The term “Biodegradable” simply refers to the ability of substances to disintegrate (decompose) when acted upon by microorganisms such as fungi and bacteria with or without oxygen.
This decomposed material is then absorbed into the natural environment.
Anything biodegradable is animal-based, plant-based, or natural mineral-based. Their origin of the substance and the extent to which this substance has been processed determine the rate of degradation.
This process begets no ecological danger or harm, in fact, it mostly helps to cleanse the environment of excess waste products when these materials are reabsorbed and reused by the earth.
Nowadays, in addition to recyclable waste, industries, and factories have adopted the production of Biodegradable plastics and other materials to reduce the accumulation of dangerous waste products that are responsible for land, water, and air pollution.
However, many industrial materials, even those termed Biodegradable can decompose in a harmful way, releasing chemicals and other dangerous substances into the environment.
Some of these harmful Biodegradable materials are disposable cups, utensils, steel. When these products are decomposed on landfills, they release gases such as methane which is a potent greenhouse gas when released in the atmosphere.
It is required that this type of degradation is done in a controlled environment, where they can be monitored closely, the released gases collected safely.
These collected gases such as Methane are of great value when released properly.
What are Biodegradable Materials?
Biodegradable materials are those materials that are capable of being decomposed by bacteria or other natural organisms.
These materials can be broken down (decomposed) into methane, carbon dioxide, or other organic molecules by micro-organisms. They are widely referred to as “Bio-waste”.
Bio-wastes which are decomposed by microbes can as well be broken down by abiotic factors and elements such as temperature, oxygen, UV, and more.
Some examples of such wastes are food materials, kitchen wastes, and other natural wastes. Microorganisms and other abiotic factors together break down these complex substances into a simpler organic and inorganic matter which eventually suspend and fade into the soil or are collected for other purposes( e.g. Methane).
The whole process is natural which can be rapid or slow. Therefore, the environmental issues and risks caused by biodegradable wastes are low.
Although, excessive decomposition of these organic and inorganic matters on the same area, within a close range of time, can be life-threatening sooner or later. For this to be avoided, composting should be practiced.
In composting, the bio-wastes are disposed of in a pit and covered over time. When they are acted on by microbes and abiotic factors, they are decomposed and used as manure for cultivation and other industrial uses.
Bio-wastes are commonly found in municipal solid waste as green waste, paper waste, food waste, and biodegradable plastics. Other biodegradable wastes include human waste, manure, sewage, slaughterhouse waste, and the rest of them.
What Materials are Biodegradable?
Plastic: Biodegradable plastics have become a popular replacement for non-biodegradable plastics due to the high consumer demand for green alternatives.
Rather than remaining as it is for many years, they are acted on by microbes and turned into biomass, carbon dioxide, and water.
In the absence of oxygen, they are turned into methane instead of carbon dioxide.
Some examples of these Biodegradable plastics include;
- Cellulose-based plastics
- Soy-based plastics
- Bacteria based plastics
- Lignin based plastics
- Starch-based plastics
- Natural fibers reinforcement plastics
Compost: These materials usually decompose faster and often leave no distinguishable, visible, or toxic residue. These materials create “humus” which is rich in nutrients and very suitable for plant growth.
Example of compost materials are;
- Food substances,
- Animal and human dung,
- Sewage, etc.
Fiber: These are fabrics that break down quite naturally and easily by the effects of microorganisms. The extent to which these fibers decoalmpose is highly dependent on the number of chemicals used in the life cycle of these textiles. The more the chemicals, the longer it takes for the fabric to disintegrate which can ultimately cause environmental damage.
Some examples include;
- Organic Cotton
- Organic Bamboo
Cork: They are light brown materials gotten from the outer part of the bark of cork oak. They are 100% biodegradable and renewable. Decomposition is faster when they are in pieces.
Pulp: These are prepared by mechanically and chemically separating cellulose Fiber from fiber crops, wood, waste paper. When they are mixed with water and other chemicals, they can be used to produce paper and paper products. These materials decomposed over time mostly due to their storage condition, the presence of moisture, and acid from the environment or from within the pulp.
Straw: This is a byproduct composed of dry stalks of cereals after the removal of chaff and grain. When this straw mixes with the soil, it is quickly attacked by fungi and bacteria. These microorganisms feed on the carbon and energy from the straw, gradually decreasing the mass of the straw till it’s completely decomposed.
Bio-based Polymers: These are alternatives to petroleum-based plastics. Biological materials such as starch and fiber are incorporated into these polymers. The physical and chemical characteristics of this material undergo deterioration and degrade entirely when exposed to microbes, aerobic and anaerobic processes.
Economic importance of Biodegradation
- It harnesses the forces of nature with which waste is reduced, and the earth made less toxic.
- With biodegradation, organic wastes are converted to valuable resources.
- The process of biodegradation serves as a source of food for microorganisms (bacteria, fungi, algae).
- Biodegradation decomposes materials that are in turn absolved into the soil, enriching the soil with nutrients crucial for plant growth.
- Some biodegradable materials are entirely toxic and harmful to both plants and animals.
- When materials, such as carcasses decompose, they release an unpleasant odor when not decomposed properly.
In conclusion, “biodegradable” is the term used to represents materials that undergo nature’s recycling processes to create, for the most part, a better functioning living system.