NRAs 2015 Best Food Waste Initiative: HMP Huntercombe

When it first started its waste management unit, it conducted an audit which revealed the need to address food first.

A wormery was built, housed inside a polytunnel to shield it from the elements. It was started with a small amount of compost before Dendra and tiger worms were introduced, which are best for this kind of composting. The wormery worked well for kitchen waste and a small amount of cooked food waste, but it could not cope with bones, cooked meats, fish and greasy foods.

To deal with this, the prison installed a Big Hanna T75 in-vessel composter and dewatering system with food collection buckets. Food waste is collected in buckets from the residential units, weighed, then processed through a macerator combined with a pulper. This reduces the initial volume of wet food by around 80% before being fed into the computer-controlled Big Hanna.

This then turns the food waste into a mature compost over a period of eight to 10 weeks. Compressed sawdust is added to the mixture to soak up any excess moisture. The resultant compost is bagged, sent to the garden department, stored until needed and used to grow the vegetables for the kitchen.

The prison’s food waste issue was further addressed by identifying what the food waste comprised. As a result, the kitchen changed its menus and prisoners – from 80 countries, with different religious, cultural and special dietary needs – were surveyed on diet, which led to more menu changes. Staff mess menus have also been reviewed.

“The holistic approach taken by the prison looked at the entire chain: creation, management, treatment and engagement. Lessons can be learned, not just in prisons but in many other sectors and at home on a small and large scale. Knowledge transfer was an important aspect.”

Judges’ comment    

A team of 20 prisoners prepares 95% of the food in-house, generating employment and education in catering. Menus are planned four weeks in advance and stock is rotated so food is used before it goes out of date. Portion control was implemented by using foil trays, which are separated after use and sent to a metal recycling plant.

A pilot separate food waste collection project is running in one resident house block, helping to reduce contamination of other waste streams. The changes have reduced food waste by 50%, generated more work for prisoners and saved money on purchasing stock.