On the design and operation of primary settling tanks in state of the art wastewater treatment and water resources recovery.

In state of the art wastewater treatment, primary settling tanks (PSTs) are considered as an integral part of the biological wastewater and sludge treatment process, as well as of the biogas and electric energy production. Consequently they strongly influence the efficiency of the entire wastewater treatment plant. However, in the last decades the inner physical processes of PSTs, largely determining their efficiency, have been poorly addressed.

Analysis of suspended solids transport processes in primary settling tanks.

The paper shows the results of a long-term research comprising FLUENT-based numerical modeling, in situ measurements and laboratory tests to analyze suspended solids (SS) transport processes in primary settling tanks (PSTs). The investigated PST was one of the rectangular horizontal flow PSTs at a large municipal wastewater treatment plant (WWTP) of a capacity of 500,000 population equivalent. Many middle-sized and large WWTPs are equipped with such PSTs.

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).