Dr. Paul Arnold: On the chewing (and cutting) edge of composting technology

Dr. Paul Arnold’s research is on the chewing (and cutting) edge when it comes to composting.

Although not his primary focus, Arnold has had an ongoing hobby looking at how worms can be used in the composting process. He began his career with National Sea Products in its engineering department, investigating the management of fish waste. Originally, the fish by-products were diverted to a landfill or back to the sea, but when policies changed, Arnold was asked to find new ways to process the waste.

Thus began his interest in compost and waste management, and a realization that waste could be a marketable commodity.

A faculty member in Acadia’s Ivan Curry School of Engineering, Arnold retains an abiding interest in waste management, looking at ways to optimize microbial growth to enhance and speed up the composting process, and this is where worms come into the story.

For decomposition to happen, three things are necessary: air, food (for the microbes), and water. Worms are like tiny gardeners whose activities aerate soil. Without worms, people would have to manually turn soil to let oxygen in to support microbes or it would have to be done mechanically.

Biology student Jonathan Howatt (’13) worked with Arnold and his worms for his honours thesis. Howatt wanted to test if levels of carbon dioxide affected the growth rate of plants. To do so, he used planted pot trays encased in a plastic tent. Under one of the trays was a box of composting worms. Results indicated that the plant tray containing the worms had higher levels of carbon dioxide, which initially accelerated plant growth.

Real-world applications

Not a lot of pure research is being done on composting or especially the use of worms, Arnold says. “Farmers know of the benefits of using worms, but it is a relatively new topic for study.” Acadia, it seems, is on the “chewing edge” of this kind of research.

The use of worms in composting – known as vermiculture – has many real-world applications, especially in terms of waste management. If composting facilities employed worm aeration, they might be able to do away with expensive equipment like loaders, which are currently used to turn compost piles in the later stages of decomposition.

Arnold says his lifetime research goal would be to look at the heat energy given off in the initial decomposition stages. “If we could capture the energy from composting, we could use it to run a nearby facility, such as a greenhouse,” he says.

This process would involve researchers who have expertise in optimizing compost decomposition, growing plants and operating a greenhouse. Arnold has partnerships with the Northridge Farms compost facility near Aylesford, Nova Scotia, and Valley Waste Resource Management in Kentville.

Compost guru

“Paul is known as the compost guru to us solid waste folks,” says Andrew Garrett (’98), communications manager at Valley Waste.

Garrett says Arnold and his students have worked on several solid waste projects that have helped municipalities find solutions for hard-to-manage materials.

“His expertise on compost systems is an invaluable asset to Nova Scotia's organics management programs,” Garrett notes.  

If anyone is interested in learning more about worm composting or seeing it in action on campus, Arnold says people are welcome to contact him directly at paul.arnold@acadiau.ca. He has also made presentations to schools or groups with a special interest in composting.

“I’m so pleased with Acadia and its attitude toward waste management and the environmental initiatives it is taking,” Arnold says. “Through programs like Environmental and Sustainability Studies and the Acadia farm, we are making headway toward conserving our resources, and I’m happy to be associated with it.”

Written by Laura Churchill Duke (’98)

Originally published in the Bulletin, Spring 2016.


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