Influence of hydraulic regimes on bacterial community structure and composition in an experimental drinking water distribution system

Douterelo, Isabel; Sharpe, Rebecca; Boxall, Joby

doi:10.1016/j.watres.2012.09.053

Cited by 250 publications

(204 citation statements)

References 61 publications

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“…Douterelo et al (2013) examined biofilms from drinking water distribution systems and found that the hydraulic regime influenced the bacterial composition and community structure. They also observed that flushing (sudden flow of fluid at high shear stresses inside the system) did not succeed in total biofilm removal but altered the biofilm microbial community.…”

Section: Introductionmentioning

confidence: 99%

The effect of shear stress on the formation and removal of Bacillus cereus biofilms

Lemos

Mergulhão

Melo

et al. 2015

Food and Bioproducts Processing

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A b s t r a c tThe influence of the shear stress (rw) under which biofilms were formed was assessed on their susceptibility to removal when exposed to chemical and mechanical stresses. A rotating cylinder reactor was used to form biofilms, allowing the simulation of rw conditions similar to those found in industrial settings, particularly in areas with low rw like elbows, corners, valves and dead zones. Bacillus cereus was used as a model bacterium for biofilm formation.Biofilms were formed on AISI316 stainless steel cylinders under different rw (estimated at 0.02, 0.12 and 0.17 Pa) for 7 days. Some phenotypic characteristics, including thickness, biomass production, cellular density and extracellular proteins and polysaccharides content were assessed. Biofilm density was found to increase significantly with rw while the thickness decreased. Also, biofilms formed at 0.02 Pa had lowest biomass content, cell density and extracellular polysaccharide content. Those characteristics were not statistically different for the biofilms formed under 0.12 and 0.17 Pa.Ex situ tests were performed by treating the biofilms with the biocide benzyldimethyldodecyl ammonium chloride (BDMDAC), followed by exposure to increasing rw conditions, up to 1.84 Pa (whereas the maximum rw used during growth was 0.17 Pa). The biofilms formed under low rw were more resistant to removal caused by the BDMDAC action alone. Those formed under higher rw were more resistant to the mechanical and the combined chemical and mechanical treatments. The amount of biofilm remaining on the cylinders, after both treatments was statistically similar for biofilms formed under 0.12 and 0.17Pa. The resistance of biofilms to removal by mechanical treatment (alone and combined with BDMDAC) was related to the amount of matrix polysaccharides.However, none of the methods investigated were able to remove all the biofilm from the cylinders. IntroductionThere is a lack of efficient strategies to clean stagnant zones in industrial plants (Brooks and Flint, 2008). Crevices, corners, dead zones, valves or areas where the mixing rate is low are almost inevitable. Stagnation promotes bacterial accumulation, ultimately leading to biofouling (Manuel et al., 2010). Biofouling is a damaging problem, affecting the energetic efficiency of industrial processes, causing corrosion of the surfaces, decreasing product quality and eventually promoting the spread of pathogens and resistant infectious diseases (Costerton et al., 1999;Ludensky, 2003;Srey et al., 2013). In industrial settings, surface disinfection is usually focused on the use of biocides, aiming to inactivate the microorganisms (Cloete et al., 1998;Faille et al., 2013). Since biofilms are complex biological structures adhered to a sur-face, these strategies often fail, as the removal of biomass is neglected. Hence, cleaning the biomass from the surfaces is fundamental for controlling biofilm development (Flemming, 2011).In the biofilm formation process, the hydrodynamic conditions define the transport of the cells, oxyg...

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Section: Introductionmentioning

confidence: 99%

The effect of shear stress on the formation and removal of Bacillus cereus biofilms

Lemos

Mergulhão

Melo

et al. 2015

Food and Bioproducts Processing

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“…Las bacterias fecales constituyen el principal indicador de riesgo patogénico dentro de los estándares microbiológicos para calidad de agua en la gran mayoría de los países (Sammon et al, 2010;Boubetra et al, 2011). Sin embargo, debido a que la presencia de Pseudomonas en el agua potable es un hecho bastante común (Nawrocki et al, 2010;Douterelo et al, 2013), muy recientemente se han sugerido como buenos indicadores de riesgo humano (Douterelo et al, 2016); siendo, además, una actualidad bien real que los nuevos enfoques y avances en procedimientos metodológicos han logrado evidenciar la proliferación de microorganismos, estructurados en comunidades bacterianas y fúngicas, cuya presencia han deteriorado la seguridad del vital líquido tanto en sus reservorios como en las redes de distribución que surten a los usuarios (Douterelo et al, 2016;Oliveira et al, 2016;Stauber et al, 2016).…”

