Anaerobic digestion at Nestlé factory turns rejected chocolate into renewable energy

By Victoria White, New Food Magazine. 

A new anaerobic digestion system at Nestlé’s factory in Fawdon is turning chocolate and sugar confectionery waste from the site’s manufacturing processes into renewable energy and clean water.

Rejected chocolates and sweets which are not suitable for sale or reprocessing, along with waste residues such as starch and sugar are broken down in to small pieces. This mixture is then partially dissolved using the waste liquids from the site’s cleaning processes to create a ‘chocolate soup’. This ‘chocolate soup’ is then fed into an airtight tank where anaerobic digestion occurs. Anaerobic digestion is the natural process of bacteria breaking down biodegradable material, such as food, without oxygen, and converting it into useful by-products. These by-products are used to meet part of the site’s energy needs.