LAWR

ENERGY FROM WASTE 24 Local Authority Waste & Recycling June 2015 Warmth of waste makes tomatoes grow The efficiency of energy-from-waste plants can be improved through heat capture. Has the public sector now recognised its vital role in developing the required infrastructure, asks Keith Riley. aste and food are usually only associated with one another when what we fail to eat is thrown away. But that might be about to change, at least if companies like Suez Environnement have anything to do with it. A project is underway at the firm's energy recovery plant at Great Blackenham in Suffolk. There, a pipeline is being built that will take heat from the plant and deliver it to two nearby greenhouses. These aren't just any greenhouses either: they cover nearly 50 acres of land and will produce around 7,000 tonnes of tomatoes a year (10% of Britain's total). This project is currently the exception W rather than the rule, but heat from waste is becoming a hot topic. There are a number of reasons why. Improved efficiency It has long been possible to turn food waste into compost or digestate to help grow more food, but capturing that waste separately is difficult; much of it remains in the black bag stream (even when separate food waste collections are available). If landfilling – with its associated greenhouse gas emissions – is to be virtually eliminated then using thermal treatment to recover the energy in the residual stream is a must. To make energy recovery really effective, however, it is not sufficient just to burn waste using a simple boiler and turbine. The average modern energy-from-waste (EfW) plant processing, say, 250,000 tonnes per year, converts only around 25% of the energy in the waste into electricity, and smaller schemes are considerably less efficient than that. So how can the efficiency be improved? Using more complex equipment to extract the heat from the steam is one option. Gasifying it and using the syngas to fire an internal combustion engine or gas turbine is another. Alternatively, some of the heat can be exported for use on another site. Recycling energy as heat – through so-called combined heat and power (CHP) – is actually quite simple. In fact, Thomas Edison built the world's first commercial power plant in Manhattan in 1882, and sold its BOa: The green way of recycling! energy savings? BOa ecOline Impress baler Our impress baler's, M and D Series, can be delivered with steel wire tying and PP twine tying, combined on one machine. Boa Recycling Program We develop and deliver among other: • Balers (Impress®, Continette, Baseline) • Bag openers • Shredders • reel Splitters • conveyors The BOA BAler Type ecOline cAn reduce pOwer cOnsumpTiOn By up TO 60%. BOa recycling equiPMenT BV T +31 (0) 534 300 300 e infO@BOarecycling.nl www.BoaRecyclIng.com We manufacture bespoke Shredders for Shredding... \Clinical Waste \Tyres \Metal \Mobile Shredding \Plastics \Confidential Documents \WEEE \Electronic Media Storage Devices \Textiles \Organic Waste \Fuel Large, coarse, superfine and everything in between at Ulster Shredders. Cogry Works, 65 Creagh Rd, Castledawson Magherafelt. BT45 8EW T. +44 28 7965 0050 F. +44 28 7965 0025 Want to find out more about our range of Industrial Shredders? Email us at info@ulstershredders.com or visit our website. ulstershredders.com Warmth of waste makes tomatoes grow

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