A new pH-based procedure to model toxic effects on nitrifiers in activated sludge
✍ Scribed by Krist Gernaey; Davide Maffei; Peter Vanrolleghem; Willy Verstraete
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1999
- Tongue
- English
- Weight
- 157 KB
- Volume
- 74
- Category
- Article
- ISSN
- 0268-2575
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✦ Synopsis
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 af®nity constant (K NH ) of NH 4 -oxidizing bacteria in activated sludge samples. Experiments in the presence of increasing concentrations of a toxic compound (CN À , 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 suf®cient 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 nitri®cation inhibition by phenol and degradation of the phenol by heterotrophic bacteria.