Biodegradable and decomposable are two words that we use interchangeably when discussing recycling.
Climate change effects continue to threaten our planet.
To reduce the effects, people worldwide continue to become conscious about the environment.
And one way to do that is switching to biodegradable and compostable products.
But can biodegradable waste be decomposed? Yes. Biodegradable waste gets broken down into simpler units that decompose by microorganisms to form humus.
Would you like to know how that happens? Please keep reading till the end!
What is Biodegradable Waste?
You must have seen some products labeled as “biodegradable.” Or you’ve probably heard several times that wastes from food, lawn, garden, vegetable, etc., are biodegradable waste.
But what exactly is biodegradable waste? Biodegradable waste is any substance that quickly breaks down into simpler units when exposed to UV radiation, water, oxygen, and micro-organisms.
The microorganisms involved may exist in the waste or the soil.
So they act on the waste, changing them into decomposed material which increases soil fertility.
For a waste to be biodegradable, it must be natural mineral-based, animal-based, plant-based, or material.
Such waste will break down safely and quickly into very harmless compounds.
However, the breakdown rate of a biodegradable waste will vary depending on the original material it’s coming from.
The ASTM (American Society for Testing and Materials) defines biodegradable wastes as any substances that undergo degradation by the action of microbes such as algae, bacteria, and fungi that exist naturally.
Examples of Biodegradable Waste
Biodegradable waste may take any form, depending on its sources.
It can come from organic plants, animal materials, or natural minerals. Examples of such waste include:
- Food waste
- Paper waste
- Human waste
- Manure waste
- Sewage sludge
- Dead plants and animals
- Slaughterhouse waste, etc.
What is Decomposable Waste?
A decomposable waste can break down into simpler natural elements in a compost condition.
That’s why they are often called compostable waste.
Since the waste easily degrades into natural compounds, it doesn’t affect the environment.
ASTM defines decomposable waste as anything that can get broken down through biological processes (decomposition) to form water, carbon dioxide, biomass, and inorganic compounds.
The process leaves no toxic, visible, or distinguishable residue.
Under favorable conditions, the decomposition of waste may take around 90 days.
However, the time may vary from one type of waste to another.
Can Biodegradable Waste Be Decomposed?
The simplest answer is yes. Biodegradable waste can break down and decompose in the environment.
For that to happen, micro-organisms like fungus, bacteria, and algae must act upon the biodegradable waste.
In simpler words, biodegradable waste can undergo decomposition.
Decomposition is a biological process that occurs when fungi, bacteria, and other microorganisms feed on biodegradable materials.
The biodegradable waste gets buried or disposed into a pit to facilitate decomposition. Sunlight and temperature may also play a vital role in stimulating the decomposition of biodegradable waste.
While all decomposable waste is biodegradable, not all biodegradable waste is decomposable.
Biodegradable substances can degrade to form simpler molecules that may return to nature.
The simple molecules formed may also disappear totally into the environment.
However, the waste may sometimes leave metal residues.
With decomposable waste, they break down to form valuable humus rich in nutrients.
That’s why soils with decomposable materials are always very fertile for arable farming.
How does Biodegradable Waste Decompose?
We often dispose of biodegradable waste in landfills or a pit.
So how does organic waste decompose? The waste gets broken down into smaller units by decay or decomposition.
Microorganisms like earthworms, algae, fungi, and bacteria facilitate the decay of biodegradable waste.
Bacteria and fungi are saprophytic because of how they biodegrade organic matter.
Saprophytic nutrition involves:
- Fungi and bacteria cells secrete enzymes in the dead organic matter or soil to act on biodegradables.
- The enzymes consume the organic material, a process called extracellular digestion. That’s because digestion takes place outside the cells.
- Digested products get absorbed by bacteria or fungi.
Most biodegradable wastes decompose to form humus which is rich in nutrients that plants
can absorb.
What Factors Affect Decomposition Of Biodegradable Waste?
Various factors may affect the decomposition rate of biodegradables. They include:
Availability of Temperature
Decomposition of biodegradable materials is faster when temperatures are warmer. Low temperatures decrease the decomposition speed and time.
Moisture Level
There must be enough moisture for biodegradables to decompose faster. The vice versa is true.
Oxygen Availability
Decomposers need sufficient oxygen to break down the biodegradable waste during aerobic respiration. The decomposition rate reduces under limited oxygen as the microbes won’t be active under anaerobic respiration.
Availability of Microbes
Micro-organisms like fungi, bacteria, algae, earthworms, etc., must be available in plenty for the waste to decompose faster.
How Long Does Biodegradable Waste Take To Get Decomposed?
The decomposition of biodegradable waste varies from one form of waste to another.
Biodegradable waste can take several days, months, or even years to decompose, depending on the conditions available.
Examples of Biodegradable Wastes and How Long They Take To Decompose
Food Waste
Food waste is the second most component in American landfills. The decomposition time for food waste depends on the food type creating the waste.
For example, banana peels decompose in 2-10 days. Apple core will take about 2 months to decay. With orange peels, the decomposition takes up to 6 months.
Paper Waste
Paper is the largest solid waste collected by American municipalities. Under normal conditions, paper waste takes about 2-6 weeks to decompose entirely in landfills. But depending on the moisture availability in landfills, paper waste can take decades to decompose.
Bioplastics
Biodegradable plastics take 3-6 months to decompose entirely. The time may vary depending on the temperature and moisture level available. With synthetic plastics, they’ll take forever to decompose.
Other Biodegradable Wastes
- Cotton rugs: 1-5 months
- Rope: 3-14 months
- Wool socks: 1-5 years
- Paper milk cartons coated with plastic: 5 years
- Cigarette butts: 1-12 years
- Leather shoes: 25-40 years
- Rubber boot shoes: 50-80 years
Conclusion
Can biodegradable waste be decomposed? Yes. Biodegradable waste can easily degrade into simpler compounds that are decomposable through natural and biological processes.
Such waste is easy-going for micro-organisms like bacteria and fungi.
These microbes can digest the biodegradable waste, making it decay.
Humus is the resulting product that nourishes the soils.
However, the decomposition rate varies depending on the availability of oxygen, moisture, microbes, and temperature.
