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A new pH‐based procedure to model toxic effects on nitrifiers in activated sludge
Author(s) -
Gernaey Krist,
Maffei Davide,
Vanrolleghem Peter,
Verstraete Willy
Publication year - 1999
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/(sici)1097-4660(199907)74:7<679::aid-jctb90>3.0.co;2-k
Subject(s) - activated sludge , phenol , chemistry , titration , nitrification , nitrifying bacteria , oxidizing agent , substrate (aquarium) , chromatography , bacteria , wastewater , environmental chemistry , pulp and paper industry , environmental engineering , inorganic chemistry , organic chemistry , environmental science , biology , ecology , nitrogen , engineering , genetics
A combination of a titration experiment and a biokinetic parameter estimation procedure is proposed as an experimental tool to study the kinetics of NH 4 + ‐oxidizing bacteria in activated sludge. The method was used to quantify the effect of low concentrations of a toxic compound on the maximum substrate removal capacity and the substrate affinity constant (K NH ) of NH 4 + ‐oxidizing bacteria in activated sludge samples. Experiments in the presence of increasing concentrations of a toxic compound (CN − , 3,5‐DCP, Cu 2+ and phenol) were performed with nitrifying activated sludge samples obtained from two full‐scale wastewater treatment plants. The repeatability of the proposed procedure was found to be sufficient to deduce trends in the behavior of the NH 4 + ‐N‐oxidizing bacteria based on one series of experiments with increasing toxicant concentrations. The experimental results showed that the two sludge samples reacted completely differently in the presence of a certain concentration of the same toxic compound. For phenol, the shape of the titration curves did not correspond any longer to a simple Monod model. In this case, titration curves could be described by a model including both nitrification inhibition by phenol and degradation of the phenol by heterotrophic bacteria. © 1999 Society of Chemical Industry