Fixed bed is the most frequently used operation for ion exchange and adsorption and although highly useful and utilized, its engineering analysis is quite complex. A predictive model for fixed bed systems requires extensive experimental information, complex mathematical tools and in many cases, for complicated wastewater, the full modeling of the process maybe extremely difficult. The situation is even more difficult considering the maldistribution, as well as the scale up procedures. It is true that the overall effectiveness of a fixed bed operation depended mainly on its hydraulic performance. Even if the physicochemical phenomena are well understood and their application in practice is simple, the operation will probably fail if the hydraulic behavior of the reactor is inadequate. These effects could be critical not only in full scale but also in pilot or even in lab scale reactors. In the present study – composed by two parts – short cut methods is proposed as a first design tool. The methods essentially propose the use of a minimum number of experimental data along with some scale-up and hydraulic-performance considerations, extracted from the related literature. In part I of the study the theoretical models and hydraulics of fixed bed operations are presented. In part II the issues of scaleup and approximate design methods are presented.
