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The Science Behind Our Eco-Friendly Gifts: What Does 'Compostable' Mean?
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The Science Behind Our Eco-Friendly Gifts: What Does 'Compostable' Mean?

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A solution often talked about to deal with mass single use plastic pollution, is to use compostable alternatives.

Items such as compostable cups and cutlery amongst others are often praised for their characteristics, and the fact that they are free of conventional plastic.

But what are the pitfalls of compostable materials?

There are a few important issues which aren't always advertised, and we will go through them in this blog. 

What Is The Definition Of 'Compostable'?

If a material is compostable, it can:

"Biodegrade in a set time frame, under set conditions, to form compost".

We've put this definition at the start to provide an absolute answer, and to avoid wasting anyone's time. 

The reason compostable alternatives to single use plastic have seen a peak in popular interest stems from the plastic pollution crisis.

Plastic pollution is a result of mass failure to dispose of plastic correctly. This means plastic ends up in the natural environment, where it harms wildlife.

Particular well known consequences of the crisis include the impact on marine wildlife. Marine animals such as Seabirds and Turtles are victims of plastic debris entering our seas and oceans. 

Because of the ever decreasing popularity of plastic, once hailed as the miracle material to change our world for the better, solutions are being developed to provide different options for consumers. 

One of these options is to create materials and items that are compostable. To understand why compostability is of interest to producers standing up to the plastic pollution crisis, we must first look at biodegradability.

What Does 'Biodegradable' Mean?

If a material is biodegradable, it can:

"Break down to form CO2, biomass and water, with the aid of microorganisms".

The easiest example of a biodegradable material is food. An apple core, in the correct environment, will break down to form CO2, biomass and water, with the necessary microorganisms present within a month.

Having the ability to biodegrade has the building blocks of the characteristics needed to fight plastic pollution.

Imagine if all plastic could biodegrade in any environment, in a short space of time. There would be no plastic residing, unwanted in the natural environment. There would be no plastic pollution.

At a first glance, being biodegradable is great. But as ever, there are problems with biodegradability, which we will come back to shortly.

As well as food, there are now manufactured items and materials which are biodegradable. Take PLA cups for example. PLA (Polylactic Acid) is a bioplastic, which has the potential to biodegrade as well as being produced from biomass (usually cornstarch). 

But a material's ability to biodegrade depends just as much as the environment that the material is in, as the chemical structure itself.

In landfill, waste is so tightly and densely packed in, that very few microorganisms, as well as oxygen, are present. This means that in landfill, a PLA cup will be unlikely to biodegrade, as the necessary microorganisms to aid the biodegradation aren't present. 

As well as in landfill, PLA might not break down in the ocean, or in say, a field in any reasonable time frame.

This is not saying the PLA cup won't biodegrade, but saying that it won't biodegrade within a reasonable time frame.

A key part of plastic pollution that makes it such a problem, is that plastic is built to last. For potentially hundreds of years, plastic could be present in the natural environment.

What good is a biodegradable material if it takes hundreds of years to biodegrade also? It could still cause harm to wildlife during this huge time frame, which arguably doesn't make it much better than conventional plastic. 

For a material to be able to stand up to plastic pollution, it must have an easy, accessible method of disposal that results in zero waste going to landfill or ending up in the natural environment. This is where composting comes in.

Why Is Composting Important?

Thinking back to the definition; compostable materials must biodegrade within a set time frame. This is what will make the difference in properly disposing of plastic. 

There are two types of composting: Industrial and Home. Below, we've made an infographic compiling the key points of both systems. 

home composting vs industrial composting

Home composting consists of your standard compost bin in the back garden. Most of the content is is food waste, and garden clippings.

Temperatures aren't particularly high, and average at around 20-30 degrees celsius. PLA cups that are put into a home compost bin are unlikely to break down within a reasonable time frame, as the conditions needed aren't present.

Where they are present, is in industrial composting plants. In these facilities, temperatures are much higher consistently. At least 58 degrees celsius is required to break down PLA cups within 6 months

We have developed a free post back scheme, that enables every compostable item in any of our gift sets to be fully composted.

