Environmental Engineering Research Center, School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
Abstract:
In a steady state biofilm culture, dissolved organic carbon (DOC) distribution between catabolism and anabolism can be described by a ratio of the DOC channeled into carbon dioxide (SCO2) to the DOC converted into biomass (Sg). Based on a balanced oxidative reaction of DOC, a SCO2/Sg-dependent observed growth yield (Yobs) model was developed for biofilm culture and was verified with literature data. Growth and detachment forces are two decisive factors in biofilm process. The detachment force (Df) normalized with respect to the growth force (Gf) was introduced to describe the interaction between the biofilm growth and detachment processes. Biofilm metabolism and structure were closely related to the Df/Gf-ratio, and biofilm community could metabolically respond to changes in growth and detachment forces. A proper balance between growth and detachment forces is crucial for development of a compact and stable biofilm. The proposed Df/Gf concept provides a theoretical basis for experimental data obtained at different growth and detachment forces to be interpreted in a unified sense. Biofilm structure may be manipulated by controlling the Df/Gf ratio.