Recycling 101: All About Compost

The Whys, Hows, and What Ifs of Food Waste Disposal

We’ve spent a lot of time in this series talking about recycling, especially when it comes to plastic, glass, and other materials. One area we haven’t discussed as much is food waste. Food waste is a huge problem across the world that accounts for roughly 6% of methane emissions yearly. That’s 1.3 billion tonnes of waste globally.

Reducing food waste is the most important thing we can do – that means buying less than you need and planning out meals. It also means calling on companies to produce less, so less goes uneaten. However, when that fails, we are left with a big, stinking pile of food waste.

So what can we do? Compost it!

What is Compost?

Compost is an earthy, soil-like material made up of decayed organic matter including food scraps, garden waste, and paper products. Sometimes called “black gold,” compost is made by breaking down organic materials slowly over time. This can happen in a controlled environment such as a composting site or naturally, like when fallen autumn leaves break down and return to the soil in the forest.

While all organic material will break down naturally, composting in a controlled environment helps speed up the process by providing an ecosystem with bacteria, worms, and aeration. The end result is a compost which can be used to regenerate soil and provide nutrients back into the ground.

Why Compost?

Composting is a great way to reduce food waste at home, at work, or in the community. It’s a way to recycle organic matter back into the ground. There are many benefits to composting, which we break down below.

Benefits of Composting

Reduces Soil Erosion

Soil erosion is when the top layers of soil are worn down, which leads to less fertile land and puts areas at higher risk of flooding and landslides due to loose soil. Compost helps reduce this because it is great at binding soil together, especially when infiltrated with water. Due to the main three nutrients in compost – nitrogen, phosphorus, and potassium – compost can hold up to 20x its weight in water, which makes it great for retaining rain and increasing soil resiliency, especially in drier climates. This in turn can help mitigate soil erosion that happens when rainfall washes important nutrients away.

Helps with Carbon Sequestration

As soil degrades over time, it releases carbon into the atmosphere. Compost regenerates the soil and helps it retain and even pull carbon out from the air. As such, compost is a great carbon sink. According to the Massachusetts Institute of Technology, soil has the potential to sequester nearly one billion metric tons of carbon dioxide from the atmosphere each year.

Reduces Landfill Waste

When food scraps are separated from landfill waste to be composted, this helps divert more from landfills. If food scraps and associated organic waste go to landfills, they rot anaerobically (without oxyen), which releases methane – a very potent greenhouse gas that contributes to climate change. Additionally, landfills need land to house waste, so by diverting organic material, we are helping prevent overfilling the landfills.

Acts as a Natural Fertiliser

Compost is a nutrient-rich material that acts as a natural fertiliser that helps plants grow in gardens, farms, and forests. Since the decomposed food is filled with good nutrients, these are then reabsorbed into the soil to aid plant growth. It keeps the soil arable and healthy, which means healthier crop yields without as much of a need for harsh fertilisers that damage the soil in the process.

Types of Compost

When most people think of composting, they think of traditional composting (which we’ll dive into below) is when you use nitrogen-rich green material like food scraps and mix it with carbon-rich brown material like dead leave, cardboard, or sawdust. However it is not the only way to produce compost and may not be the best in all circumstances.

Hot Compost

Hot composting is the most traditional method of composting. In its simplest form it’s when you control the environment and use aeration to quickly break down organic matter. When conditions are right, oxygen helps microorganisms heat up the material, which quickens the breakdown process.

In hot composting, temperatures of a compost pile top 71°C, but will need to be at least 46°C in order to properly break down. Hot composting requires a more hands on approach. This means ensuring that carbon browns and nitrogen greens are balanced (usually a 3:1 ratio) and that the pile is properly aerated.

Hot compost takes around 4-6 weeks to break down and is often the best way as there is no smell and the heat kills all weeds and pathogens. However, it’s often hard to get right and takes a lot more work.

Cold Compost

Cold Composting starts with the same basic principles of hot composting – taking greens and browns and throwing them into a pile together. However, unlike hot composting, cold composting is a much more hands off approach. Instead of aerating, you let the compost break down without oxygen, which is a much slower process.

Cold composting is usually more smelly and takes considerable time to break down. It can be done with less materials than hot composting and requires less maintenance. However, this method should only be done away from homes and gardens as rotting materials may attract vermin. Overall, cold composting can take six or more months to fully decompose.

Vermicompost

Vermicomposting is the process of using worms (generally red worms) to break down organic matter over a series of months. Generally, the process takes 3 to 4 months to break down the materials into usable compost. Unlike other composting methods, you don’t need to worry aerating the material and it can be done anywhere – indoors or outdoors.

Vermicompost is a great option for smaller spaces, including indoor spaces, and takes less time than cold composting. It also results in more nutrient-rich compost, but can be more costly to set up and also may not kill all pathogens like hot composting does.

Bokashi Compost

Bokashi composting is a type of anaerobic composting that involves fermenting organic materials in a sealed container. It’s technically not a full composting process as the end result isn’t nutrient-rich compost, but fermented material that can then be buried in the earth to complete the composting process.

To ferment organic material using the bokashi method, you only need food scraps (no carbon-rich browns required), an airtight container, and microbes, which you can generally buy from home improvement stores.

Bokashi is mostly used for small space composting or when composting needs to be done quickly. As the fastest method, bokashi compost will be ready to be buried within 10-14 days. It’s great for people that want to compost but live in small spaces without the area to do traditional composting or even vermicomposting.

Where to Compost

Composting has become more and more prevalent as people, organisations, and communities look for new ways to address the climate crisis. Composting, while not the most impactful, can make a difference.

There are many places you can compost. If you want to get started at home and have a garden or outdoor space, you can set up your own DIY home composting bin or buy a tumbler from a local outdoors store. Additionally if you don’t have much room, you can try vermicomposting or use the bokashi method.

If neither of those suit you, you can look for local composting centres to take your food and garden scraps. While some governments have started rolling out composting as part of the normal council waste pickup, these aren’t yet widespread. However, many community gardens, farms, and non-profits do offer composting facilities for individuals and businesses. Do some research to see if they exist in your community.

Finally, composting does exist on an industrial scale as well. Many private waste providers can accept organic material as part of their waste collection. Some of these are even able to accept compostable plastics which aren’t able to be composted in home or community composting. It’s important to double check though before assuming.

There are always ways to divert your personal and community food waste, all of which are preferable to sending them to the landfill.

The Wrap Up

Food waste is prevalent throughout our lives. From the food waste in the grocery stores to the leftovers we forget about in the back of our fridge, it’s an avoidable part of waste management. Composting waste has so many benefits for the earth and it’s easy to get started.

Whether you compost at home, in the community, or through a waste provider, you’re preventing unnecessary waste from landfill and creating a regenerative material in the process.