LFHP Zero guarantees full compostation, and it means that zero waste will go to landfill. We have partnered up with an industrial composting facility, to ensure they can fully compost any of our used compostable items.

As a business, we place sustainability at the top of our priorities, and we love being able to guarantee zero waste going to landfill. 

Why Is There A High Demand For Compostable Alternatives To Single Use Plastic?

As images and videos from around the world are showing the damage that plastic pollution is causing, there is slowly but steadily a shift in thoughts about plastic.

Rightly so!

Plastic in the marine environment can result in severe injuries, or death, for marine animals. Floating plastic debris is mistaken for food by animals, including the many seabirds that hunt in our oceans. Until recently, no one was sure why this was. 

It turns out that floating plastic debris smells like food to marine predators. This is because of dimethyl sulfide, or DMS. DMS is released when krill ingest algae, a process that is constantly happening on a huge scale.

Marine predators have learned that this smell means krill will be present in the area, and they are correct.

Unfortunately, floating plastic debris makes a perfect environment for algae to thrive. This means that marine predators are inadvertently hunting what they believe to be krill, but it's actually plastic. 

Once ingested by the animal, it can be lethal. Death by suffocation, internal bleeding and starvation are becoming increasingly common, worryingly so. A Turtle has a 22% chance of dying from interacting with one piece of plastic debris. When Turtles encounter 14 pieces of plastic, the percentage rises to 50%. 

A less well known consequence of mass fossil based plastic production, is the contribution to the climate crisis. The processes required to extract, produce and transport plastic are extremely carbon intensive.

This extensive release of carbon emissions is constantly adding to the greenhouse gas density on global scale. By 2050, the greenhouse gas emissions from the plastic lifecycle could reach up 13 percent of the entire carbon budget. 

Are All Fossil Based Plastics Non Biodegradable?

No, there are some fossil based plastics which can biodegrade. The chart below shows the four different segments of plastics, divided by their biodegradability and source material.

different types of plastic chart

Conventional plastic is fossil based and non biodegradable. Common plastics in this group included Polyethylene, Polypropylene and Polyethylene Terephthalate.

As they are produced from fossil fuels, they have an extremely high carbon footprint. Because they can't biodegrade, they potentially could be present in the natural environment for hundreds of years. 

Because plastics such as PET can't biodegrade, they just break down into smaller and smaller pieces of plastic.

The second group produced from fossil fuels consist of plastics than can biodegrade.

Plastics such as PBAT and PCL sit in this category. Not being able to biodegrade as a result of the plastic being fossil based is a common misconception.

If we think back to the definition of 'biodegradable', it just means that the material can break down into carbon dioxide, water and biomass with the aid of microorganisms.

Plastics such as PBAT fulfill this criteria, making them biodegradable. 

What Are Bioplastics?

Bioplastics are materials with similar characteristics to conventional plastic, but they are either made from biomass, they can biodegrade, or both.

The category just mentioned, fossil based biodegradable plastics, are classed as bioplastics

The two other groups of bioplastics are produced from biomass.

The group in the top left of the graph consists of biobased non biodegradable bioplastics. Biobased Polyethylene and Biobased Polyethylene Terepthalate fall under this branch of bioplastics.

They have comparatively lower carbon footprints to fossil based plastics, as the plants used to produce the biomass actively take in CO2 when they are growing. The carbon is then only released when the bioplastic item degrades. 

Our favourite group of bioplastics include Polylactic Acid, the same material used to make the compostable cups mentioned earlier.

We love this group because they are produced from renewable resources, and can potentially be composted with zero waste going to landfill. This gives room for a true closed loop organic recycling system. 

In Conclusion

Hopefully throughout this blog, we've given a full answer as to what a material being compostable means. As well as giving the definition, we've delved deeper to discuss current misconceptions about composting, and also with biodegradability.

Gifts For Environmentalists

We wanted to create a shop that values sustainability, just as much as the joy each of our gifts for environmentalists brings to the recipient.

Our unique collection of gifts for environmentalists has minimal impact on the world around us, and is designed specifically to reduce plastic waste entering landfill. 

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