Predicting reactor biomass concentration in a fluidized-bed system

Abstract

A new fluidized-bed process for wastewater treatment is an adaptation of the fixed-film biological reactor. As part of a development and demonstration program, a number of pilot plants and treatibility units have been designed and built for operation in the U.S., Canada, and other countries. The principal advantage of the fluidized-bed process is a reduction in reactor size caused by the development of high concentrations of biomass. By development of a hydraulic model for the fluidized-bed reactor on the basis of the principles of liquid-solid fluidization, a theoretical value for the reactor biomass concentration may be determined. A design basis for the system may then be formulated by combining the hydraulic model with a model for the biofilm kinetics. This paper presents information on the development of a hydraulic model for the system and reports on the results of applying the model to predict the biomass concentration observed during operation of two of the pilot plants. One of the pilot plants is a 0.37-m/sup 2/ (4-sq ft) rectangular fluidized-bed reactor 4.4m (14.5 ft) high, which is located in Cedar Rapids, Iowa, treating high-strength carbohydrate wastewater. The other pilot is a 2.22-m/sup 2/ (24-sq ft) rectangular reactor 4.4m (14.5 ft) high,more » which is located in Orillia, Ontario, Canada, treating primary municipal wastewater.« less