The present kinetic study develops a model describing zero-order soluble substrate (methanol) diffusion and biochemical reaction inside the porous biofilm matrix with simultaneous particle removal by bioflocculation at the surface of aerobic biological films. Methanol (CH3OH) served as the dissolved substrate and native corn starch served as the organic particulates; 95% of the particles were less than a 23.9-micron equivalent spherical diameter, the median particle diameter was 14.1 microns, and only 5% of the particles were less than 1.4 microns. A bench-scale completely mixed rotating disc biofilm reactor was used to grow and experimentally measure substrate removal, both dissolved and particulate, as a function of the ratio of external biofilm area to bulk liquid volumetric flow rate, A/Q. A curve-fitting routine revealed that within the range of concentrations used in this research, internal diffusion and consumption of methanol was predicted by a zero-order reaction, and the removal of organic particulates was described by a first-order bioflocculation kinetic expression. A significant effect of the influent concentration of methanol and corn starch on the numerical value of the kinetic constants could be observed.
ASJC Scopus subject areas
- Environmental Chemistry
- Waste Management and Disposal