Water quality and daily temperature cycle affect biofilm formation in drip irrigation devices revealed by optical coherence tomography

In the reclaimed wastewater reuse using drip irrigation, one of the main issues is the bio-clogging of drippers and decrease of water distribution efficiency in field level. However, the relation between the complex flow created along the dripper (in general formed by a milli-channel with labyrinth geometry) and the biofouling development are rarely studied. In order to improve the knowledge of these mechanisms, the objective was to combine the numerical flow simulations to three-dimensional measurements of biofilm along a milli-fluidic system (nominal flow rate 1L/h) fed by treated wastewater. At first, using the Optical Coherence Tomography (OCT) method and based to Qian et al, 2018 studies, the bio-clogging structure was measured at different levels of fouling (up to 77% of channel volume). Secondly, the new fouled dripper geometries were integrated to 3D CFD models (using comsol multiphysics software) to analyse the effect of biofilm on flow topology and the dripper hydraulic parameters (pressure drop, shear stress, turbulence kinetic energy in particular). The results show that the main areas of biofilm growth correspond to vortices zones where fluid velocity, turbulent kinetic energy values and shear stress are lowest. When the level of clogging increases, the numerical plot of stream lines show local perturbation and reduction of vortices areas caused by their interactions with the biofilm structure. There is also a gradual increase in pressure drop along the milli-channel comparing to initial clean dripper. Finally, by characterising the flowrate in function of inlet pressure and according to Karmeli, 1977, the increase of biofilm formation induces also a modification of the global flow regime in the dripper, i.e. the transfer from a turbulent to a laminar regime. Qian, J., Horn, H., Tarchitzky, J., Chen, Y., Katz, S., Wagner, M., (2017). Water quality and daily temperature cycle affect biofilm formation in drip irrigation devices revealed by optical coherence tomography. Biofouling 33, 211&#8211;221.&#160; Karmeli, D. (1977). Classification and flow regime analysis of drippers. J Agric Eng Res 22:165&#8211;173

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In-situ assessment of biofilm formation in submerged membrane system using optical coherence tomography and computational fluid dynamics

Journal of Membrane Science ◽

10.1016/j.memsci.2016.09.004 ◽

2017 ◽

Vol 521 ◽

pp. 84-94 ◽

Cited By ~ 40

Author(s):

Luca Fortunato ◽

Adnan Qamar ◽

Yiran Wang ◽

Sanghyun Jeong ◽

TorOve Leiknes

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Optical Coherence Tomography ◽

Biofilm Formation ◽

Membrane System ◽

Optical Coherence ◽

In Situ Assessment

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Errata: Visualizing biofilm formation in endotracheal tubes using endoscopic three-dimensional optical coherence tomography

Journal of Biomedical Optics ◽

10.1117/1.jbo.21.2.029802 ◽

2016 ◽

Vol 21 (2) ◽

pp. 029802 ◽

Cited By ~ 1

Author(s):

Andrew E. Heidari ◽

Samer Moghaddam ◽

Kimberly K. Truong ◽

Lidek Chou ◽

Carl Genberg ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Biofilm Formation ◽

Three Dimensional ◽

Optical Coherence ◽

Endotracheal Tubes

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Insights into the Development of Phototrophic Biofilms in a Bioreactor by a Combination of X-ray Microtomography and Optical Coherence Tomography

Microorganisms ◽

10.3390/microorganisms9081743 ◽

2021 ◽

Vol 9 (8) ◽

pp. 1743

Author(s):

Susanne Schaefer ◽

Jakob Walther ◽

Dorina Strieth ◽

Roland Ulber ◽

Ulrich Bröckel

Keyword(s):

Optical Coherence Tomography ◽

Biofilm Formation ◽

Outer Region ◽

Optical Coherence ◽

X Ray ◽

Spatially Resolved ◽

Phototrophic Biofilms ◽

Quantitative Monitoring ◽

Interest In Research ◽

First Time

As productive biofilms are increasingly gaining interest in research, the quantitative monitoring of biofilm formation on- or offline for the process remains a challenge. Optical coherence tomography (OCT) is a fast and often used method for scanning biofilms, but it has difficulty scanning through more dense optical materials. X-ray microtomography (μCT) can measure biofilms in most geometries but is very time-consuming. By combining both methods for the first time, the weaknesses of both methods could be compensated. The phototrophic cyanobacterium Tolypothrix distorta was cultured in a moving bed photobioreactor inside a biocarrier with a semi-enclosed geometry. An automated workflow was developed to process µCT scans of the biocarriers. This allowed quantification of biomass volume and biofilm-coverage on the biocarrier, both globally and spatially resolved. At the beginning of the cultivation, a growth limitation was detected in the outer region of the carrier, presumably due to shear stress. In the later phase, light limitations could be found inside the biocarrier. µCT data and biofilm thicknesses measured by OCT displayed good correlation. The latter could therefore be used to rapidly measure the biofilm formation in a process. The methods presented here can help gain a deeper understanding of biofilms inside a process and detect any limitations.

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