The limitations of hydrodynamic removal of biofilms from the dead-ends in a model drinking water distribution system

Simunič, Urh; Pipp, Peter; Dular, Matevž; Stopar, David

doi:10.1016/j.watres.2020.115838

Cited by 17 publications

(9 citation statements)

References 44 publications

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“…The low shear stress allows the initial deposition and consequent fouling formation [193]. In fact, Simunic et al [44] verified that in dead-end zones, fouling was not affected by fluid flushing (high turbulence from high fluid velocity) that was typical for the main pipe. Several studies identified critical areas for fouling formation such as the regions closed to corners and baffles [59,75,104] and header section [102] in HE, regions closed to expansions/contractions [110,120], angles [128,134], elbows [112,133], and valves [12,114] in distribution networks, and regions closed to corners in the bottom [154], and baffles in the tank wall [165] in STRs.…”

Section: Hydrodynamics On (Bio)fouling Prevention and Controlmentioning

confidence: 99%

“…Finally, biofouling also occurs in drinking water distribution systems [26,44,45]. Biofouling is responsible for compromising water quality (affecting taste, odour and colour), and cause pipe corrosion and discolouration [46].…”

Section: (Bio)fouling In Industrial Processesmentioning

confidence: 99%

“…However, under controlled industrial mimicking conditions, it is realistic to interpolate tangible facts that may influence biofouling development in industrial settings. Therefore, commonly used devices for biofouling studies are the flow cell [11,44,194], rotating disk reactor [195,196], rotating cylinder reactor [197,198], and microtiter plates [199,200]. Many other devices have been used for biofouling studies as already reviewed by Gomes et al [26].…”

Section: Hydrodynamics On (Bio)fouling Prevention and Controlmentioning

confidence: 99%

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Overview on the hydrodynamic conditions found in industrial systems and its impact in (bio)fouling formation

Fernandes

Gomes

Simões

et al. 2021

Chemical Engineering Journal

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Biofouling is the unwanted accumulation of deposits on surfaces, composed by organic and inorganic particles and (micro)organisms. Its occurrence in industrial equipment is responsible for several drawbacks related to operation and maintenance costs, reduction of process safety and product quality, and putative outbreaks of pathogens. The understanding on the role of operating conditions in biofouling development highlights the hydrodynamic conditions as key parameter. In general, (bio)fouling occurs in a higher extension when laminar flow conditions are used. However, the characteristics and resilience of biofouling are highly dependent on the hydrodynamic conditions under which it is developed, with turbulent conditions being associated to recalcitrant biodeposits. In industrial settings like heat exchangers, fluid distribution networks and stirred tanks, hydrodynamics plays a dual function, affecting the process effectiveness while favouring biofouling formation. This review summarizes the hydrodynamics played in conventional industrial settings and provides an overview on the relevance of hydrodynamic conditions in biofouling development as well as in the effectiveness of industrial processes.

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Section: Hydrodynamics On (Bio)fouling Prevention and Controlmentioning

confidence: 99%

Section: (Bio)fouling In Industrial Processesmentioning

confidence: 99%

Section: Hydrodynamics On (Bio)fouling Prevention and Controlmentioning

confidence: 99%

See 1 more Smart Citation

Overview on the hydrodynamic conditions found in industrial systems and its impact in (bio)fouling formation

Fernandes

Gomes

Simões

et al. 2021

Chemical Engineering Journal

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“…Biologically unstable water provides perfect conditions for the formation of biofilm, i.e. the colonisation of the surfaces of pipelines by microorganisms, and accumulation of their metabolic products (Asghari et al 2018;Simunič et al 2020). Mature biofilm, also called biological membrane, is a complex structure comparable to an ecosystem (Di Pippo et al 2018), generating strategies of survival in unfavourable environmental conditions (Ahamed et al 2020;Gloag et al 2020).…”

