EXTENSION OF THE VIENNA MAIN SEWAGE TREATMENT PLANT

摘要

Vienna, the capital of Austria, is situated on both sides of the Danube River (mean discharge ～1700 m~3/s), and has an actual population of about 1.6 million inhabitants. The wastewater is collected in the city mostly by a combined sewer system, which is served by the Main Treatment Plant of Vienna (MTPV). The plant is designed for a pollution load of 2.9 million population equivalents (PEs). The actual plant went into operation in 1980 as a mechanical biological treatment plant. The legal requirement (permit) was to reach a BOD effluent concentration of 70 mg/l. The biological treatment therefore consists of a high-load activated sludge process (sludge age ～ 2 d). The actual pollution influent load is about 3.3 million population equivalents, i.e., about half of the pollution load is derived from trade and industry. The wastewater can be characterised as relatively concentrated typical municipal wastewater (BOD_5 > 300 mg/l). The sewage sludge production (～200 t DS/d) of the plant is incinerated on site and ashes go to landfill. The plant does neither meet the EU requirements for normal areas nor the corresponding more stringent Austrian minimum requirements to be met by 2005 at the latest. In order to meet the above mentioned requirements the MTPV is being extended for a pollution load corresponding to 4 million PEs. After completing the extension, the total wastewater from the city and several neighbouring municipalities will be treated at this plant (maximum dry and wet weather flows of 9 m~3/s and 18 m~3/s, respectively).