More Efficient Anaerobic Digestion
Nestlé’s Fawdon factory in the UK is using a new anaerobic digestion system to turn chocolate and sugar confectionery waste from the site into renewable energy and clean water.
The system involves mixing rejected chocolates and sweets that are not suitable for sale with waste residues such as starch and sugar and partially dissolving them with waste liquids from the site’s cleaning processes to make a ‘chocolate soup’. This mixture is fed into an airtight tank where anaerobic digestion occurs.
The by-products of this process, including biogas, a renewable gas comprised largely of methane and carbon dioxide, can be used to contribute towards the site’s energy demands.
This technique has been used in agriculture and industry for centuries, but the Fawdon system has been adapted to handle a high volume of solid and liquid waste within a short time.
“The system allows us to add tougher residues like starch-based compounds to the process, along with reject product and other materials,” says Inder Poonaji, Nestlé UK and Ireland’s head of sustainability.
“As long as the material is biodegradable, the anaerobic conversion process can take place. The waste we are converting here would otherwise be disposed of externally.”
Article cited from: http://goo.gl/H0vSmo