Document Type


Publication Date

January 1981


Four, four-stage, laboratory scale rotating biological contactor (RBC) units were employed to develop kinetic models for the RBC process when treating domestic wastewater. The study was conducted at three different temperatures of 5 degrees C, 15 degrees C, and 20 degrees C. Each unit operated at a different constant organic loading rate taht ranged from 4 qCOD/m^2/d to 14 gCOD/m^2/d and at a constand detention time of 2 hours. Carbonaceous substrate removals measured as COD cencentrations with the four-stage RBC's were 80, 85, and 90 percent for 5 degrees C, 15 degrees C, and 20 degrees C, respectively. The major part of the removal occurred in the first stages. The overall precentage removals of ammonia nitrogen were 87 to 98 percent at 15 degrees C from 91 to 99 percent at 20 degrees C depending upon the influent organic loading rate. At 5 degrees C there was no ammonia nitrogen removal. Kinetic models were devloped and kinetic constants were determined for COD and ammonia nitrogen removal in the first and succeeding stages of the RBC units. Biomass yeild, biomass stabilization, and ammonia nitrogen removal were also evaluated. Monod growth kinetics were used in the development of the models for carbonaceous substrate removal in the first stages and for ammonia nitrogen removal in the system. The temeprature dependency of each kindetic constant was determined for the range of 5 degrees C to 20 Degrees C. Steady-state kinetic models were developed, and kinetic constants were determined as a function of temperature to provide a rational design approach for the RBC process treating domestic wastewater.