Tag Archives: vermiculture

Vermicomposting in the SUB

by Emme Lee, AMS Worm Composting Coordinator

What is vermicomposting? Vermicomposting is the use of worms to break down organic waste into recycled nutrient sources for plants. It closes the energy loop in food production, reducing our food waste into a valuable product (vermicompost) that can then be used in gardens for food production.

Last summer, we bought a ‘Worm Wigwam’ bin, and set it up in the compost room of the SUB. It’s been in operation ever since with a starting amount of 10lbs (or roughly 10 000) red wiggler worms. These guys are ideal for vermicomposting food waste because they eat a lot! If you’re familiar with the SUB, you’ll know that this building produces a lot of food, and a lot of food waste too. During a Waste Audit of the SUB in 2009, it was found that ~40% of the waste that ends up going to Vancouver Landfill was food waste, perfectly compostable, organic matter – food for worms, and other decomposition organisms!! Why drive 30 km to Delta, and pay tipping fees to the City of Vancouver  to dispose of perfectly good food waste when we can feed it to worms in the SUB?

Main reasons for vermicomposting at the SUB:

  • Waste reduction – A large component of food is actually water. When food waste is composted, waste is reduced by a considerable amount (~60%)
  • Waste diversion – By separating out the food waste and sending it to the worm bin, a lot less waste ends up in the Vancouver Landfill
  • Reduced energy – On-site worm composting will reduce the requirement for transportation of waste (think of those rising fuel costs), and will reduce worker hours spent driving
  • Reduced Greenhouse Gases – The decomposition of organic (food) waste in landfills produces greenhouse gas (primarily methane) which contributes to climate change. Also, remember all those driving hours spent going back and forth to the Landfill?
  • Creates compost – Vermicompost is considered the best type of compost for improving soil quality which is important in growing healthier plants
  • Reduced fertilizers – By recycling nutrients from food waste, and improving soil quality through the production of vermicompost, dependence on chemical fertilizers will be significantly reduced. Keep in mind that fertilizer production requires the use of fossil fuels, and needs to be transported to the consumer. Vermicompost is more effective than fertilizer when it comes to nutrient retention in the soil, and there are numerous benefits to the soil/plant ecosystem when compost is used (none of which can be replicated by fertilizers).
  • Reduced costs overall – Vermicomposting is less expensive than other methods of waste management. This is arguable, and context-specific, but I crunched some numbers and found that vermicomposting at the SUB to be cost-comparative with the least expensive method of waste management available to UBC. Also remember that scale-up of the current worm bin project could lead to a significant increase in worm and compost production. This stuff is valuable (ask any farmer or gardener), and a cost-recovery, or even profit-making venture could be a future project for some lucky students!

 

LFS Orchard Garden Vermiculture Project | January Update

What is vermicomposting?

by Jay Baker-French

According to Dr. Peter Stovell, a retired UBC professor who has devoted many years of his retirement to developing worm composting, or vermicomposting, worms should be employed to enhance the overall composting process; they do not — and can not — entirely replace it. So, what is composting, and how can worms enhance it?

photo by Emme Lee

Composting is, broadly, a strategy to accelerate the natural process of decay that occurs when organic materials are discarded or die. It is like concentrating the upper few inches or centimeters of an active, healthy soil into a small space. The processes of decay are enhanced because of the decrease in surface area to volume ratio: there is increased thermal protection, decreased loss of water and, given sufficient carbon in the pile, gaseous nutrients (especially nitrogen), and because of physical agitation by compost managers, a more thorough decomposition throughout the mass. Of course, composting is considered beneficial in so far as it serves to harness these enhanced decay processes with an eye to improving the productivity of food producing soils, usually in agricultural or horticultural food systems.

Now, what about earthworms? In the soil, one of the functions earthworms serve is to make plant nutrients more available to plant roots. Earthworms “graze” the bacteria and fungi that do the primary work of decomposition. By digesting these microorganisms, the nutrients they contain are converted into simpler forms that are held in the soil carbon network, or humus. When worms are included in the composting process, they serve to further enhance the natural processes of decay, creating a finished compost product with superior nutrient availability and physical properties when applied to soils. In accord with the way earthworms feed in soils, they do their work in the latter part of the composting process, after the primary decomposers (bacteria and fungi) have gotten a start. They generally wait for the excessive heat of the thermophilic compost to dissipate, then move in to feast on the healthy populations of bacteria and fungi. Yum!

Worms require good aeration, so vermicomposting units must have good drainage. It is also important to include enough “bulking agent” – carbonaceous, spongy materials such as fall leaves, shredded cardboard, or untreated sawdust – mixed with the feedstock to lock in lots of air. However, worms also must have their bodies moist at all times, so the mixture fed to them must be moistened, like a damp sponge. Lots of air, lots of water. Our reactor will be a upward-feeding system, meaning that new feedstock/bulking agent mixture will be added on a regular basis from the top in an even layer. The uppermost, newest layers of feedstock will heat up because of the metabolism of the primary decomposers. We will cover this layer with a thick layer of leaves or other unmixed bulking agent in order to insulate the warmth inside the composting mass below. Meanwhile, the worms will be active in the older, less warm, deeper layers of feedstock. The warmth generated in the newer layers will keep the worms nice and  warm through the winter. We’ll also make sure windchill doesn’t kill our worms by insulating the whole bin. We hope to maintain happy worms all winter long, processing the food scraps from Agora Cafe. Then in the Spring we will “harvest” some very valuable soil amendment for next year’s crops. Here’s to worms!