ADAPTION OF THE MAIN WASTE-WATER TREATMENT-PLANT IN VIENNA TO MEET AUSTRIAN EMISSION REGULATIONS

The modification of the main waste water treatment plant in Vienna wil l take place in accordance with the minimum efficiences laid down in t he emission regulations as issued in 1991 by the Austrian Federal Offi ce for Agriculture and Forestry. To meet these figures it is necessary to adapt the plant by 2001. The studies on several variants and the e valuation process showed a 2-step technology with partial by-passing o f the Ist step to be the optimal solution. For this flexible system a new aeration tank volume of only 210,000 m(3) is sufficient. Test-runs with a semi-commercial plant confirmed the correctness of all calcula tions. Possibilities for further modifications have been considered, e .g. dimensioning of all relevant hydraulic installations up to 24 m(3) /sec, final purification by sand or flocculant filtration and spare ar eas for measures after 2015. Copyright (C) 1996 IAWQ. Published by Els evier Science Ltd.