What is organic waste?
When talking waste management, organic is a broad, generic term describing waste derived from any type of living matter.
A mighty oak, the family dog, and icky germs are all examples of living things. As they feed, grow, and die, living things create organic waste.
Organic waste is decomposed by other living organisms. These degradation catalysts can rely on physical decomposition (like earthworms and dung beetles) or chemical (like bacteria and fungi). Their preferred environment can be aerobic (with air) or anaerobic (without air).
Paper, cardboard, and pallets are all organic wastes because they’re manufactured from trees, cotton, kenaf or other fibrous plants. Egg shells, fish bones, and moldy cheese are organic waste because they came from animals. A discarded biodegradable bag is considered organic waste because it was made from a plant-based polymer that can be decomposed by bacteria. Potatoes and wheat are examples of plants that can be used to make these types of plastics.
“Biodegradable” is not necessarily compostable at all types of composting facilities. Some biodegradable materials don’t breakdown fast enough using slower composting processes and, like conventional plastics, can be considered contaminants. On the other hand, many high-rate processes will be able to handle both biodegradable and compostable plastics. Waste that has been certified “compostable” by the BPI or other certification agency can usually be accepted and managed by the widest range of composting facilities.
Given enough time, all organic matter will biodegrade. However, some ingredients or finishes can be toxic to feeding microbes. Therefore, most composting facilities, including high-rate operations, do not accept things like treated lumber, even though they may be derived from organic materials. Exceptions might be made for paints and treatments that have been tested to prove they will biodegrade within an acceptable timeframe.
Organic is not the same as “certified organic”
Within the organic waste management arena, the word organic is not to be confused with the commercial “certified organic” marketing label used by growers and manufacturers.
The 1990 congressional decision resulting in the designation of “organic” as restricted marketing lingo was probably not representative of that august body’s finest hour. The conscription of a term that had been used generally in chemistry and other common vocabulary for hundreds of years – and then attempting to give it a very narrow definition — has created quite a bit of consumer confusion in the ensuing decades.
But organic waste is not always as nature made it, either. Food and other biodegradable wastes can contain man-made additives. Fortunately, a modern, high-rate composting system is capable of degrading many synthesized chemical compounds as it breaks down organic material. Therefore, when the urban area is served by one of these advanced systems, the organic fraction of the municipal solid waste stream is, most likely, both biodegradable and compostable. Even some non-organic wastes, like (untreated) gypsum board, can be added to the compost blend to improve its market value.
Composted organic waste as a soil amendment
As a soil amendment, compost is always organic, but may not be “certified organic” – unless it has met certain criteria for certification. Most of the time, the word organic on a compost label simply means the soil amendment was made from organic (the generic use) material and is not a synthetic fertilizer/amendment product.
If “certified organic” compost is preferred, then the consumer needs to look for a product sporting a certification symbol from a legitimate, USDA-accredited certifier. But know that organic certification addresses ingredients and processing methods only, not product quality.
Quality standards for compost products are established under the U.S. Composting Council’s (USCC) Seal of Testing Assurance (STA) program. Compost manufacturers certifying products under the STA label focus on meeting requirements related to maturity, pH, salts and other quality indicators, all verified by regular product testing by USCC-approved laboratories.
Approved labs are required to use equipment and testing methods specific to compost products, which differ from the more commonly-used soil testing criteria.