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Monitoring of the Biological Nutrient Removal Process by an On‐Line NAD(P)H Fluorometer
Author(s) -
Ju Lu Kwang,
Lee Jaw F.,
Armiger William B.
Publication year - 1995
Publication title -
biotechnology progress
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 129
eISSN - 1520-6033
pISSN - 8756-7938
DOI - 10.1021/bp00035a008
Subject(s) - fluorometer , nad+ kinase , nutrient , chemistry , process (computing) , environmental chemistry , environmental science , chromatography , biochemistry , computer science , organic chemistry , enzyme , physics , operating system , quantum mechanics , fluorescence
An on‐line NAD(P)H fluorometer has been used to investigate the fluorescence profile of a simulated anaerobic/anoxic/oxic biological nutrient removal (BNR) process and its dependency on operating parameters, such as the concentrations of organic substrate (acetate) and activated sludge. As expected from the different rates of NAD‐(P)H oxidation at different stages, the order of fluorescence levels was found to be anaerobic > anoxic > oxic. The effects of the acetate and sludge concentrations were observed most clearly at the anoxic stage: an increase in either concentration led to faster recovery of fluorescence from the drop caused by NO 3 − addition. A higher acetate concentration also resulted in a more significant, continuous rise in fluorescence, corresponding well with the enhanced PO 4 3− release, at the anaerobic stage and a slower initial fluorescence decrease at the oxic stage, indicating the dependency of the decrease on substrate availability. The ratio of the two fluorescence drops caused by NO 3 − addition and aeration, Δ 1 /Δ 2 , obtained with the plant's sludge was found to be 0.7 × 0.1, which is similar to those of pure nitrate‐respiring cultures (e.g., Pseudomonas aeruginosa and Escherichia coli) . The dominant majority of nonnitrifiers in the sludge therefore are capable of nitrate respiration, and the nitrifiers either contribute little to the overall fluorescence or perform nitrate respiration as the rest of the sludge population.