Sorters close the loop

A partnership between food waste disposal firm Swancote Energy and recycling equipment manufacturer TOMRA Recycling marks the first UK application of optical sorting technology in an anaerobic digestion facility.

TOMRA autosort

In 2021, the firm invested in an AUTOSORT® unit from TOMRA Recycling at its AD facility in Bridgnorth, Shropshire. It produces energy from a combination of commercial food waste and purpose-grown energy crops. CHP generators convert the biogas into electricity and heat, with the electricity fed directly to a local aluminium smelting company.

The AUTOSORT® unit is enabling Swancote Energy to recover recyclable plastic packaging from commercial food waste which can then be used in the production of new food-grade plastic packaging.

The plant’s infeed stream comprises of palletised food waste from multi-national food manufacturers, retailers, distributors and small independent businesses. Many different types of food waste are processed at the plant, including loose, liquids and palletised. The infeed stream contains a wide range of packaging materials such as plastics, tins and glass.

Swancote Energy uses a number of different mechanical and automated processes to recover all recyclable products for recycling, including glass, tin cans, aluminium products and plastics.

The firm can now process 50,000 tonnes per annum of palletised food waste while ensuring the rigid plastic packaging – including HDPE, PP and PET bottles, tubs, trays and pots – is all recovered for resale. The organic matter is removed first before the material goes through a hot wash prior to being optically sorted. The AUTOSORT® unit is the final stage in the process of depackaging of the food. Once recovered, the recyclable plastic packaging is sold on to food-grade plastic recycling facilities.

The AUTOSORT® combines near infrared (NIR) and visual spectrometers (VIS) to recognise and separate different materials according to their material type and colour, extracting high-purity high-value end fractions. At Swancote’s facility, the unit is programmed to target and sort rigid plastics by colour and polymer from the infeed stream, with the target fractions being HDPE, PP and PET.