The occurrence of microorganisms in water main encrustations

Allen, Martin; Taylor, Raymond H.; Geldreich, Edwin E.

doi:10.1002/j.1551-8833.1980.tb04598.x

Cited by 82 publications

(34 citation statements)

References 2 publications

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“…The ultrastructural features of the surface matrixes were very similar to those reported for other municipal distribution systems (1,8,14,18). Moreover, the occurrence of bacteria within surface encrustations of Springfield's biofilms is consistent with prior findings (1,9,13,19). Unique to the present study is the presence of fungal spores as a major component of surface biofilms and encrustations.…”

supporting

confidence: 86%

Characterization of Fungal Biofilms within a Municipal Water Distribution System

2000

Appl Environ Microbiol

139

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Biofilms of a municipal water distribution system were characterized to assess the occurrence of fungi within surface matrixes. Densities of filamentous fungi ranged from 4.0 to 25.2 CFU cm ؊2 , whereas yeast densities ranged from 0 to 8.9 CFU cm ؊2 . Observations by scanning electron microscopy further suggested that spores, not hyphae or vegetative cells, comprised the primary source of viable propagules.The presence of fungi in drinking water and within biofilms of distribution systems has received limited attention. This is due, in part, to the fact that causal relationships between fungal occurrence and water quality remain uncertain. Nonetheless, waterborne fungi are likely associated with taste and odor problems, contamination in food and beverage preparation, and a variety of health-related effects (3,5,10,17). Uncertain ramifications of fungi in potable water have led to a limited number of investigations which show that fungi are present in a significant proportion of tap water samples; however, species abundance and diversity are extremely variable (6,11,13,16). This variation is often attributed to factors such as raw water source, water temperature patterns, treatment conditions, and maintenance of distribution systems (5). The nature and extent of fungi within distribution biofilms remain more obscure; only a single report has demonstrated conclusively that fungi are an integral biofilm component (12). Although it is assumed that contamination is attributable to spore deposition within the biofilm matrix, there is limited evidence to support this premise.Pipe surfaces were collected from the Springfield, Mo., water distribution system from March to July 1997. This municipal system serves approximately 100,000 people and consists of over 900 miles of water mains. Physical and chemical characteristics of this distribution system from January to July 1997 are reported in Table 1. Each sample consisted of a single pipe coupon (i.e., a longitudinal section of the inner pipe surface) obtained during routine maintenance and extension of 30-in. mains. During collection, each coupon was carefully rinsed with 2 liters of sterile distilled water and then placed in a sterile plastic bag. Coupons were immediately transported to the laboratory and rinsed again with 1 liter of sterile distilled water. The purpose of each rinse was to minimize the likelihood of contamination by airborne spores. Although each rinse was discarded, preliminary investigations of polyvinyl chloride (PVC) and iron coupons indicated that rinses did not remove biofilm deposition.Small biofilm fragments, each consisting of 0.5 cm 2 of surface matrix, were removed and plated on the following nonselective media: potato dextrose agar (Difco), Czapek solution agar (Difco), cornmeal agar (Difco), Sabouraud dextrose agar (Difco), and YMPG (10 g of dextrose, 5 g of neopeptone, 3 g of yeast extract, 3 g of malt extract, 10 g of agar, 1 liter distilled water). Four replicates of each medium were employed for each coupon to yield a total of 100 frag...

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supporting

confidence: 86%

Characterization of Fungal Biofilms within a Municipal Water Distribution System

2000

Appl Environ Microbiol

139

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“…Diatoms have been observed in waters from urban distribution networks (Allen et al, 1980), and other algae and cyanobacteria have been also reported (Ribas & Oliver, 1970). Some odours and tastes in drinking water have been associated with the presence of algae as well as actinomycetes and yeasts (Bower & Crowe 1988;Lee et al, 1980;Rizet et al, 1984).…”

Section: Introductionmentioning

confidence: 94%

“…However, these treatments may not prevent heterotrophic bacteria occurring in drinking water (van der Kooij, 1977), and it is possible that this could also be the case with algae. Evidence is available to show the development of biofilms containing algae and bacteria on most pipe surfaces (Allen et al, 1980;Le Chevallier et al, 1987). This biofilm might serve as an inoculum for microorganisms in tap waters.…”

