above: Arabella Hotel in Offenbach middle: Control panel, left RBC group, secondary settling tank below: Primary settling tanks, right RBC group

Pilot plant in Berlin We developed several graywater plants in Block 103, Berlin-Kreuzberg, in cooperation with STATTBAU, an ecological program financed by the state of Berlin and the Federal Ministry of Building. These plants have been in operation since 1989 and have been investigated and optimized extensively by the Department of Hygiene of the Technical University of Berlin. The results of many years of research have been invested in the development of these graywater plants. EXPO 2000, Hannover The German construction company BauBeCon and the local public utilities erected a graywater experimental park in Hannover, Hägewiesen. A graywater plant with a two-stage RBC (rotating biological contactor) was erected to provide for 6 housing units, and its successful operation has been documented by the municipal wastewater / drainage works since November, 1994. 4-star hotel 'Arabella' Commissioned by the Bavarian Industrie und Gewerbe Bau GmbH & CO, Munich, a six-stage graywater plant, one of the first of its kind worldwide, was installed in the 4-star hotel 'Arabella' for 400 beds. With a cleaning capacity of 20,000 liters a day, this plant has been in operation since January, 1996. Demonstration plant in Kassel A two-stage RBC, sized for 60 individuals, was erected in Kassel-Hasenhecke for 'Wohnstadt', the largest housing construction company in North Hessen. This plant has been in operation since the spring of 1996, and is being compared with rainwater reuse plants in a program initiated by the state of Hessen to compare water-saving technologies.