Sunday, May 10, 2009

The Green Bin Debate

This year at our school we started a composting program. The horticulture teacher had already been composting plant material, so it wasn't that hard to add on the rest of the picture - and it makes for better compost too. At home I compost veg matter and plant waste in one area, but I also have a "green cone digester." They were popular about fifteen years ago, but have all but disappeared along with home composting when environmentalism lost favour. A digester will take meats and dairy that can't go in the composter. Actually, we started using it again mainly to accommodate the waste from our new dog, Jack. The waste in a digester is decreased with microbes, then after a year or two of use (or five from my experience), the cone gets relocated and anything left over is buried.

This is Jack, and he makes a lot of "waste." In Canada it's illegal for any feces to go into the landfill. That means that disposable diapers are supposed to be scraped clean before being tossed. It also means we shouldn't bag the dog poop and dump it in the garbage. Just because most people do it, doesn't make it okay. I'm not always a rule-follower, but there's some really good reasons for keeping feces out of the landfill - it's a breeding ground for bacterias. The green cone - or solar cone - reaches high enough temperatures to kill off the bacteria. In the landfill it's all just mummified.

But what happens when feces and meat and other kitchen scraps go into the green bin? It certainly takes a lot of waste away from landfills. That's great! But where does the waste go, and is it preferable than using home or community composting areas? To me, it's a no-brainer that we can save the landfill space AND save the environment better if we each deal with our own garbage locally. But I could be wrong.

First of all, where does it go? In K-W, the green bin waste is shipped to Thorold, Ontario, near St. Catherines. So we're increasing the amount of greenhouse gasses produced in the movement of our garbage because part of it is being shipped a longer distance. This doesn't begin to look at the financial costs involved in the transportation.

Secondly, what happens to it? The film Garbage! has a great little clip of what happens to organics from a green bin program. They're heated up to get rid of any bacteria, then all plastics and non-compostables are spun out of the mix and sent to the landfill. So even if you use a corn-starch plastic bag for your dog poop, the bag might still end up landfilled. And nothing in the landfill decomposes, even compostables, because it's all stacked and buried. But if a bag gets missed, it's not a big deal for the operation if it's not plastic.

But most disconcerting, what happens to the end result? The green bin product isn't really compost proper, it's bio-solids. What makes the difference is the addition of meat, dairy, and feces. If you want to add nutrition to your garden, you want manure from herbivores: cows and sheep mainly, and broken down plant matter. There's a host of problems created if we add manure from carnivores or decomposing meat because they're more likely to host E. coli and other pathogens and contain heavy metals. And some of these might not be totally destroyed by heat.

If pathogens are present, it's not a problem if it's buried in small quantities away from the water table. It is a problem, however, a big problem, if the product of the process is used to fertilize agricultural land. In Thorold it seems they sell the product back to the consumer. It may be great for the flowers, but I'd keep it off the vegies.

A great book, The Big Necessity, by Rose George, talks at length about the growing practice of using carnivore manure (that's us), or sludge, to fertilize agriculture. And it links it all to growing illnesses.

So here's the thing: Do you think it's better to convince a municipality to divert its own waste through composting and green cones, or through a green bin? What would it take for most people to be willing to deal with their organic garbage themselves or communally? And do you think it's safe to use the green bin compost on food?


1 comment:

Anonymous said...

Green bin program costs too much?
Not always.
What would happen if we switch weekly collection to monthly collection?

There are solutions.