At Europe's most modern plant for mechanical-biological treatment of domestic waste, in Lübeck, Siemens drive and control technology ensures maximum process reliability and availability.

The mechanical-biological waste treatment plant in Lübeck, Germany, which was developed and installed by specialists from HAASE, is the most modern solution of its kind in Europe. An innovative, highly efficient wet anaerobic digestion process is used, in which the organic part of the waste is transformed into a substrate suitable for direct disposal in landfills. The plant processes domestic waste, comparable commercial waste, and the region's bulky waste.

The waste is first shredded, and then it passes through a number of mechanical stations that remove recyclable elements from the mixed waste stream before converting it into a slurry that is slowly converted into a type of mash during the subsequent anaerobic digestion. At the end of the fermentation process, the mash is further decomposed and treated in the wet state by aeration in closed tanks. Then the fermentation residue is decanted and dried, producing a landfill substrate.

Mechanical pretreatment removes recyclable elements from the mixed waste stream (Photo: Siemens AG)

Flexible control

HAASE, a long-standing Siemens customer, implemented an integrated solution for the drive and automation technology at the Lübeck waste treatment plant, based on Totally Integrated Automation with Simatic S7-300 and S7-400 controllers in connection with Micromaster 430 and 440 series frequency converters. Because the composition of the received waste is constantly changing, the control and drive technology must be able to reliably analyze the crucial process parameters and respond flexibly to them. The necessary information for this is transmitted via a standardized communication network that includes Profibus, AS-Interface, Industrial Ethernet, and Industrial Wireless LAN through to GSM cellular communication networks. The system ensures a fully automatic process. This simplifies continuous in-process diagnosis, maintenance, and emergency service and also supports HAASE in the initial phases of productive operation. In addition, the standby service can intervene in any of the process steps from anywhere on the premises.

Remote diagnosis

In critical operating situations that demand prompt action, a text message is sent automatically to the HAASE standby service. There, the service technician can dial into the system directly, make an initial diagnosis, and take the necessary action without losing any time. This function is important both for the Lübeck waste treatment plant and for HAASE, which has installed plants all over Europe, because in some cases there is no time to be lost. In the event that the agitator in one of the large fermenting towers fails, for example, the problem must be solved within 24 hours. By then, the agitator must be running again. Otherwise the mash settles and may have to be excavated at an enormous expense and effort.

The soil-like substrate that leaves the biological treatment plant after drying is suitable for direct landfill disposal (Photo: Siemens AG)

Clear structures for high availability

Prompt service is important in guaranteeing the required high availability. However, the prerequisites for rapid elimination of faults also include clear, standard, and uncomplicated automation structures with good diagnostic and maintenance properties. In the HAASE systems, Micromaster drives, Simatic S7 controllers, and Siemens host computers are the central components of a clearly structured, uniform system environment that, with its standardized communication, makes a major contribution to the profitability of the Lübeck waste treatment plant.

(Photo: Haase)

The HAASE Group

The HAASE Group in Neumünster, Schleswig-Holstein, employs specialists in environmental technology and system design. In addition to mechanical-biological waste treatment, the HAASE company specializes in biogas, energy, and landfill process technology.

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