Is centralized composting the only solution for diverting organic wastes from the landfill in our region? It certainly isn’t, but according to the 2005 RDCK study, it is the best one.
The study looked at a number of options including anaerobic digestion, waste to energy, biofuel production, vermiculture, lime stabilization, and of course large scale composting.
All available feedstocks (sources of organic wastes) in our area were included, including those that might come from the Castlegar pulpmill, waste treatment plants, hospitals, restaurants, grocery stores, agriculture, and private residences.
Lets take a quick look at the options they considered:
- Anaerobic digestion: Organic wastes are broken down in the absence of oxygen, usually in an enclosed container. Biogas (methane) is produced. A crude form of this occurs within landfills, and some landfills collect the resulting biogas for energy production.
- Waste to Energy: Basically, this is just burning the compost to produce heat which is used to produce energy. Waste to energy can also be used for many kinds of garbage – think “incinerator with a generator”.
- Biofuel production: Similar to anaerobic digestion, the production of biofuels from organic wastes involves a low oxygen process called pyrolysis, which can produce a range liquid and gaseous fuels. The city of Surrey is in the process of implementing this technology, which will be used for biosolids (from human waste treatment plants). These kind of wastes can cause issues with composting do to regulations regarding sale of the finished product.
- Vermiculture: Using worms to facilitate the breakdown of organic matter, creating worm castings and a “vermicompost” product valuable to gardeners.
- Lime Stabilization : The process of adding lime to raise the ph and make the organic material unfavorable to pathogens – sometimes used for biosolids from waste treatment plants.
- Composting: Decomposition of organic matter in the presence of air and moisture. Can be done in controlled vessels or using a number of open air or modified open air techniques.
The authors of the study determined that composting was the only technique worthy of further consideration since the above choices exhibited one or more of the following:
- Inability to handle the variety of waste streams available.
- Too expensive for the volume of material or value of end product.
- Limited local market for end products.
- Technology is still under development of has had limited commercial uptake.
The report suggested that the volumes of organic waste in the Nelson – Castlegar – Trail corridor could justify the development of a central composting facility. For more rural areas such as RDCK east, where there are less volumes produced, they said that transportation costs could make participation in the facility impractical. For such outlying areas, it suggested backyard composting could be a solution.