Section: Introductionmentioning

confidence: 99%

Detection of Biofilm on Water Supply Technical Materials with the Application of an Impedance Sensor

2022

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In favourable environmental conditions microorganisms can adhere to surfaces and reproduce, forming biofilm. Such a structure causes biodeterioration, i.e. biological degradation of technical materials. The issue is of high importance in the case of distribution of treated water to end-point consumers. An important factor determining the formation of biofilm is the type and character of the surface which can stimulate or inhibit its growth. The article presents innovative results of research involving measurement of growth of biofilm on technical materials used for the construction of water supply networks by means of an impedance sensor. The research was conducted at a laboratory scale continuously for 6 months, reflecting actual conditions occurring in water distribution systems. After half a year culture of environmental microorganisms in the bioreactor, an almost 100% increase in the value of relative impedance was recorded by means of a sensor placed inside the bioreactor. A comparison of the surface coverage of technical materials and the sensor with bacteria (fluorescence in situ hybridization) showed that the sensor could be used for technical materials made of polybutylene, polypropylene, and polyvinyl chloride. Observations (scanning electron microscopy) of the surface of the plastics used to build the water supply network pipes (new materials, with biofilm present, and after detaching the biofilm) showed significant changes in the structures of the materials due to biofilm formation. The largest changes in the structure were observed on the polyethylene and polypropylene surfaces. The proposed sensor could be applied in the measurements of biofilm adhesion to selected technical materials.

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“…These biofilms are found to release 58% of the bacteria in the distributed water [6]. Simple hydrodynamic means to prevent biofilms' growth, such as using fast flowing water, have been found ineffective [7] as biofilms can withstand high shear stresses especially in dead-ends. Traditional cleaning agents are also known to be ineffective and do not clean or sterilize microbes located in the inner layers of the biofilm [8].…”

Section: Introductionmentioning

confidence: 99%

Curtailing COVID-19 spread in drain pipelines: Using interfacial hydrodynamics for removing Bacterial and Viral Biofilms

Shahabaz¹,

Murallidharan²

2020

Preprint

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Drainage systems contains biological contaminants like bacteria and viruses flowing through them. Additionally, these pipelines also have organic matter known as biofilms growing on their walls. These biofilms infact act as incubation zones for further growth of bacteria and coronaviruses. Standard water treatment routines with traditional cleaning agents are known to be not be able to clean or sterilize microbes located in the inner layers of the biofilm. A recent study has identified specialised fluids which are effective in removing biofilms but these need to be used prudently. The present study proposes to use ‘ interfacial hydrodynamics’ to ensure that the cleaner-fluid (CF) is transported effectively to the location of the biofilms at the pipe walls, and allowed to be in contact with the biofilms for a sufficient amount of time so as to ensure its effective removal. The present study has used CFD technique of Multi-fluid VOF and has demonstrated that relative superficial velocities of cleaner- fluids and sewage water can be controlled, so as to achieve flow regimes that ensure delivery of cleaner fluid to the periphery of the tube walls. Our simulations indicate that most effective cleaning can be achieved by using a cleaner-fluid with a high viscosity ( ~5000 cP)). In such cases, a low- medium velocity (~0.05-0.3 m/s) of CF and water would ensure that the cleaner fluids are in constant contact with the pipe walls. Other suitable viscosity and velocity combinations have also been proposed. Flow parameters that can be used to monitor and cross-verify expected flow patterns on-site have also been proposed.

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The limitations of hydrodynamic removal of biofilms from the dead-ends in a model drinking water distribution system

Cited by 17 publications

References 44 publications

Overview on the hydrodynamic conditions found in industrial systems and its impact in (bio)fouling formation

Overview on the hydrodynamic conditions found in industrial systems and its impact in (bio)fouling formation

Detection of Biofilm on Water Supply Technical Materials with the Application of an Impedance Sensor

Curtailing COVID-19 spread in drain pipelines: Using interfacial hydrodynamics for removing Bacterial and Viral Biofilms

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