Data: September 2022
Info: Floating cover for digestate tank diam 64m.
As an evolution of the 2016 project to cover a 64m-diameter storage tank, a floating roofing system was developed, resting on floating polyethylene elements hooked together to form a rigid platform. The roofing membrane, made in one piece to cover about 3600 square metres and weighing about 5 tonnes, was laid and rolled out using about 20 people. The system is covered by a patent application filed in August 2022 and is designed to replace traditional truncated cone structures covering digestate tanks. In fact, the cover has countless environmental advantages over traditional covers. Firstly, floating on the surface of the fluid, there is no variation in the volume covered depending on the level of filling of the tank. This allows the capture of gas, which accounts for about 10% of the entire plant’s production. The structure is totally gas-tight, minimising emissions into the atmosphere also thanks to the slight negative pressure at which the gap between the sludge and the cover is maintained. The structure is also totally impermeable to rainwater, which is therefore collected by the cover and pumped out of the tank without the risk of leaching the sludge with consequent pollution of the same and lengthening of the reclamation process.
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