We delve into the impact of compostable plastics on the planet, here are some facts and myths about it
It’s evident that planet Earth and its inhabitants are quite aware of the impact of plastic on the environment. Traditional plastics or conventional plastics are not biodegradable, meaning they won’t break down easily in natural environments or even through biological processes. The end result? Plastic pollution, which has devastated Earth’s oceans and marine life. According to reports, around 75 to 199 million tons of plastic waste in our oceans currently, leading to the death of 1 million marine animals alone.
However, not all plastics are non-biodegradable. One subset of biodegradable plastics known to mankind is called ‘Compostable Plastic. Unlike traditional plastics, compostable plastics are designed to break down under controlled environmental conditions into water, biomass, and gases like carbon dioxide and methane.
Recent studies have shown that compostable plastics, which have had an increased demand, have the potential to actually play a key role in reducing waste. According to Statista, biodegradable plastic packaging is a growing market, with the global market value of biodegradable plastic packaging standing at nearly USD 2.8 billion in 2020. It is now projected to rise to approximately USD 9 billion by 2026. Additionally, compostable plastics are often made from bio-based sources like sugar beets, seaweed, or other plants, with the materials even offering environmental benefits. However, before we delve into the impact of compostable plastics on the planet, here are some facts and myths about it:
THE FACTS
Compostable Plastics Are Designed To Biodegrade
Compostable plastics are a subset of biodegradable plastics that are designed to break down under controlled environmental conditions into water, biomass, and gases such as carbon dioxide and methane. Environmental conditions affecting compostability include temperature, moisture level, pH, oxygen, and the microorganisms present. Duration of exposure under these conditions is a significant factor also. Although compostable plastics are biodegradable, not all biodegradable plastics are compostable. EU regulatory definitions for biodegradable materials exist (Dir2019/904), however, the term ‘biodegradable’ is often misused and applied to a broad range of materials. Environments such as soil, and fresh or marine water are uncontrolled, and therefore the timeframe for a material to biodegrade in them varies greatly. Without a specified environment or timeframe, the term ‘biodegradable’ can be misleading and is not an assurance that the material will biodegrade within a reasonable timeframe.
Not All Compostable Plastics Are Home Compostable
There are many differences in the methodologies of composting when talking about biodegradable plastics. While compostable plastics are designed to be compostable, not all of them are home compostable. Compostable plastics are designed to be either industrially compostable or home compostable. Industrial composting processes are the most optimal: with controlled temperatures of ~55–70℃, moisture, and oxygen levels. Home composting practices vary widely and therefore present more challenging conditions: with a wide range of cooler temperatures of ~20-60℃ and variable moisture and oxygen levels. Compostable plastics designed to break down under industrial composting conditions may not break down under home composting conditions.
They Provide Environmental Benefits
As discussed earlier, compostable plastics do carry tremendous potential as they provide the following benefits;
i. Reduces greenhouse gas emissions from organics
ii. Made from plant-based, renewable materials
iii. Reduces dependency on fossil fuels
iv. Can be recycled into nutrient-rich compost
THE MYTHS
Compostable Plastics Biodegrade In Landfills
Unlike the myth that compostable plastics have the capability of bio-degradation in landfills, it could not be further from the truth. The absence of oxygen in a landfill means that waste biodegrades at a very slow pace in it. As it stands, industrial composting is the best probable biodegrading option for certified compostable bio-plastics like PLA.
Home Compostable Plastics Is Equally As Harmful As Traditional Plastics
Unlike traditional plastics, compostable plastics are not dependent on the depletion of fossil sources. Home compostable plastics are made up of abundant and renewable sources like sugar beet, cassava, corn, and sugarcane. All these are expected to reduce the environmental impact in the future. Plant-based materials are not only compostable, they are renewable. Bagasse, for example, is a material made from sugarcane pulp – a byproduct of the sugarcane industry. Rather than being burnt, this material can be recovered and have a useful life in our food service industry before being recovered, composted, and returned to the soil to provide nutrients for – wait for it – more plants.
- Compost is beneficial to soils, plant, and animal life in many ways:
It enhances soil structure and quality which promotes plant growth and water retention. - Composting sequesters carbon and promotes an abundance of beneficial microorganisms which makes our soil fertile and productive.
- It reduces the reliance on chemical fertilisers, minimising the impact of contaminated water run-off in our rivers and marine environments.
Compostable Plastics Can Be Littered In Oceans
While compostable plastics are biodegradable, they should not be littered in the oceans. The reason behind that is that when compostable plastics end up going into the oceans or other natural ecosystems, they may not have access to the desired composting conditions. This means that they too, could lead to plastic pollution.
