Removal of geosmin and MIB by biofiltration - An investigation discriminating between adsorption and biodegradation
Artikel i vetenskaplig tidskrift, 2007

Geosmin and 2-methylisoborneol (MIB) are two substances causing earthy/musty odours that are difficult to remove by conventional chemical drinking water treatment. In this study removal of geosmin and MIB by biofiltration of untreated surface water was investigated using granular activated carbon (GAC) and crushed expanded clay (EC) as filter media. Biofiltration through both GAC and EC removed geosmin and MIB present at low (20 ng l(-1)) concentrations by at least 97% at an empty bed contact time of 30 minutes and a temperature of 15 degrees C. At lower temperature (6-12 degrees C) and simultaneously lower biomass concentrations, removal efficiency was similar in the GAC but considerably lower in the EC biofilter, pointing to a second mechanism different from biodegradation. Consequently, microbial activity was suppressed with azide to enable discrimination between biodegradation and adsorption. During azide dosage, the GAC biofilters still removed geosmin and MIB nearly unaffectedly. In the EC biofilter, however, removal of both odorants ceased completely. Methylene blue adsorption confirmed that the GAC, even after almost four years of operation receiving surface water, had capacity to remove geosmin and MlB by adsorption. Since odour episodes commonly occur during the warm season when microbiological activity is high, EC constitutes a viable option as carrier medium for direct biological filtration of surface water. The additional GAC adsorption capacity however adds robustness to the removal process.

MIB

drinking water

biodegradation

geosmin

SURFACE-WATER TREATMENT

SAND FILTRATION

DRINKING-WATER

COMPOUNDS

BIOLOGICAL FILTER

MUSTY ODOR

TASTE

adsorption

biofiltration

ACTIVATED CARBON ADSORPTION

OFF-FLAVOR COMPOUNDS

2-METHYLISOBORNEOL

MICROBIAL BIOMASS

Författare

Frank Persson

Göteborgs universitet

Gerald Heinicke

Chalmers, Bygg- och miljöteknik

T. Hedberg

Malte Hermansson

Göteborgs universitet

W. Uhl

Environmental Technology (United Kingdom)

0959-3330 (ISSN)

Vol. 28 95-104

Ämneskategorier

Biologiska vetenskaper

PubMed

17283953