This blog is intended to provide a simple, easy to understand overview of biodegradation for everyone. Whether it is your first time learning about biodegradation, or you are just looking to refresh your understanding of the topic, we hope this advances your knowledge of biodegradation.
Definition of Biodegradation
You may come across many different definitions for biodegradability on the web, but put simply, it is the breakdown or decomposition of materials by microorganisms. Specifically, biodegradation is the process where microorganisms break down complex materials into forms that can be used by living systems. Bacteria and Fungi are typical examples of microorganisms that are involved in the biodegradation process. Depending on the material that is being broken down and the environmental conditions, the degradation time can vary drastically from days to decades.
Types of Biodegradation
Biodegradation can generally be broken down into two main types: Anaerobic and Aerobic.
Anaerobic biodegradation is when the biodegradation process occurs in the absence of oxygen. The result of anaerobic biodegradation is biogas, which consists largely of methane along with smaller amounts of carbon dioxide and hydrogen. Since biogas contains methane, which is harmful to our atmosphere, it is often collected and used for eco-friendly power generation.
Aerobic biodegradation takes place in the presence of oxygen. Unlike anaerobic biodegradation which can release potentially harmful methane into the atmosphere, the result of aerobic biodegradation is mainly carbon dioxide. Since the infrastructure needed to manage aerobic biodegradation is much simpler, this method is usually preferred over anaerobic biodegradation.
Types of Environmental Conditions
There are many different environments where your products may eventually end up. Each different location has a unique set of environmental conditions that can affect how a material degrades. With this being said, there are a few overarching conditions that are commonly examined: Industrial Compost, Home Compost, Soil, Freshwater, and Marine environments.
Industrial composting is an established process for transforming biodegradable waste of biological origin into stable, sanitized products. The compost conditions usually range from 50-70 degrees Celsius and moisture levels are normally kept within 40%-60% for a minimum of 21 active days. The degradation rate of industrial composting is generally faster than other conditions.
European Bioplastics gives an overview of industrial compost conditions.
Home composting generally relies on atmospheric temperatures and can occur in one of two ways: Backyard composting with a pile, or Vermicomposting (worm composting). If organized extremely well, the compost temperature conditions can still reach up to 70 degrees Celsius. The degradation rate of home composting is still relatively slower than industrial composting.
While there are no regulations around home composting, the EPA does provide guidelines and suggestions.
Biodegradation in soil occurs in an open environment, such as the ground outside your home. The temperature and humidity will be relatively the same as the atmospheric conditions around the soil. This process occurs slower relative to home composting and industrial composting.
While it is unfortunate, many products may end up in a freshwater or marine environment at the end of their useful lives, making freshwater and marine biodegradability very important. Taking into account all the biomes in the world, the average freshwater environmental temperature is roughly 10-12 degrees Celsius. This process occurs slower relative to biodegradation in soil.
Biodegradation in a marine environment, such as the sea or the ocean, occurs at atmospheric temperatures. Due to the marine conditions, the bacteria are also diluted. This results in marine biodegradation generally being the slowest environment for biodegradation.
Overall, biodegradation is an important step in a circular economy. As its core, it involves microorganisms, such as bacteria or fungi, breaking down materials into usable, less complex compounds. This can happen either anaerobically (in the absence of oxygen) or aerobically (in the presence of oxygen). When it comes to aerobic biodegradation, this can take place across a wide range of environmental conditions, each of which has a unique effect on the biodegradation process.