Two methods of biological treatment design.

soluble and nonsettling particulate organic material in wastewaters into a settleable floe. A number of techniques have been used to design the process. These techniques have been based on lab oratory, pilot plant, and field experience. The purpose of this paper is to compare the commonly used food : microorganism (f:m) design technique with the more recently proposed solids retention time (srt) design technique for biological treat ment of an industrial wastewater. A lab oratory study was performed on an oil refinery wastewater to obtain the desired design data. These data will be used in this paper to compare the application of the two design techniques. The use of these design techniques for nitrification, denitrifi cation, and anaerobic digestion designs will also be discussed. Background