Characterisation of the behaviour of particles in biofilters for pre-treatment of drinking water
Artikel i vetenskaplig tidskrift, 2005

Biofiltration of surface water was examined using granular activated carbon (GAC) and expanded clay (EC). Particle removal was 60-90%, measured by flow cytometry, which enabled discrimination between total- and autofluorescent particles (microalgae) in size ranges of 0.4-1 and 1-15 mu m, and measured by on-line particle counting. Total particles were removed at a higher degree than autofluorescent particles. The biofilters were also challenged with 1 mu m fluorescent microspheres with hydrophobic and hydrophilic surface characteristics and bacteriophages (Salmonella typhimurium 2813). Added microspheres were removed at 97-99% (hydrophobic) and 85-89% (hydrophilic) after 5 hydraulic residence times (HRT) and microspheres retained in the biofilter media were slowly detaching into the filtrate for a long time after the addition. Removal of bacteriophages (5 HRT) was considerably lower at 40-59%, and no long-lasting detachment was observed. A comparison of experimental data with theoretical predictions for removal of particles in clean granular media filters revealed a similar or higher removal of particles around 1 mu m in size than predicted, while bacteriophages were removed at a similar or lesser extent than predicted. The results highlight the selectivity and dynamic behaviour of the particle removal processes and have implications for operation and microbial risk assessment of a treatment train with biofilters as pre-treatment. (c) 2005 Elsevier Ltd. All rights reserved.

media

biofiltration

cysts

adhesion

filtration

autofluoreseent microalgae

particles

retention

bacteriophages

removal

bacteria

drinking water

pre-treatment

cryptosporidium oocysts

surrogate

efficiency

microspheres

Författare

Frank Persson

Göteborgs universitet

J. Långmark

Swedish Institute for Infectious Disease Control

Gerald Heinicke

Chalmers, Bygg- och miljöteknik, Vatten Miljö Teknik

Torsten Hedberg

Chalmers, Bygg- och miljöteknik, Vatten Miljö Teknik

J. Tobiason

University of Massachusetts

T. A. Stenström

Swedish Institute for Infectious Disease Control

Malte Hermansson

Göteborgs universitet

Water Research

0043-1354 (ISSN)

Vol. 39 16 3791-3800

Ämneskategorier

Biokemi och molekylärbiologi

DOI

10.1016/j.watres.2005.07.007