Germany's largest ultraviolet (UV) water disinfection system will be built at the Gut Marienhof wastewater treatment plant in Munich by the summer of 2005.
Wedeco Ag of Düsseldorf won the major g1.45 million order from the municipal sewerage company of Munich (Stadtentwässerungswerke München). The plant is designed to serve a population equivalent of one million. Wastewater will undergo biological and physical treatment before it 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.
In the mid-1990s, the Bavarian state government launched an ambitious project to improve the bathing water quality of the Upper Isar river, which involved a g5 million investment for sand filters and UV wastewater disinfection systems in six neighbouring communities - Lenggries, Bad Tölz, Wolfratshausen, Schärftlam, Penzberg and Benediktbeuern/Bichl. According to the Bavarian Water Management Agency, the investment is paying off, noting a marked improvement in the biological water quality of the water in the upper Isar and the Loisach in summer months when the UV systems are in operation.
The Upper Isar project is now being followed up by the installation of the large UV disinfection system at the Munich wastewater treatment plant. In the Middle Isar area, below Munich, another four municipalities are now in the concrete planning phase.
Wastewater disinfection will take place at the Gut Marienhof facility in six concrete channels in which almost 1,300 UV low-pressure Spektrotherm® HP lamps are installed. 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.