Showing papers by "Guanghao Chen published in 1996"

Determination of diffusion layer thickness on a biofilm

Abstract: This paper has proposed two models to determine the thickness (Lo ) of the diffusion layer on the biofilm surface. The first is based on the steady‐state organic removal flux in a biofilm reactor, and on the bulk organic concentration when oxygen is not limiting. The model has been verified by the experimental data from a submerged RBC. This mode indicates that organic removal flux increases sharply with a decreasing Lo, especially when it is greater than 50 μm. The second model is developed by establishing a relationship between the average flow shear velocity (U) along the biofilm surface and the Lo value. This model provides a simple way for Lo determination since it only requires the measurement of the U value. A comparison of this model is made with other reported formulas in the literature. Whenever the U value is above 3 cm/s it has the same trend as reported ones. However, at a lower U, it gives a much gradual increase of Lo as compared to others.

Prediction of oxygen limitation in an aerobic biofilm reactor

Abstract: This study is aimed at developing a determining model for predicting the critical bulk dissolved oxygen (DO) concentration for onset of oxygen limitation in a biofilm reactor with respect to a given bulk substrate concentration. Oxygen and substrate profiles within biofilms were examined through a numerical analysis of a mathematical biofilm model for evaluating the relationship between these two concentrations. It has been found that the critical bulk DO level (Cb) is directly proportional to the bulk substrate concentration (5 b ), which can be expressed as C, < 0.065 Sb for the onset of oxygen limitation. This oxygen limitation determining model has been verified with experimental results with a submerged RBC reactor.