ABSTRACT
There has been a large volume of research on oxygen transfer which has helped to define factors affecting the design of aeration systems. There are, however, many misconceptions regarding the effects that high liquid temperatures have on the oxygen transfer process in both clean water and biological reactors. This chapter will discuss the effect of various mesophilic and thermophilic temperatures on dissolved oxygen saturation concentrations (beta factor), the overall mass transfer coefficient (alpha factor), and the temperature correction coefficient (theta factor). The operating performance of jet aerators over the past 12 years in both thermophilic activated sludge processes and autothermal thermophilic aerobic digesters will be discussed. In addition, the results of a performance evaluation of jet aerators and membrane diffusers will be presented. This comparison will show the oxygen transfer characteristics of the two devices operating in different temperature ranges.
Ongoing research by Mass Transfer Systems is being carried out to further define the effect of various components of the aerobic treatment on oxygen transfer performance. This is a continuation of previous work conducted in conjunction with Northeastern University 1 , 2 and now being continued in association with Purdue University. 6
