Urban wastewater development in Central and Eastern Europe.

In the early nineties the region of Central and Eastern Europe (CEE, more than 1 million km² and 100 million inhabitants) went through fundamental political, economic and social changes which eventually led to the European integration process. This positively influenced urban water and wastewater management , which had an unbalanced structure and rather low level of development. The paper outlines first the 1990 situation (water supply, sewerage and wastewater treatment (WWT)) and the infrastructure development of the last two decades, on the basis of a comprehensive data collection for six countries (Bulgaria, the Czech Republic, Hungary, Poland, Romania and Slovakia). Austria serves as a reference basis. Alterations of some of the drivers such as GDP (Gross Domestic Product), water tariff, investment funding and legislation are studied in detail. Then, the paper focuses on WWT by analyzing data of 20 large plants. Influent and effluent quality is evaluated. Technology indicators are estimated and assessed. They include plant removal rates and violation ratios assuming the application of the Urban Wastewater Directive, primary clarifier removal rates, actual anoxic volume and sludge age in comparison with the recommendations of the ATV guideline, criteria of secondary settling tanks and energy consumption. Finally, nutrient removal rates and upgrading options are outlined.