scholarly journals Aggregation and biofilm formation of bacteria isolated from domestic drinking water

2013 ◽  
Vol 13 (4) ◽  
pp. 1016-1023 ◽  
Author(s):  
B. Ramalingam ◽  
R. Sekar ◽  
J. B. Boxall ◽  
C. A. Biggs
Keyword(s):  
Drinking Water ◽  
Biofilm Formation ◽  
Distribution Systems ◽  
Water Distribution ◽  
Control Strategies ◽  
Extended Period ◽  
Dapi Staining ◽  
Drinking Water Distribution Systems ◽  
Potential Control ◽  
Pure Cultures

The objective of this study was to investigate the autoaggregation, coaggregation and biofilm formation of four bacteria namely Sphingobium, Xenophilus, Methylobacterium and Rhodococcus isolated from drinking water. Auto and coaggregation studies were performed by both qualitative (DAPI staining) and semi-quantitative (visual coaggregation) methods and biofilms produced by either pure or dual-cultures were quantified by crystal violet method. Results from the semi-quantitative visual aggregation method did not show any immediate auto or coaggregation, which was confirmed by the 4′,6 diamidino-2-phenylindole (DAPI) staining method. However, after 2 hours, Methylobacterium showed the highest autoaggregation of all four isolates. The Methylobacterium combinations showed highest coaggregation between dual species at extended period of times (72 hours). Biofilm formation by pure cultures was negligible in comparison to the quantity of biofilm produced by dual-species biofilms. The overall results show that coaggregation of bacteria isolated from drinking water was mediated by species-specific and time-dependent interactions with a synergistic type of biofilm formation. The results of this study are therefore a useful step in assisting the development of potential control strategies by identifying specific bacteria that promote aggregation or biofilm formation in drinking water distribution systems.

scholarly journals Biofilm formation potential and chlorine resistance of typical bacteria isolated from drinking water distribution systems

RSC Advances ◽  
2020 ◽  
Vol 10 (52) ◽  
pp. 31295-31304 ◽  
Author(s):  
Zebing Zhu ◽  
Lili Shan ◽  
Fengping Hu ◽  
Zehua Li ◽  
Dan Zhong ◽  
...  
Keyword(s):  
Drinking Water ◽  
Microbial Communities ◽  
Biofilm Formation ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Formation Potential ◽  
Drinking Water Distribution Systems ◽  
Drinking Water Distribution ◽  
Safety Of Drinking Water

Biofilms are the main carrier of microbial communities throughout drinking water distribution systems (DWDSs), and strongly affect the safety of drinking water.

scholarly journals Quantification of the bacterial community of drinking water-associated biofilms under different flow velocities and changing chlorination regimes

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Z. Tsvetanova
Keyword(s):  
Drinking Water ◽  
Flow Velocity ◽  
Biofilm Formation ◽  
Distribution Systems ◽  
Water Distribution ◽  
Culturable Bacteria ◽  
Drinking Water Distribution Systems ◽  
Biomass Removal ◽  
Water Chlorination ◽  
Flow Velocities

Abstract Microbial growth in drinking water distribution systems (DWDS) depends on a great number of factors, and its control represents a great challenge for management of these engineering systems. The present case study assessed the influence that a pair of factors—water chlorination and flow velocity—had on the biofilms formed in a model DWDS in 626 days. The culturable bacteria number and biomass of the biofilms developed under the flow velocities of 0.3 m/s, 0.5 m/s, 0.7 m/s and 1 m/s were determined during three consecutively applied regimes of water chlorination to 0.05 mg/l (in 380 days), 0.42 mg/l (in 46 days) and 0.14 mg/l free chlorine (in 200 days). The results demonstrated that biofilm formation was a prolonged process directly depended on flow velocity at drinking water chlorination to 0.05 mg/l. The increase in the water chlorination to 0.42 mg/l chlorine resulted in both the reduction in culturable bacteria number and biomass removal, but the bacteria killing and the biofilm removal were distinct processes. The biocide action of chlorine was faster and more effective than its biomass removal effect. The chlorine decreasing from 0.42 to 0.14 mg/l resulted in increasing the biofilm HPC densities, although the biomass removal process was still continuing. The study carried out contributes for better understanding the biofilm behavior in DWDS and demonstrates that biofilm formation could be managed within a DWDS through operational decisions on parameters that can be changed and controlled as flow velocity and chlorination to safeguard drinking water quality.

Kinetic aspects of biofilm formation on surfaces exposed to drinking water

1995 ◽  
Vol 32 (8) ◽  
pp. 61-65 ◽  
Author(s):  
D. van der Kooij ◽  
H. S. Vrouwenvelder ◽  
H. R. Veenendaal
Keyword(s):  
Drinking Water ◽  
Biofilm Formation ◽  
Distribution Systems ◽  
Water Distribution ◽  
Formation Rate ◽  
Water Distribution Systems ◽  
Acetate Concentration ◽  
Drinking Water Distribution Systems ◽  
Drinking Water Distribution ◽  
The Relationship

Biofilm formation in drinking water distribution systems should be limited to prevent the multiplication of undesirable bacteria and other organisms. Certain types of drinking water with an AOC concentration below 10 μg of acetate-C eq/l can support the growth of Aeromonas. Therefore, the effect of acetate at a concentration of 10 μg of C/l on the biofilm formation rate (BFR) of drinking water with a low AOC concentration (3.2 μg C/l) was determined. Drinking water without acetate had a BFR of 3.9 pg ATP/cm2.day, whereas a BFR value of 362 pg ATP/cm2.day was found with acetate added. These data indicate that a low acetate concentration strongly affects biofilm formation, and that only a small fraction of AOC is available for biofilm formation. Aeromonads did not multiply in the biofilm despite their ability to grow at a concentration of 10 μg of acetate-C/l. Further investigations are needed to elucidate the relationship between substrate concentration and biofilm formation in drinking water distribution systems and the growth of undesirable bacteria in these biofilms.

Amoebae-resisting bacteria in drinking water: risk assessment and management

2008 ◽  
Vol 58 (3) ◽  
pp. 571-577 ◽  
Author(s):  
J. F. Loret ◽  
M. Jousset ◽  
S. Robert ◽  
G. Saucedo ◽  
F. Ribas ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Drinking Water ◽  
Distribution Systems ◽  
Water Distribution ◽  
Control Strategies ◽  
Water Production ◽  
Water Safety ◽  
Drinking Water Distribution Systems ◽  
Drinking Water Distribution ◽  
Drinking Water Production

Free-living amoebae have been detected in a large number of man-made water systems, including drinking water distribution systems. Some of these amoebae can host amoebae-resisting bacteria, and thus act potentially as reservoirs and vehicles for a number of pathogens. The objectives of this study were to characterize the amoebae and amoebae-resisting bacteria present in different raw waters used for drinking water production, and to assess the efficiency of different treatments applied for drinking water production in removing or inactivating these amoebae. The preliminary results of this study confirm the presence of amoebae and amoebae-resisting bacteria in raw waters used for drinking water production. Due to their capacity to encyst, most of these amoebae are extremely resistant to disinfection processes. In these conditions, preventing the dissemination of these micro-organisms through drinking water will mainly require their physical removal by clarification and filtration processes. The particular hazard that amoebae-resisting bacteria represent in drinking water production should be taken into account in any risk assessment conducted in the framework of a water safety plan, and control strategies based on physical removal rather than disinfection should be adopted where necessary.

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