2012|13 Annual Report Fraunhofer IGB

113 Dr.-Ing. Werner Sternad Phone +49 711 970-4110 werner.sternad@igb.fraunhofer.de Barbara Waelkens M.Sc. Phone +49 711 970-4124 barbara.waelkens@igb.fraunhofer.de References [1] Fricke, K. (2009) Energieefﬁzienz kommunaler Kläranlagen. Hrsg. Umweltbundesamt [2| Sternad, W. (1991) Bioreaktoren. In: Chmiel, H. (Hrsg.) Bio- prozeßtechnik, Fischer-Verlag, Stuttgart Project partners ZWA Bad Dürrenberg | Ingenieurbüro Stockleben GmbH, Bad Dürrenberg | Eisenmann Anlagenbau, Holzgerlingen loop reactor [2]. However, there had been hardly any experi- ence at the necessary scale of approximately 360 m3 reactor volume. Calculation of the gas lift loop reactor Through careful simulation calculations and analysis of the necessary hydraulic and geometric data, we were able to ﬁnd a solution which required the precise observation of the speci- ﬁcations for the geometry of the reactor and the draft tube. For this reason the geometric data was repeatedly checked during the construction phase. Operating results and outlook Immediately after the inoculation in May 2012 it became ap- parent that high-load digestion with gas injection works very well hydraulically as a gas lift loop reactor. To date there have neither been any problems with the formation of foam nor of a scum layer. The amount of sludge gas generated met the expectations. In Bad Dürrenberg the simpliﬁed design of the high-load digestion plant as a gas lift loop reactor resulted in savings of 100,000 to 200,000 euros. The conversion of the ABA Bad Dürrenberg from simultaneous aerobic to anaerobic sludge stabilization while the plant was operating was possi- ble due to the excellent cooperation of all parties involved. Particularly for population equivalents of between 10,000 and 50,000 there are a lot of wastewater treatment plants which had originally been planned as aerobic stabilizing plants and whose conversion would be worthwhile from an economic point of view. 1 Foundations for the gas storage (left) and the high-load diges- tion installation (right in the rear). 2 Construction of the high-load digestion plant. The reactor is lifted above the draft tube. 3 High-load digestion with scaffolding for the assembly of the pipelines, sensors and insulation. 4 Commissioning of the double-membrane gas storage. 5 Professor Hirth giving his speech during the ofﬁcial dedication. 6 View of the ﬁnished and insulated high-load digestion plant. 4 5 6 Contacts

2012|13 Annual Report Fraunhofer IGB

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