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Ruhleben wastewater treatment plant treated 85 million m³ of wastewater in 2015. It is the largest of Berlin’s six wastewater treatment plants and the only one with its own sludge incineration

Process control system

The future begins now

During its 20-year service life, Teleperm M enabled the reprocessing of 220 million m³ of wastewater per year at the Berliner Wasserbetriebe wastewater treatment plants. The 104 automation systems have now been converted to the Simatic PCS 7 process control system, thus ushering in a new era at one of Europe’s largest water supply and waste disposal companies.

Every day, Berliner Wasserbetriebe supplies almost four million people with fresh water and removes and treats wastewater. The company supplies 585,000 m³ of drinking water to households, industrial plants, and businesses every day. And with the aid of 150 pump stations, a 9,500 km sewer network transports 600,000 m³ of wastewater every day to six wastewater treatment plants for purification so that it can be ­returned to the cycle of nature. 

For more than 20 years, the sewage treatment plants were successfully automated with the Teleperm M system from Siemens. Then, over a period of seven years, a major proj­ect migrated the 104 Teleperm  M automation systems to the latest Simatic PCS 7 process control system. The aim of this project was to modernize the technical foundation of the process control technology so that all the plants would run on a uniform, largely standardized platform. The company wanted the technological content of the old software to continue being used, in an automated manner and preferably without reprogramming. The existing control and monitoring system also needed to be compatible. Special emphasis was placed on ensuring that the ongoing operation of the wastewater treatment plants would be disrupted as little as possible during the migration and that under no circumstances would the automated operation be interrupted for more than eight hours.

The project requirements specified in the call for tenders in 2006 were therefore demanding. Berliner Wasserbetriebe carefully examined all tenders. In the end, Siemens was awarded the commission for the migration in 2007.

The OWA Tegel surface water treatment plant was also equipped with new control technology during the course of the migration project

Carefully planned migration

The project began in 2007 with the first automation systems at the OWA Tegel surface water treatment plant and the Stahnsdorf waste­water treatment plant. To increase operational safety, the actual migration of each automation system was divided into several stages: First, the software assets were ­analyzed, optimized, and prepared for the automatic conversion by Berliner Wasserbetriebe. Then the software version was migrated at Siemens. In the next stage, the project team replaced the central modules of the process control system and installed Simatic PCS 7 / Teleperm modules as an interim solution. This enabled operation with the existing Teleperm I/O devices to continue. The team then replaced the Teleperm I/O devices with Simatic ET 200 systems and installed new distribution boards. “We had very little time available during which we could interrupt operation for the exchange,” says Uta Pachaly, who is responsible for the process control technology of wastewater treatment plants at Berliner Wasserbetriebe and was also the project manager for the migration. “Then gradually – drive by drive – we switched everything back on again, and after three to six hours the plant was back in ­operation.” This tight schedule ­required the teams to be well prepared and to exercise great care, as one of the steps required for each migration was the manual reconnection of up to 10,000 connections. The necessary preconditions had already been created in an earlier project, from 2003 to 2005, during which previously different operating and monitoring systems in the control stations of the five wastewater treatment plants and OWA Tegel were unified and standardized. “Because of the uniform operator interface prepared for the migration in the earlier phase, the employees in the control room did not see this migration on the monitors – plant operation was exactly the same after the migration as before,” explains Pachaly. Following a successful transition at the first plants in 2008, work was completed at the Schoenerlinde wastewater treatment plant in June 2010, followed by the Wassmannsdorf and Ruhleben plants.

Sustainable result

Beginning in 2007, plant docu­mentation was created using the Sigraph documentation system. This documentation can now be maintained and carried forward with minimal effort. The result is a modern process control solution at OWA Tegel and the five waste­water treatment plants that is based on standardized hardware and software.

The project was extremely successful, and the Berliner Wasserbetriebe staff particularly praised the management of the automated program conversion as well as the adherence to schedule and the outstanding partnership with the engineers on the Siemens project team. The CEO of Berliner Wasserbetriebe, Joerg Simon, put it in a nutshell at the celebration marking the completion of the project: “Everything is new and no one has noticed.” It is hard to imagine a more satisfactory result for a migration.

Picture credits: Berliner Wasserbetriebe