The Myth of "Residual Waste"
A look at what's in that "final third" of the waste
Recently, I was asked by my good friend John Nicholson (a consultant and
contributing editor to this magazine) to address a meeting of the Air and
Waste Management Association (AWMA) Ontario Sector, regarding my position on
generating energy from "residual waste."
This invitation provided me with the opportunity to research the
composition of so-called residual waste -- you know, the roughly 35 to 40 per
cent (depending who you talk to) of residential waste that's left over after
blue box recycling and source-separated "green bin" composting.
Luckily, the Regions of York and Durham (just outside Toronto) have, as
part of their recent EA process, modeled what would remain in (what they
label) the 40 per cent of waste after maximized diversion. The results --
what's in that final 40 per cent -- are as follows.
Almost a fifth (17.2 per cent) is material that wouldn't even burn,
including metals (13.3 per cent) and glass (3.9 per cent).
Another almost fifth (18.1 per cent) is food that on average (we're told)
contains between 70 and 80 per cent water. You don't get much energy from
burning water, last time I tried. (See for yourself; tonight, build a small
fire and then throw dinner on it to see what happens.)
To continue, there is 4.3 per cent in leaf-and-yard material (easily
composted). Rounding out this group are HHW (0.3 per cent, and stuff you most
certainly don't want to burn) and textiles (2.4 per cent -- also
something that'd be nice to not burn).
Taken together, all of the above totals 42.3 per cent of the "residual
waste" -- stuff that either won't burn or that we should not burn.
This helps explain why waste-to-energy plants are so inefficient and why
the small amount of power they produce is so expensive.
So, what remains?
First, there's the paper/fibre category, more than a quarter of the total
(26.6 per cent). This has two sub-categories; recyclable (15 per cent) and
non-recyclable (11.6 per cent). Obviously we could recycle the "recyclable"
paper/fibre. What about the non-recyclable sub-category. It's described as
compostable paper and sanitary products. As with food scraps, I wonder just
how much energy can be generated by burning a soaking wet diaper and why we
wouldn't compost the "compostable" paper.
What am I missing here?
Within the all-important plastics category are: recyclable plastic (3 per
cent), film (2.5 per cent) and mixed plastics (6.8 per cent) for a total of
12.3 per cent.
Note that combined the paper fibre and plastic categories total 40 per
cent. Now, imagine if by reduction, packaging legislation, reuse, stimulat- ed
via taxation, simple separation for recycling (and, of course, market
development for this recycled material) we could divert two-thirds of the "40
per cent residual waste." What would we be left with?
Just 13.6 per cent of the original 40 per cent of the paper/fibre and
Is it really worth building a mass-burn incinerator or a new-fangled (and
expensive!) gasification plant to address that tiny fraction of the waste
stream? I think not.
To say we have "maximized diversion" (at 60 per cent) is, to me, false.
Like any other product or service we have non-users, light users, medium users
and heavy users of diversion, and there is much more we can do to move
residents onward and up this continuum. As I like to say, if can get people to
eat at McDonalds, we should be able to get them to do anything!
And remember, we now know have a great reason when recycling a tonne of
paper and plastic recyclables; recycling them eliminates two to three tonnes
Okay, so now what's left?
The last, rather large category (18.6 per cent) is called "combustible
material" which is described as building renovation material, miscellaneous
goods and other material.
Imagine, again, if by Internet exchanges, depots, a fourth stream of
collection and return-to-retail we could reduce this category by two-thirds,
leaving us 6.3 per cent of the original 18.6 per cent. Add to this the 13.6
per cent in paper fibres and plastics, and I'd argue we have 20 per cent of
the so-called "residual waste", or just eight per cent of the total waste
stream to deal with as residual, not the 40 per cent that many wish
which to burn.
Just eight per cent.
Rod Muir is Waste Campaigner for Sierra Club Canada and founder
of Waste Diversion Toronto in Toronto, Ontario. Contact Rod at