Recycling process

In-vessel/windrow Composting
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Collection: Food and garden waste is collected from the kerbside or recycling centres and taken to a composting facility.
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Shredding/Storing: The food waste is shredded and mixed with the garden waste, before being placed in either large sheds (vessels) where moisture content, air flow and temperature can be controlled, or heaps (windrows) no more than 1.5m high and extended lengthways.
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Heating/Turning: The waste is left in the vessels for seven days. Temperature probes ensure that there is sufficient heat to kill dangerous bacteria – it must achieve 60degC for two consecutive days. In windrow composting, the windrows are turned regularly so that all materials spend some time in the warm, moist centre of the heap.
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Maturation: The waste is then transferred to a maturation pad for final stage composting. The entire process takes about eight weeks.
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Finishing: The resulting compost is then used in parks, public gardens or in agriculture

Anaerobic digestion
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Collection: Food and garden waste is collected from the kerbside or recycling centres and taken to an anaerobic digestion facility.
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De-contamination: The food waste is tipped into a designated tipping area, where the material is inspected and contaminants are removed.
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Shredding and pasteurisation: The waste is then shredded and fed into the digestion process in sealed tanks called digesters. The material is then pasteurized to ensure all pathogens and bacteria are killed.
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Digestion: The digesters are completely sealed to create an oxygen free environment. The digesters are fed by a pumped pipework system. The material is digested at 55degC to produce biogas and a compost-like product (digestate). This process takes about a month.
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Gas extraction: Biogas is produced and extracted from the top of the digester. It is taken to a Combined Heat and Power (CHP) unit to generate energy. The heat is captured for on-site use, while the electricity provides on-site power and is sent to the local electricity network.
- Digestate: The remaining product is a nutrient-rich biofertiliser. This must meet PAS 110 standards to be used freely as a fertilizer.
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