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Biologischer Abbau von 2,4-Dinitrotoluol in einer kontinuierlich betriebenen Versuchanlage und kinetische Untersuchungen

Biological degradation of 2,4-Dinitrotoluene in a continous bioreactor and kinetic studies
: Heinze, L.; Brosius, M.; Wiesmann, U.


Acta Hydrochimica et Hydrobiologica 23 (1995), Nr.6, S.254-263
ISSN: 0323-4320
ISSN: 1863-0669
ISSN: 1521-401X
Fraunhofer IITB, Außenstelle Prozessoptimierung (EPO); 1997
2,4-Dinitrotoluene; 2,4-Dinitrotoluol; Abwasserbehandlung; aerober Abbau; aerobic degradation; element mass balance; Elementbilanzen; kinetics; Kinetik; Mineralisierung; mineralization; wastewater treatment

Experimental results on the aerobic biological degradation with complete mineralization of 2,4-dinitrotoluene (2,4 DNT) are presented. A culture of Pseudomonas sp. DNT from Spain and Nishino was used. The degradation was examined with batch cultures for the determination of kinetic and stoichiometric coefficients. Further experiments were carried out with a continuous culture in a fixed-bed reactor with reciculation in order to obtain high degradation rates. The reactor was packed with ceramic Raschig rings (55 mL) and had a liquid reaction volume of 160 mL. The minimal salt media from Spanggord et al. with and without (HH4)2SO4 as nitrogen source was used as substrate. 2,4-DNT was the sole source of carbon and energy. From batch experiments a yield coefficient Y(sub)B/S = (0.30 +- 0.05)g g(exp)-1 was calculated from a mass balance of the elements. This result was confirmed by calculations using literature data. Fitting the experimental data to the Monod equation my(sub)max = 0.1 h(exp )-1 and K(sub)S = 0.01 ... 0.03 mmol L(exp)-1 were obtained. It was demonstrated by batch experiments that 2,4-DNT is not only used as the source of carbon and energy but also as the nitrogen source. In the fixed-bed reactor a degradation of 92 ... 97% was reached with a maximal 2,4-DNT load of 95 mg L(exp)-1 h(exp)-1. The rate of continuous degradation could be described by a pseudo-first-order reaction (k = 9.73 h(exp)-1). The complete mineralization of 2,4-DNT was verified by the measurement of DOC and the formed nitrite and nitrate. The formed nitrite was nitrified simultaneously. It was demonstrated by these experiments that large scale bioogical treatment of industrial effluent containing 2,4-DNT may be successful.