2012|13 Annual Report Fraunhofer IGB

114 SYSTEM DESIGN FOR THE TREATMENT OF WASTEWATER FROM VINIFICATION Dr.-Ing. Tosca Zech Heavily loaded industrial wastewater from viniﬁcation Wastewater from viniﬁcation contains very high concentra- tions of organic carbon compounds. Therefore, they are espe- cially suitable for energy recovery by fermenting energy-rich compounds into biogas. In Germany, wastewater from viniﬁ- cation is mostly co-treated in municipal wastewater treatment plants because with few exceptions the annual volume of this wastewater is less than the annual volume of wastewater from an average household. However, wastewater from vi- niﬁcation is mainly produced in autumn after harvesting and wine production. Due to the multitude of wineries as well as wastewater volume and composition, in wine-growing re- gions (Fig. 1) many wastewater treatment plants have to face problems during operations and additional costs [1], like in the collective municipality Edenkoben on the southern German Wine Route in Rhineland-Palatinate. The aim of our investigation was the determination of a pro- cess concept for the management of loads of the wastewater treatment plant of Edenkoben by construction of decentral- ized pre-treatment plants and the creation of storage capaci- ties in the bigger wine companies and cooperatives. Our ap- proach takes into consideration the whole process chain from wastewater production during viniﬁcation, wastewater dis- charge and wastewater treatment to sludge treatment and disposal. By taking into account technological, economic and ecological aspects a concept for the decentralized anaero- bic treatment of wastewater from viniﬁcation was designed across organizational and geographic boundaries (Fig. 3). Decentralized anaerobic wastewater treatment for biogas production According to our concept drinking water used in the process of viniﬁcation is distributed economically in order to save costs for the wine company and to maintain high concentrations of organic compounds in the wastewater produced. Further important principles during production are solid separation to a great extent (grape marc is recycled in agriculture) and economic use of cleaning chemicals for the protection of mi- croorganisms of biological wastewater treatment. Produced wastewater with a chemical oxygen demand (COD) of more than 6000 mg/L is buffered in mixing and equalizing tanks. The core is the decentralized anaerobic wastewater treatment plant for pre-treatment (Fig. 2). Anaerobic microorganisms are producing biogas and reducing COD up to 90 percent in a one-stage plant (Fig. 4). The biogas (methane) is directly uti- lized and burned in a combined heat and power plant. The decentralized thermal utilization of bioenergy ensures high power efﬁciency and substitutes parts of conventional oil ﬁring. During anaerobic biological wastewater treatment little sur- plus sludge is produced that can be directly recycled in agricul- ture. Treated wastewater can be discharged into the municipal wastewater treatment plant without further costs for compa- nies in terms of green taxes on heavy pollution. Professional operation of the plant is ensured by applying a BOT model. Our own measurements have conﬁrmed that wastewater from the chosen wineries is especially suitable for anaerobic pretreatment. COD concentrations are typically between 6000 and 16,000 mg/L. At the same time nutrient concentrations are comparatively low. 21 ENERGY

2012|13 Annual Report Fraunhofer IGB

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