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Kinetics of Microbial By‐Product Formation in Chemostat Pure Cultures

1988; American Society of Civil Engineers; Volume: 114; Issue: 5 Linguagem: Inglês

10.1061/(asce)0733-9372(1988)114

1943-7870

Oliver J. Hao, Antonio O. Lau,

3D Printing in Biomedical Research

Microbial by‐products are present in large quantities in both activated sludge (AS) systems and chemostat pure cultures. In wastewater AS systems, these by‐products impose additional organic loads on downstream processes. These by‐products are primary contributors to the dependence between effluent and influent substrate concentrations. Also, their presence in AS systems is partially responsible for producing the same effluent quality by either completely mixed AS or plug flow system. The specific rate of product formation (v) was investigated using chemostat pure cultures of Sphaerotilus species, S. natans, and Pseudomonas species. The results clearly indicate that v is an exponential function of the dilution rate (D). When D approaches zero, large quantities of microbial products are possibly caused by cell maintenance and/or endogenous respiration. As D increases, the concentration of products decreases to a minimum level. Further increases in D result in significant increases in the concentration of microbial by‐products. Also, both the by‐product concentrations and the v are reduced under nitrogen limiting or low dissolved oxygen conditions for the two obligate aerobic Sphaerotilus species. At low dissolved oxygen concentrations, the microbial by‐products for facultative anaerobic Pseudomonas species increase significantly.