Growing Food on a Landfill: Wiltshire Super Midden Plans to Turn Waste into Fresh Produce

Growing food on a landfill could soon become a reality at the Wiltshire Super Midden, where cleaned carbon dioxide and heat from waste will grow crops.

In Wiltshire, England, a waste company plans to grow food in greenhouses sitting on top of a landfill. The project would use “cleaned” carbon dioxide (CO² ), captured from rotting waste, to grow crops like avocados. If approved, this would be the first project of its kind in the world.

Crapper & Sons Ltd, the company behind the plan, already captures methane from its landfill to generate power. Now, it’s proposing to use the heat and CO² created from that process to boost plant growth in on-site greenhouses. The effort aims to supply up to 80% of the fruit and vegetable needs for nearby towns, including Royal Wootton Bassett, Malmesbury, and Brinkworth.

Landfills release gases when organic waste (like food scraps) breaks down. Crapper & Sons captures this gas—mostly methane—to generate electricity. In the process, CO² is also produced. While most landfills let this CO² escape into the air, this project would reuse it in a new way.

The cleaned CO², free of harmful chemicals like hydrogen sulfide, would be pumped into greenhouses built above the landfill. The high CO² levels would help plants grow faster and stronger. This process is already used in some European greenhouses.

Nick Ash, the project director, said, “What comes out of the top of the gas engine is quite clean CO². In Europe, that’s already used in greenhouses so that we would get that into our greenhouses.”

The greenhouses won’t have any contact with the landfill soil. Instead, they’ll use hydroponic systems—plants grown in nutrient-rich water. This keeps the crops safe and clean. The idea is to make food grown on landfills not only possible, but also sustainable and healthy.

Because greenhouses can operate year-round, the project could provide a steady supply of local produce. That means fewer imports, lower transport emissions, and fresher food.

The team plans to grow foods that are not commonly produced in the UK, such as avocados. Since the greenhouses will be heated by waste energy and enriched with CO², these typically warm-climate crops could thrive.

To make this work, Crapper & Sons plans to reshape the landfill. They’ll flatten parts of the site and build lined pits called “cells.” Waste will be placed into these cells to create gas. Once the gas is extracted, the remaining waste can be stored or processed further.

The greenhouses above the cells will be designed to move. That way, once a cell is used up, the greenhouse can shift, and new waste can be added below. This system makes the site reusable and avoids long-term contamination risks.

The plan also includes adding grass and trees to improve the site’s appearance and reduce its environmental footprint.

This project could help tackle several major challenges:

• Food security: By producing up to 80% of the local fruit and vegetable needs, it reduces reliance on imported food.
  
• Lower emissions: Using waste gas for energy and CO² reduces the release of harmful greenhouse gases into the atmosphere.
  
• Fewer food miles: Since the food is grown locally, it doesn’t need to be transported long distances, reducing emissions and costs.
  
• Efficient use of waste: The project reuses landfill gases and organic matter to create something valuable—fresh produce.
  

While the science behind the project seems solid, getting approval may be a hurdle. Mr. Ash said the biggest challenge isn’t technical—it’s getting people to accept a new way of growing food.

Growing food on a landfill may sound strange to some, but the team insists it will be safe, clean, and nutritious. Since the plants are grown without touching landfill soil, and CO² is filtered and monitored, the health risks are minimal.

The project, called the “Super Midden,” takes its name from an old archaeological term for ancient trash heaps. But instead of just studying old waste, this initiative aims to turn today’s trash into tomorrow’s food.

If successful, the Super Midden could become a model for other communities around the world looking to manage waste and food production more sustainably.