Water & Wastewater Treatment Magazine
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22 | NOVEMBER 2017 | WWT | www.wwtonline.co.uk The Works: sludge and energy One of the advantages of the ATC gasi cation process is that it does not require aggregation in order to be e cient: unlike advanced anaerobic digestion, which is best used at a large hub site drawing in sludge from many locations, it could be deployed at numerous smaller wastewater treatment sites, near the points where the sludge is produced and the energy is used, cutting down on transport costs. Moreover, these installations can be controlled remotely, and visited periodically for maintenance rather than manned round the clock. The technology could therefore have far-reaching implications when considered in the light of Ofwat's reforms to create a deregulated sludge market in 2020. While much of the commentary around these reforms has focused on moving sludge between areas and making use of spare capacity, the widespread deployment of technology such as gasi cation could mean that the future of sludge-to-energy is much more local. The apparent solid investment case could lead third-party companies and investors to set up ATC plants to take sludge from wastewater treatment sites and sell the energy back to the water company, to nearby industrial users, or the grid. This model would potentially be pro table for the entrant company, and provide the water utility with cost savings, sludge disposal and sustainability bene ts. Water companies themselves are unlikely to roll out gasi cation assets speedily a€ er PR19, since they have many functional and relatively new anaerobic digestion assets and replacing them will not be a priority. However, with Yorkshire Water's eˆ orts proving that the technology works, some deployment in AMP7 is likely, and gasi cation could then nd itself a mainstream option, which is in pole position when AD sites need replacement in AMP8 and beyond. On the back of the demonstration plant's success, Enertecgreen will also be able to market the gasi er technology around the world. "This has been a real partnership with Yorkshire Water, and their commitment to the technology and its use on an industrial scale has been invaluable for us," says David Pitt, director at Enertecgreen. "A€ er 10,000 hours of operations here, with highly e cient conversion and very clean performance on the engines, we've met all of the goals we set ourselves from a scienti c and R&D perspective; the boxes are all ticked. "Everyone we've spoken to has expressed real interest in nding out about the plant and what we are doing here: Germany has huge potential, and we've had particular interest from Scandinavia," continues Pitt. "Anaerobic digestion plants will not be thrown away overnight - AD works, and in certain situations very successfully - but ATC gasi cation will be seen as complementary to other technologies in this space. It can deal with some sludges that AD can't deal with, it produces a lot of heat, which can be used in drying processes as well, and it helps avoid sludge to land. The power is produced locally, the expectation is that it's used locally, and that's ultimately going to provide a lot of value in terms of both cost and carbon savings." ˜ THE IMPLICATIONS Yorkshire Water Manager of Innovation Jon Brigg inspects the gas quality from the gasifi er www.wwtonline.co.uk around the world. about the plant and what we are doing here: Germany has huge potential, and we've had particular interest from Scandinavia," continues Pitt. "Anaerobic digestion plants will not be thrown away overnight - AD works, and in certain situations very successfully - but ATC gasi cation will be seen as complementary to other technologies in this space. It can deal with some sludges that AD can't deal with, it produces a lot of heat, which can be used in drying processes as well, and it helps avoid sludge to land. The power is produced locally, the expectation is that it's used locally, and that's ultimately going to provide a lot of value in terms of both cost and carbon savings." Project Manager John Shepherd with some of the sludge pellets