From green bin to garden: how compost is made in the MODG

·6 min read

GUYSBOROUGH – The smell in building one of the new compost facility at the Guysborough Waste Management Facility (GWMF) on Highway 16 just outside of Boylston might turn your stomach when you first encounter it, especially on a day when containers of fish waste are being unloaded, but that’s all part of the process that ends with the best food for your garden: clean, rich compost.

Shane Cook, waste services coordinator at the GWMF, would be the first person to tell you that the smell isn’t always that ripe. As the decomposition process moves through time, the smell disappears completely, leaving only the familiar and pleasant smell of freshly tilled earth.

Cook has worked at the GWMF for 18 years and is clearly enthusiastic about the new compost facility that began processing organic materials a little less than a year ago. Before that time, composting took place on another site within the GWFM that was cramped for space and low on light.

The two new buildings — built at a cost of approximately $1.8 million, shared between the Municipality of the District of Guysborough (MODG), the provincial and federal governments – are made of galvanized steel with a translucent canvas top and are 80 feet wide, 200 feet long and 45 feet tall; the size of hockey rinks. The large space allows all the organic matter to decompose sheltered from the elements, with natural light to help fuel the process.

Cook says, “With compost you’re either too wet or too dry and you could never have any control [in the previous buildings].” With the new buildings, you take that uncertainty out of the equation and the processing time of raw organic waste to compost has shortened from approximately one year to eight months.

Building one is where all new material starts out, hence the smell. Two windrows of compostable materials rise on either side of the structure; one fresh organic and the other material that has already settled in for a couple of months. This building, Cook says, is the wet building and, after approximately four months, when material has time to decompose and dry out, it is transferred to the second building.

“There’s lots of reasons why we compost — greenhouse gas emissions are probably the biggest reason. Organic waste, if left in an aerobic state, generates methane. If you turn it and mix it, it generates CO2 and CO2 is a lot less harmful than methane. There’re other reasons too; people use it as a soil amendment, for erosion control, to keep soils alive,” says Cook as he surveys the changing colour of the organic materials in the first windrow, which indicates decomposition.

Composting, especially at this scale, is not simply a matter of letting organic waste rot. There is a chemistry to decomposition and over the years, Cook has become a master at determining when all the ingredients are at optimum ratios to produce the best compost.

“You need a carbon source with your nitrogen,” Cook says, eyeing the incoming fish waste. Once it dries out, it will be mixed with wood bark to create the balance required for decomposition. After that, it’s like the song says, “To everything turn, turn, turn.”

“You have to manage it like a pet. You have to give it water, you have to feed it. Then, after you start taking those things away, you know you’re on the edge to finishing,” says Cook, adding, “When you turn you’re giving it air but your also exposing new food.”

He points out that, although they take in a lot of cardboard mixed with the organic waste, after several months of decomposition, “You wouldn’t even know there was any cardboard here.”

The same is true of proteins — meat and fish — it all seems to have melted away after a few weeks. That disappearing act is facilitated by bacteria that feasts on that food and in the process creates heat—up to 60 Celsius in the windrow, which further increases bacteria production.

In the second building, the smell is earthy, not putrid. Birdsong fills the air, and the incoming light reminds one of a greenhouse.

In this bright, airy building, the finishing of the compost takes place — with a little more decomposition. In one windrow incomplete compost hosts a colony of mushrooms, which are secondary decomposers. Further down the row, towards the end where a white-looking ash has formed, Cook explains, “is the Goldilocks zone. It’s perfect air, perfect water and your organisms are that whole white seam, it’s where your bacteria are eating. They’re breaking down that material…so what I need to do at this point is screen it, add the water back in, then turn it a little bit more, and it will turn out like that,” he says, pointing to the screened, not yet ground compost. “A lot of work goes into getting it from this point to that point.”

When the GWMF started taking in organic waste for composting, the intake was 700 tons a year. “And right now, were doing 4,000 to 5,000 tons a year and this facility could handle up to 12 to 14,000 a year easily,” says Cook, adding, “Good to have space. Nothing worse than being cramped up.”

Cook walks over to a non-descript gray bundle next to the almost finished windrow and says, “Now there’s something I have trouble with — it’s a bundle of papers. You could probably read them. And there’s why they don’t break up. They’ve got this strap on them; I can’t even cut.”

Eventually the box cutter breaks through the twine and last winter’s specials on deli items appear.

“Isn’t that awful,” says Cook, “They’ll never break down like that.”

That’s an issue Cook has to contend with in self-sorted organics: garbage. By the time the compost is ready to go through the sorter, half of the finished pile is pulled out as garbage – plastic, bottles, etc. The rest goes to the new grinder that makes the finest compost Cook has ever produced.

The finished product is a dark silt that resembles ground coffee beans with a few larger chunks. And even at this stage, the pile steams when the front-end loader comes in to scoop up an order for a customer waiting outside in a pickup truck.

This is the point where customer relations take place, jokes Cook, “We’ll load 200 trucks in the spring, and everyone comes and talks.”

Cook typically gives people advice on how to use the compost, “Tips I use at home in my own garden.”

At $20 a yard, people leave the compost facility happy, with a tried-and-true product that will make their green thumbs that much greener.

And the process of turning waste into black gold continues, one green bin at a time.

Lois Ann Dort, Local Journalism Initiative Reporter, Guysborough Journal

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