Characterisation of the behaviour of particles in biofilters for pre-treatment of drinking water
Journal article, 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

Author

Frank Persson

University of Gothenburg

J. Långmark

Swedish Institute for Infectious Disease Control

Gerald Heinicke

Chalmers, Civil and Environmental Engineering, Water Environment Technology

Torsten Hedberg

Chalmers, Civil and Environmental Engineering, Water Environment Technology

J. Tobiason

University of Massachusetts

T. A. Stenström

Swedish Institute for Infectious Disease Control

Malte Hermansson

University of Gothenburg

Water Research

0043-1354 (ISSN)

Vol. 39 16 3791-3800

Subject Categories

Biochemistry and Molecular Biology

DOI

10.1016/j.watres.2005.07.007

More information

Created

10/7/2017