meaningful way).
However if we believe that the environmental, never mind the social, impacts warrant a beyond-landfill approach, fundamental changes need to be occur.
In that case it’s time to take a hard look at the current paradigm, which is largely voluntary and exclusively focused on source separation.
The way forward includes new processing technologies that can produce energy, plus increasing our ability to handle more mixed and contaminated streams of organic wastes, with some level of regulation that limits or bans organic waste from landfills.
We often look to Europe for examples we should emulate.
The EU’s 1999 Landfill Directive’s purpose was to reduce to the greatest extent possible the negative environmental impacts of landfilling by implementing strict requirements for waste and landfill. It was estimated that thee per cent of the EU’s greenhouse gas emissions came from landfills. A key part of this Directive is that member states reduce the amount of biodegradable municipal waste that they landfill to “35 per cent of 1995 levels” by 2016 (for some countries by 2020).
This Directive does not prescribe how member states achieve these goals; this has resulted in different creative approaches by the various EU countries.
In the Netherlands, for instance, a combination of composting, anaerobic digestion and incineration has been used to essentially reduce landfilling to zero. The Dutch industry continues to integrate various technologies together at its facilities to offer the broadest possible set of solutions. (See example of Amsterdam Greenmills above.) This industry has been driven by the Landfill Directive and Dutch waste management planning at a national level.
In Canada there is body that could create a Landfill Directive like the one in Europe. The Canadian Council of Ministers of the Environment (CCME) long ago prepared publications on a number of environmental matters (e.g., CCME Composting Guidelines 2005). This would be the body to develop a Landfill Directive-like document for Canada.
The Province of Nova Scotia long ago banned organics from landfill and Quebec appears to be preparing to do the same. Nova Scotia’s ban spawned its robust composting industry.
Managing Mixed Streams
Twenty years ago there were great pretenders who promised that you could process a mixed waste stream and the compost end-products would be just like those produced from fully source-separated waste streams. However, as Shakespeare wrote, we learned you cannot make silk from a pigs ear.
The key with more mixed and contaminated feedstocks is to understand what can be can be done with them as opposed to what cannot. There are already hints of what this could look like in Canada.
The source-separated organics programs in Toronto, York Region and sometimes Edmonton have been criticized for allowing conventional plastic film bags to convey organics to processing facilities. While challenging, these facilities have shown it’s still possible to produce marketable compost while allowing bags.
If the stage was broadened beyond composting it could result in opportunities to process organic wastes found in the multi-residential and IC&I sector, as well residues from all sources. Newer approaches to dealing with these wastes include anaerobic digestion (AD) and mechanical biological treatment (MBT). These technologies that can better accommodate pre- and post-processing technologies to remove contamination.
New technological approaches
Anaerobic digestion, while not new, can be advantageous from a material-handling perspective. In systems where there-s wet pre-processing, there’s the opportunity to separate and remove contaminants for organic wastes. It’;s starting to grow in Canada.
The City of Toronto is currently building a 90,000 tonne/year anaerobic digestion facility adjacent to its current AD facility. This will allow that city to effectively remove contamination, more easily than from composting systems, from the broadly defined source-separated organics and allow the city to create biogas and ultimately compost.
Other AD facilities are under construction in Canada. For instance, Harvest Power is constructing anaerobic digestion facilities in both Richmond, British Columbia and London, Ontario. (See photos.)
Quebec also plans to invest heavily in AD facilities in the coming years.
Mechanical biological treatment (MBT) is a pretreatment method that can be used to treat mixed waste streams. There a variety of ways to set up this process. It can include separating out high caloric wastes and producing a refuse derived fuel product, plus digesting or composting a residue stream prior to landfilling or directing it to landfill.
In some ways the City of Edmonton’s centralized composting facility could be considered a MBT plant in as much as it receives a mixed waste stream (with recyclables collected separately), removes contaminants, and biological treats (i.e., composts) the rest. The difference is that it takes the process to
the production of compost. The Otter Lake facility in Halifax Regional Municipality is a clearer example of an MBT facility; that plant stabilizes residual wastes prior to landfilling.
In its more conventional sense MBT can be deployed to address the remaining residual streams such as single-family, multi-residential and IC&I residual waste streams. The process facilitates the removal of some recyclables and results in the biological decomposition of the remaining waste stream. In some cases a compost-like output (CLO) is manufactured. The remainder can then be landfilled.
MBT has been a key part of meeting the Landfill Directive for some European countries, such as Italy, and holds great promise for Canada. The key is to understand that it will not produce top-quality compost and perhaps not any product at all.
There are hints and actions that point to Canada’s next generation of organic processing. Freed from an exclusive focus on source separation and composting, these hints will, under the right circumstances (be they regulatory or other drivers) lead us to devise and employ new approaches that will allow us to capture benefits from a challenging waste stream.
Paul van der Werf is President of 2cg Inc. in London, Ontario. Contact Paul at firstname.lastname@example.org
Michael Cant is Principal and Canadian Waste Sector Leader for Golder Associates in Whitby, Ontario. Contact Michael at email@example.com