Section: Resultados Y Discusiónunclassified

“…Más recientemente Douterelo et al (2016), reportaron que las fuentes de agua potable constituyen el "semillero" de los microorganismos formadores de biopelículas por sus capacidades de incrementar resistencia a la desinfección (Soniago et al, 2011;Pereira et al, 2013). De esta manera, muchos patógenos logran sobrevivir durante los tratamientos de desinfección de los reservorios de agua desde donde, dependiendo de las condiciones hidráulicas establecidas para el caudal, viajan a través de los sistemas de acueducto y gran parte de ellos pueden llegar hasta los usuarios en niveles que son directamente proporcionales a la velocidad del flujo (Douterelo et al, 2013;Holinger et al, 2014). En tal sentido, se podría indicar que mientras más rápido son transportados los distintos microorganismos dentro de las tuberías de suministro, se acorta su tiempo de estadía dentro de las mismas y, en consecuencia, también su posibilidad de formar biopelículas.…”

Section: Resultados Y Discusiónunclassified

Diagnóstico del agua utilizada en las procesadoras de café del Municipio Caripe – Estado Monagas, Venezuela.// Diagnosis of the water used in coffee processors of the Caripe Municipality - Monagas State, Venezuela

Acuña

Acuña²,

Martı́nez³

et al. 2017

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ResumenLatinoamérica es la región de mayor producción de café del mundo y en Venezuela Monagas conforma uno de los estados productores en la zona del Municipio Caripe, el cual se surte de cuenca hidrográfica siendo el río Caripe su principal recurso hídrico. La finalidad del presente trabajo consistió en realizar un primer diagnóstico para la calidad del agua utilizada durante el proceso de beneficiado húmedo del café en las pocas procesadoras que aún operan en el Municipio Caripe, considerando específicamente las ubicadas en las Fincas: "Agropecuaria Cantarrana", "Gualberto", "Cocollar", "Lisieux" y "Las Acacias"; a manera de determinar si los parámetros evaluados cumplen con los valores permitidos para la Legislación Venezolana vigente. En base a los resultados obtenidos, en general se observó que todos los parámetros evaluados cumplen con los límites permitidos en cuanto a su calidad, a excepción del análisis microbiológico relacionado con los niveles de coliformes totales cumplido sólo para la beneficiadora "Cantarrana"; mientras que las demás productoras incumplen con este parámetro de calidad siendo bastante evidente en el caso de la procesadora "Cocollar", cuya agua presentó los más altos niveles para estos patógenos (240 para el índice de Número Más Probable/100 mL), que son indicativos de contaminación microbiológica.Palabras Clave: Recurso hídrico, calidad de agua, beneficiado del café, Municipio Caripe. AbstractLatin America is the region with the highest coffee production in the world, and Monagas is one of the producing states in the area of the Caripe Municipality, Venezuela, which is supplied with a hydrographic basin, being the Caripe River its main water resource. The purpose of this study was to conduct a preliminary assessment to the quality of water used during the wet coffee processing in the few processors thet still operating in the Caripe Municipality. It was considered specifically those located in "Agropecuaria Cantarrana", "Gualberto", "Cocollar", "Lisieux", and "Las Acacias" farms, in order to determine whether the evaluated parameters meet the allowed values for the current Venezuelan Legislation. Based on the results obtained, in general it was observed that all parameters evaluated comply with the permitted limits in terms of quality, except for microbiological analysis related to the levels of total coliforms fulfilled only for "Cantarrana" processor. While other producers fail to comply with this quality parameter, being quite evident in the case of the "Cocollar" processor whose water had the highest levels for these pathogens (240 for the Most Probable Number/100 mL index), which are indicative of microbiological contamination.

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“…Polyethylene pipe was selected as it is a prevalent and representative current material used in distribution systems world-wide. In order to provide representative water quality the facility is fitted with a trickle feed (and drain) from the local water distribution system [10].…”

Section: Descriptive Analysismentioning

confidence: 99%

“…Most of biofilm research in DWDSs is based on studying the influence of the hydraulic conditions, the physical characteristics of the distribution system and the physico-chemical characteristics of the circulating water, among others, on biofilm development, besides from the interactions among microorganisms [19]. Although numerous studies have been carried out in relation to the influence that a number of characteristics of the DWDSs have on biofilm development [10,[20][21][22], in most cases, these characteristics are studied individually or in pairs, at most. Distribution systems are the major components of water utilities.…”

Section: Introductionmentioning

confidence: 99%

Assessing biofilm development in drinking water distribution systems by Machine Learning methods

Martínez¹

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Influence of hydraulic regimes on bacterial community structure and composition in an experimental drinking water distribution system

Cited by 250 publications

References 61 publications

The effect of shear stress on the formation and removal of Bacillus cereus biofilms

The effect of shear stress on the formation and removal of Bacillus cereus biofilms

Diagnóstico del agua utilizada en las procesadoras de café del Municipio Caripe – Estado Monagas, Venezuela.// Diagnosis of the water used in coffee processors of the Caripe Municipality - Monagas State, Venezuela

Assessing biofilm development in drinking water distribution systems by Machine Learning methods

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