Design of aeration systems in activated sludge plants at different wastewater temperatures

摘要

The standard oxygen transfer rate (SOTR) is the decisive factor in the dimensioning of activated sludge plants. Itndepends on the required oxygen uptake rate (OUR) by microorganisms. The dependencies of the SOTR and OURnon the wastewater temperature (range 5–30 °C) are discussed. It is shown that the absolute values of the SOTRndepend only slightly on the wastewater temperature, while the specific values, in relation to the aerated tanknvolume, increase considerably as a function of the wastewater temperature. Within this context, the decisivendimensioning temperature is discussed. In addition, two design approaches for determining the SOTR,ntemperature-dependant and temperature-independent, are presented and compared, showing the impact ofnthe water dependency. Finally, the sensitivity of the decisive factors for determining the SOTR is discussed, particularlynaddressing the influence of the α-value.