WEDECO Wins Order To Equip Munich's Gut Marienhof WWTP With A UV Disinfection System

Düsseldorf - WEDECO AG has won a major order worth more than 1.45 million euros from the "Stadtentwässerungswerke München" (municipal sewerage company) of the city of Munich. Germany's largest UV water disinfection system is to be built at the Gut Marienhof waste water treatment plant in Munich. The system is scheduled to be installed in the spring of 2005 and to start operation in the summer of the same year. The Gut Marienhof WWTP, located to the north of Munich, has been in operation since 1989 and is designed to serve a population equivalent of 1 million. After undergoing thorough biological and physical treatment, the wastewater is discharged into the "Middle Isar". The UV system will disinfect the wastewater during the summer months from 15 April to 30 September and will be switched off over the winter.

During the summer, the Isar valley serves as an important recreational area. This is especially true of the "Upper Isar", between the Sylvenstein reservoir in the south and the Bavarian capital city of Munich in the north. In the past, high bacterial concentrations and values in excess of the microbiological guideline and limit values defined in the EU Bathing Water Directive have been measured in this area. Bathers may be at risk. For this reason, bathing is officially forbidden in many stretches of the Isar. In other words, the Isar is not approved as a bathing area. In the mid 1990s, therefore, the Bavarian state government launched the "Improving the bathing water quality of the Upper Isar" project. This initiative was unique of its kind in Germany and Europe, and involved improving the biological water quality of the Isar and the Loisach through the targeted disinfection of the wastewater of the neighbouring municipalities. The objective was to enable the Isar to be used as a bathing area in conformity with the EU Bathing Water Directive.

The implementation of this ambitious environmental project required an investment of 5.03 million euros for sand filters and UV wastewater disinfection systems [1] in the six neighbouring municipalities so far involved – Lenggries, Bad Tölz, Wolfratshausen, Schärftlarn, Penzberg and Benediktbeuern/Bichl. Around 2.9 million euros of the UV investment costs were borne by the Bavarian state. The investment is now paying off. According to the Bavarian Water Management Agency (Landesamt für Wasserwirtschaft), there has been a marked improvement in the quality of the water in the upper Isar and the Loisach in the summer months, i.e. in the months when the UV systems are in operation.

The "Upper Isar" project is now being followed up by the installation of a large UV disinfection system at the Munich WWTP. In the "Middle Isar" area, i.e. below Munich, another four municipalities are now in the concrete planning phase. The Bavarian state is also subsidising this follow-up project. A total of 4.5 million euros has been made available within the framework of a special support program.

The ceremony of laying the foundation stone for the building measures took place today in the presence of Munich's Mayor Hep Monatzeder, representatives of the Bavarian Office for Water Management and dignitaries from the neighbouring municipalities.

Wastewater disinfection takes place at the Gut Marienhof WWTP in a total of six concrete channels in which almost 1,300 UV low-pressure Spektrotherm® HP lamps are installed. The Spektrotherm® low-pressure lamps are arranged in two banks and nine modules. The maximum wastewater flow is 21,600 m³/h of wastewater with a transmission level of at least 70%. The UV irradiation of the treated wastewater will keep the residual bacterial counts well below the guideline values of the EU Bathing Water Directive.

The lamps emit a UV dose of 450 J/m². Consulting engineers Schlegel GmbH & Co. KG are responsible for the realisation. The company has already carried out a number of projects for the installation of UV disinfection stages in the sewage treatment plants of the neighbouring municipalities of the "Upper Isar".

[1] Bavarian Water Management Agency

More about WEDECO:
WEDECO AG, headquartered in Düsseldorf, is the world's leading manufacturer of chemical-free water disinfection and water oxidation systems based on ultraviolet light and ozone. More than 200,000 systems represent a saving of more than 160,000 tons of chlorine each year and therefore make a considerable contribution to protecting health and the environment. The company is listed on the German stock exchange under WKN 514180 and has production sites in Germany, the USA, Italy, France, Hungary and Korea. WEDECO has more than 700 employees in 17 countries across all continents.

Source: WEDECO AG Water Technology