How we make food waste go further

Ever wondered what happens with your leftover food on campus? Thanks to food waste innovations, your leftovers can actually be turned into energy! 

Tackling food waste is just one of the many ways we keep our campus sustainable through food, and thanks to a process called anaerobic digestion we can take it to the next level.

What is anaerobic digestion?

A natural process where microbes break down organic materials like food waste, without the use of oxygen – a very clever way of composting food while producing renewable energy and avoiding carbon emissions.

Think of it like a giant stomach that 'digests' waste and turns it into something useful, like: 

• Biogas, which can be used to generate electricity and heat, fuel vehicles, or be fed straight into the national gas grid. 
• Digestate, a nutrient-packed fertiliser that can be used on farms and gardens. 

How it all works:

1. Organic waste (like food leftovers) is collected and prepared. Any packaging is removed and the waste is blended. This is an important step as the mix has to be not too dry or too wet to keep the bacteria happy. 
2. The mixture is then pumped into a sealed, oxygen-free tank called a digester. 
3. Microorganisms (bacteria) get to work munching through the waste. As they digest it, they release biogas, the same stuff that powers gas cookers and boilers. 
4. The biogas floats to the top of the tank and is collected to use for fuel. The remaining solids and liquids (digestate), settle at the bottom and are later removed. This material is nutrient-rich and can be used as an organic fertiliser. 

Just from your food waste, we can burn the biogas it produces to produce electricity and heat, pump it into the gas grid to heat homes, and use it to fuel vehicles as a green alternative to petrol or diesel, pretty cool, right?

By turning waste into energy, we can cut down on landfill use – in turn reducing pollution – and create a system where waste becomes a resource. 

So next time you scrape your plate, remember that leftover lasagne might heat someone's home or power an electric bus one day!