Transforming food waste into bioenergy
15 July 2021
Food waste is one of the many environmental problems caused by modern agriculture. Biotechnology innovations may help us tackle it by turning waste into energy.
For decades now, bioenergy has been posited as a renewable and clean source of energy. Biomass, particularly from forestry, is the largest source of renewable energy in the UK. However, recent research suggests that forestry bioenergy isn’t always carbon neutral. Trees and plants are renewable, but burning them releases large amounts of carbon in the atmosphere at once, and growing equivalent forests takes decades, if not years.
Therefore, to produce truly clean bioenergy, a more sustainable alternative is to use food and agriculture waste.
The food and agriculture sectors have a massive environmental footprint. It starts with the massive amounts of land and water required and the use of synthetic agrochemicals, as well as things as seemingly innocuous as methane-emitting cows. Food waste along the long supply chains contributes to further emissions. While developed countries have lower supply chain losses as compared to the developing ones, they also produce a greater amount of waste within households. Just when you think things couldn’t get any more environmentally unfriendly, as food waste decomposes in landfills it releases methane and pushes toxic metals and pathogens into the surrounding environment.
Several companies have identified food waste as a potential source of bioenergy. This helps the environment in two ways. Firstly, it takes food waste away from landfills. Secondly, it offers clean energy, reducing our dependence on fossil fuels.
Digesting food waste to produce energy
Anaerobic digesters are airtight containers that produce methane from food waste in a process that’s very similar to what happens when food waste is dumped in landfills. The four-step process is driven by a community of bacteria that thrive in the absence of oxygen and break down the organic matter into simpler molecules, including methane.
ReFood is a British food waste recycler that uses anaerobic digestion to produce biomethane for the UK’s National Grid. Over a month-long process, bacteria convert the blended organic matter into methane.
“All food waste streams are suitable for the ReFood process – from fruit and vegetables to meat, fish, bread, cakes, biscuits, pasta, and more,” said Philip Simpson, Commercial Director at ReFood. “We collect plate scrapings, bones, fat, gristle, out-of-date produce, processing residues, and waste beverages. Thanks to our state-of-the-art depackaging equipment, we even welcome food still in its original packaging – a hugely valuable service, especially for grocery retailers.”
Amur is another British company working in this area. In addition to running its own facilities, the firm also provides a rapid analysis of the food waste going into the process to its customers, in order to quantify the energy-producing potential for all kinds of food waste.
“All feedstocks received by the site undergo strict analysis to ensure that firstly, they are suitable for feeding and are not contaminated in any way, and secondly that the material gives good biogas yield. The material is then blended, based on its nutritional profile, into the overall feed mixture to achieve the target carbon to nitrogen ratio,” Christine Parry, Head of Development and Innovation for Amur, told me.
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