Data: 2013
Info: Sewage storage tank cover - 52x47m
The storage tank for wastewater (digestate) from a biogas production plant must be covered to prevent rainwater contamination and to recover the gas created by the large, still-active mass. Traditional solutions based on conical covers with a single central pole work well for circular tanks up to a maximum of 35 meters, but are ineffective for rectangular tanks with larger spans. Any type of load-bearing structure used to support the textile cover must be made of stainless steel due to the highly corrosive environment. For this reason, a cover was created using inflatable beams 3 meters in diameter and 47 meters long, each supported by two stainless steel cables. The beams are 100% textile, minimizing the amount of materials subject to corrosion. Furthermore, being inflatable, they float, allowing the cover to be installed when the tank is full. This system allows the roofing to be tensioned by inflating the beams and, in the event of heavy snowfall, allows the structure to be deflated and floated on the sewage. The load-bearing beams are monitored through a remote control system that allows viewing the pressure and the number of inflations occurred in a given period of time.
Sewage basins need to be covered to prevent rainwater pollution, avoid bad odors, and collect the biogas that might be produced. If the basin span exceeds 35 m, and/or if its shape is rectangular, standard systems based on cone shapes cannot be applied any further. Moreover, due to the aggressive gas produced beneath the covering, the use of stainless steal truss beams is mandatory, which means increased costs both for materials and for the assembly phase. Inflatable beams technology is the cost effective solution to the problem of covering large basins. Inflatable beams ensure the slope for the flowing of water and, at the same time, contribute to the pre-tensioning of the external cover. Beams are monitored and controlled remotely with “black box” which guarantee the pressure level.