High rates of microbial sulphate reduction in a mesophilic ethanol-fed expanded-granular-sludge-blanket reactor

De Smul, A.; Dries, J.; Goethals, L.; Grootaerd, H.; Verstraete, W.

doi:10.1007/S002530051053

Title

High rates of microbial sulphate reduction in a mesophilic ethanol-fed expanded-granular-sludge-blanket reactor

Author

De Smul, A.

Dries, J.

Goethals, L.

Grootaerd, H.

Verstraete, W.

Abstract

In a mesophilic (30-35 degrees C), sulphidogenic, ethanol-fed expanded-granular-sludge-blanket reactor, sulphate, at loading rates of up to 10.0-12.0 g Sl(-1) day(-1) was removed with an average efficiency of more than 80%. The pH was between 7.7 and 8.3 and the maximal total dissolved sulphide concentration was up to 20 mM S (650 mg S/l). The alkaline pH was maintained by either a pH-control unit with sodium hydroxide or by stripping part of the sulphide and CO2 from the recycle with nitrogen gas. The superficial upstream liquid velocity (v(up)) was 3.0-4.5 m/h. The ratio of ethanol to sulphur was near stoichiometry. At alkaline pH, the activity of the acetotrophic sulphate-reducing bacteria, growing on acetate, was strongly enhanced, whereas at pH below 7.7 the acetotrophic sulphate-reducing bacteria were inhibited by aqueous H2S. With regard to the removal efficiency and operational stability, external stripping with N-2 and pH control were equally successful.

Language

English

Source (journal)

Applied microbiology and biotechnology. - Berlin, 1984, currens

Publication

Berlin : 1997

ISSN

0175-7598 [print]

1432-0614 [online]

DOI

10.1007/S002530051053

Volume/pages