New technology for controlling biofilm formation in water distribution system

The biofilm formation rate was measured in situ in a hot water system in an apartment building by specially designed sampling equipment, and the net growth of the suspended bacteria was measured by incubation of water samples with the indigeneous bacteria. The biofilm formation rate reached a higher level in the hot water distribution system (2.1 d−1 to 2.3 d−1) than in the hot water tank (1.4 d−1 to 2.2 d−1) indicating an important area for surface associated growth. The net growth rate of the suspended bacteria measured in hot water from the top, middle and bottom of the hot water tank, in the sludge, or in the water from the distribution system was negligible. This indicated that bacterial growth took place on the inner surfaces in the hot water system and biofilm formation and detachment of bacteria could account for most of the suspended bacteria actually measured in hot water. Therefore, attempts to reduce the number of bacteria in a hot water system have to include the distribution system as well as the hot water tank.

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In vitro assessment of inter-kingdom biofilm formation by bacteria and filamentous fungi isolated from a drinking water distribution system

Biofouling ◽

10.1080/08927014.2019.1688793 ◽

2019 ◽

Vol 35 (10) ◽

pp. 1041-1054 ◽

Cited By ~ 6

Author(s):

Tiago Barros Afonso ◽

Lúcia Chaves Simões ◽

Nelson Lima

Keyword(s):

Drinking Water ◽

Filamentous Fungi ◽

Distribution System ◽

Biofilm Formation ◽

Water Distribution ◽

Water Distribution System ◽

Drinking Water Distribution System ◽

Drinking Water Distribution ◽

In Vitro Assessment

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Microbial Diversity and their Biofilm Formation Potential in Pipes of Water Distribution System

Asian Journal of Water Environment and Pollution ◽

10.3233/ajw200058 ◽

2020 ◽

Vol 17 (4) ◽

pp. 113-117

Author(s):

Rajanbir Kaur ◽

Rajinder Kaur

Keyword(s):

Drinking Water ◽

Distribution System ◽

Biofilm Formation ◽

Distribution Systems ◽

Water Distribution ◽

Potable Water ◽

Water Distribution System ◽

Water Distribution Systems ◽

Growth Patterns ◽

Water Borne

Microbes are ubiquitous in surface as well as in ground water and some of them can make their way into potable water distribution systems. Contaminated soil with human and animal fecal matter, ill-maintained water and sewage pipelines, poor sanitation and personal hygiene are the main factors responsible for the presence of microbial pathogens in the drinking water. The presence of water-borne microbes in the potable drinking water systems determines its quality. Common microbes present in contaminated water are Shigella, Escherichia coli, Vibrio cholerae, Pseudomonas sp, Salmonella sp etc. The water-borne pathogens that reside and reproduce in water distribution system causes infection of gastrointestinal tract, urinary tract, skin, and lymph nodes. When these pathogens enter into the water distribution system pipelines they form biofilms. The formation of biofilm is a key component in microbial studies. Biofilm is the sessile aggregation of bacterial cells that adhere to each other on living or non-living surfaces and forms extracellular polymeric substances (EPS). The surface physico-chemical properties of both bacteria and substratum were important for the establishment of bacterial adhesion. Bacteria forming biofilms possesses different growth patterns, responds to specific micro-environmental conditions for the formation of structurally complex mature biofilms. In water distribution systems, adhesion of microbes to the water pipelines initiate biofilm formation which in return reduces the quality of potable water and increases the corrosion of pipes.

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Modeling of biofilm in the water distribution system

Water Science & Technology Water Supply ◽

10.2166/ws.2008.094 ◽

2008 ◽

Vol 8 (5) ◽

pp. 513-518

Author(s):

Tai-Lee Hu ◽

Chenfang Lin ◽

Wei-Yu Chen

Keyword(s):

Distribution System ◽

Biofilm Formation ◽

Water Distribution ◽

Water Distribution System ◽

Pipe Wall ◽

Model Simulation ◽

Tap Water ◽

Growth Data ◽

Data Set ◽

Biofilm Growth

In order to understand the growth of biofilm and to serve as the basis of cleaning the water distribution pipeline, this study used a multi-attachment dynamic model to simulate the growth of microorganisms' attachment to the pipe wall. The model had considered attachment, detachment, and propagating factors. The attachment and detachment factors are divided into “cell to cell” and “cell to substratum”. Factors for biofilm growth included two possibilities, which was “lateral growth” and “vertical growth”. Data set of the biofilm biomass from a laboratory scale water distribution system was measured. The data and the model simulation curves were compared so as to justify the performance of the model. The results show that several sets of parameters could be identified. From the simulation of biofilm biomass in the pipeline, the microbial growth related with the incubation time. Due to nutrients being restricted, the biomass of biofilm in the water distribution system did not continue to grow and reached a maximum at about Day 40. From the simulation results, it was suggested the time of cleaning the water distribution pipeline be shortened to one or two months. The model was applied to simulate the tap water biofilm in the pipeline of Kaohsiung city, the second largest in Taiwan with 1.5 million population. The results revealed various levels of risks and the proportionality between the biomass in the water and the growth rate of biofilm. However, most households had the purifying facility of a reverse osmosis system. From the simulation, the facility proved its effectiveness for preventing the intervention of bacteria from the biofilm formation in the distribution pipelines.

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