Section: Introductionmentioning

confidence: 97%

Algae in urban drinking waters in N.E. Spain

Sabater

1995

J Appl Phycol

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Tap waters from Barcelona and several other locations in N.E. Spain were analyzed to determine the algal occurrence and to assess their probable origin and fate. In general, a low number of taxa (2-9) occurred per sample, while cell density was highly variable (from 20 to more than 1000 cells ml-'). Green algae were usually the most abundant, most of the taxa being common in natural phytoplankton assemblages from mesotrophic or eutrophic waters. The proportion of planktonic to benthic taxa differed between samples, there being only one sample (Lrida) with a predominant planktonic composition. Analysis of treated water revealed that algae were not completely removed at the end of the treatment, meaning that a low number could reach the distribution network. Moreover, other organisms (flagellates) had their origin in storage water tanks. No seasonal pattern of occurrence was apparent since there were many occasional taxa, implying a lack of direct connection between natural populations and tap water algae. It is therefore suggested that algae can reach the distribution network by several possible origins. Algae were sometimes viable; culture experiments showed occasional growth in June, but not in August samples.

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“…On the other hand, such tubercles or nodes do not necessarily reflect an inadequate water or disinfectant treatment, but the result of a constant adaptation of bacterial populations to environmental changes [3,4].…”

Section: Introductionmentioning

confidence: 99%

Adherence of Desulfovibrio Desulfuricans and Bacillus Megaterium on Copper Deoxidized in Phosphorus (Dhp)

Zumelzu¹,

SCHÖBITZ²,

Cabezas³

et al. 2005

Canadian Metallurgical Quarterly

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The study of bacterial adherence was carried out on two types of DHP copper coupons: a) without any surface protection layer and b) with a selenium coating obtained by chemical deposition, the application of selenium as a protection barrier prevents bacteria from the contact with the copper surface and the copper from corrosion, mainly MIC. Trials were performed by means of an experimental device especially designed to simulate the operation conditions found in heater waters. The characterization of bacterial adherence, biofilm formation and microstructural changes of coupons were assessed by bacterial count, fluorescence microscopy and scanning electron microscopy (SEM). The results obtained showed an significant decrease in bacterial population, with low adherence on copper coupons when using heater water. On the contrary, enriching this water with a minimum of nutrients caused an increase in bacterial population and greater adherence of both strains and biofilm development.Résumé -On a effectué l'étude d'adhérence bactérienne sur deux types de coupons de cuivres DHP: a) sans couche de protection de surface et b) avec un revêtement de sélénium obtenu par dépôt chimique. L'application du sélénium comme barrière de protection empêche les bactéries de contacter la surface du cuivre et donc empêche la corrosion du cuivre, principalement par MIC. On a effectué les essais au moyen d'un dispositif expérimental conçu spécialement pour simuler les conditions de fonctionnement des chauffe-eau. On a évalué l'adhérence bactérienne, la formation de film biologique et les changements microstructuraux des coupons par le décompte bactérien, par microscopie par fluorescence et par microscopie électronique à balayage. Les résultats obtenus ont montré une diminution importante de la population bactérienne, avec une faible adhérence sur les coupons de cuivre lorsque l'on utilisait l'eau du chauffe-eau. Au contraire, l'enrichissement de cette eau avec un minimum d'éléments nutritifs a résulté en une augmentation de la population bactérienne et en une plus grande adhérence des deux souches et dans le développement d'un film biologique.

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The occurrence of microorganisms in water main encrustations

Cited by 82 publications

References 2 publications

Characterization of Fungal Biofilms within a Municipal Water Distribution System

Characterization of Fungal Biofilms within a Municipal Water Distribution System

Algae in urban drinking waters in N.E. Spain

Adherence of Desulfovibrio Desulfuricans and Bacillus Megaterium on Copper Deoxidized in Phosphorus (Dhp)

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