Impact of temperature on nitrification in biological activated carbon (BAC) filters used for drinking water treatment

2001 ◽  
Vol 35 (12) ◽  
pp. 2923-2934 ◽  
Author(s):  
Anneli Andersson ◽  
Patrick Laurent ◽  
Anne Kihn ◽  
Michèle Prévost ◽  
Pierre Servais
Author(s):  
Nguyet Thi-Minh Dao ◽  
The-Anh Nguyen ◽  
Viet-Anh Nguyen ◽  
Mitsuharu Terashima ◽  
Hidenari Yasui

The occurrence of pesticides even at low concentrations in drinking water sources might induce potential risks to public health. This study aimed to investigate the removal mechanisms of eight pesticides by the nitrifying expanded-bed filter using biological activated carbon media at the pretreatment of a drinking water plant. The field analysis demonstrated that four pesticides Flutolanil, Buprofezin, Chlorpyrifos, and Fenobucard, were removed at 82%, 55%, 54%, and 52% respectively, while others were not significantly removed. Under controlled laboratory conditions with continuous and batch experiments, the adsorption onto the biological activated carbon media was demonstrated to be the main removal pathway of the pesticides. The contribution of microorganisms to the pesticide removals was rather limited. The pesticide removals observed in the field reactor was speculated to be the adsorption on the suspended solids presented in the influent water. The obtained results highlighted the need to apply a more efficient and cost-effective technology to remove the pesticide in the drinking water treatment process. Keywords: biological activated carbon; drinking water treatment; nitrifying expanded-bed filter; pesticide removal.


2007 ◽  
Vol 55 (8-9) ◽  
pp. 173-180 ◽  
Author(s):  
I. Kasuga ◽  
D. Shimazaki ◽  
S. Kunikane

The influence of backwashing on the biofilm community developed on biological activated carbon (BAC) used in a drinking water treatment plant was investigated by means of bacterial cell enumeration and terminal-restriction fragment length polymorphism (T-RFLP) fingerprinting analysis of bacterial and eukaryotic ribosomal RNA genes (rDNA). After backwashing, the attached bacterial abundance in the top layer of the BAC bed decreased to 64% of that before backwashing. The community level changes caused by backwashing were examined through the T-RFLP profiles. In the bacterial 16S rDNA analysis, the relative abundances of some terminal-restriction fragments (T-RFs) including the Planctomycetes-derived fragment increased; however, the relative abundances of some T-RFs including the Betaproteobacteria-derived fragments decreased. In the eukaryotic 18S rDNA analysis, the relative abundances of some T-RFs including the protozoan Cercozoa-derived fragments increased; however, the relative abundances of some T-RFs including the metazoan Chaetonotus- and Paratripyla-derived fragments decreased. The T-RFLP analysis suggests that backwashing can cause changes in the relative compositions of microorganisms in a BAC biofilm in the top layer of the bed.


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