Intermittent Water Supply Impacts on Distribution System Biofilms and Water Quality

Preciado, Carolina Calero; Husband, Stewart; Boxall, Joby; Olmo, Gonzalo Del; Soria‐Carrasco, Víctor; Maeng, Sung Kyu; Douterelo, Isabel

doi:10.1016/j.watres.2021.117372

Cited by 28 publications

(24 citation statements)

References 56 publications

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“…Similarly, the variability in DBP formation among the Mirpur and Tongi drinking water samples suggests some were subject to infiltration by contaminated water between the well and the residential storage tanks. While the intermittent operation of distribution systems can enhance biofilm growth in pipes, and thus DBP precursor shedding following repressurization, this cannot explain the observed differences in sucralose concentrations (Figure C).…”

Section: Resultsmentioning

confidence: 99%

Effects of Intrusion on Disinfection Byproduct Formation in Intermittent Distribution Systems

et al. 2022

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Intermittently operated distribution systems serve over one billion people and may be impacted by the intrusion of contaminated waters carrying disinfection byproduct (DBP) precursors. The impact of intrusion on the formation of 19 DBPs was evaluated in an intermittent water system supplied by deep aquifers in Dhaka, Bangladesh. Untreated piped water samples were collected from residential taps and chlorinated under controlled conditions. Chloride, dissolved organic carbon, and the artificial sweetener sucralose were measured as indicators of intrusion. Most piped water samples had low concentrations of DBPs and indicators; however, a subset had higher levels of DBPs and indicators, suggesting the intrusion of contaminated water into the distribution system, particularly during the rainy season. Piped water samples with evidence of intrusion typically formed higher concentrations of haloacetaldehydes and haloacetonitriles when chlorinated, which greatly increased the calculated cytotoxicity. DBP formation and calculated cytotoxicity in piped water samples impacted by intrusion were comparable to those in piped water samples supplied by horizontal and vertical recharge-impacted groundwaters, yet lower than piped surface waters from other regions of Dhaka. The results demonstrated that intrusion can increase DBP formation in an unpredictable fashion, highlighting the need to sample from many locations in intermittent water systems to accurately evaluate DBP exposure risk.

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Section: Resultsmentioning

confidence: 99%

Effects of Intrusion on Disinfection Byproduct Formation in Intermittent Distribution Systems

et al. 2022

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“…The range of shear stress (τ avg = 3.5 Pa) here resembles the range in blood vessels (on the order of 1 Pa) 49 and bio lm reactors (1.0 to 2.5 Pa) 51 . Additionally, the uctuation periods used in this study (5.6 minutes to 6 hours) resemble the durations of rainfall events (15 minutes to few hours) 52 , intermittent time period of water supply system (6 hours) 32 , and hydraulic retention time in the operation process of moving bed bio lm reactors (MBBR) (10 hours) 53 . Therefore, our results have potential implications for predicting and controlling bio lm development in natural and engineered systems, such as the drinking water distribution systems and medical devices, where bio lms are consistently exposed to uctuating ows 22,25,27 .…”

Section: Discussionmentioning

confidence: 99%

“…The frequency f = 1/2T, T represents the time duration under low or high shear stress. Three frequency cases were considered in this study and denoted as low-frequency (LF, frequency f = 2×10 − 5 Hz, the duration for low or high shear stress T LF is 6 hours), medium-frequency (MF, f = 2×10 − 4 Hz, T MF = 45 minutes) and high-frequency (HF, f = 1×10 − 3 Hz, T HF = 5.6 minutes), varies by approximately three orders of magnitude, which resembles the durations of rainfall events 52 , intermittent water supply time (IWS) period 32 , and hydraulic retention time in the moving bed bio lm reactors (MBBR) operation process 53 . As the bio lms grow, we captured images of bio lms using a Confocal Laser Scanning Microscope (CLSM) at 10 to 30-minute intervals, depending on the frequency.…”

Section: Bio Lm Development Experimentsmentioning

confidence: 99%

“…Kooij et al (2020) cultivated Legionella pneumophila bio lms on metallic materials and reported that uctuating ow promoted bio lm formation rate 31 . Preciado et al (2021) found that shorter intermittent periods lead to the production of higher proportion of aromatic organic compounds 32 . Despite the recognition of the important control of ow uctuations on the biological and chemical characteristics of bio lms, there is a lack of knowledge on how ow uctuations control bio lm thickness and morphological structures.…”

Section: Introductionmentioning

confidence: 99%

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Microfluidic investigation of the impacts of flow fluctuations on the development of Pseudomonas putida biofilms

Wei

Yang

2023

Preprint

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Biofilms play critical roles in wastewater treatment, bioremediation, and medical-device-related infections. Understanding the dynamics of biofilm formation and growth is essential for controlling and exploiting their properties. However, the majority of current studies have focused on the impact of steady flows on biofilm growth, while flow fluctuations are commonly encountered in natural and engineered systems such as water pipes and blood vessels. Here, we investigated the effects of flow fluctuations on Pseudomonas putida biofilm growth through systematic microfluidic experiments and developed a theoretical model to account for such effects. Our experimental results revealed that biofilm growth under fluctuating flow conditions followed three phases: lag phase, exponential phase, and fluctuation phase. In contrast, we observed the four phases of biofilm growth under steady-flow conditions, i.e., lag, exponential, stationary, and decline phases. Furthermore, we demonstrated that low-frequency flow fluctuations promoted biofilm growth, while high-frequency fluctuations inhibited its development. We attributed the contradictory impacts of flow fluctuations on biofilm growth to the adjust time needed for biofilm to grow. Based on the experimental measurements, we developed a theoretical model to predict the growth of biofilm thickness under fluctuating flow conditions. Our study provides insights into the mechanisms underlying biofilm development under fluctuating flows and can inform the design of strategies to control biofilm formation in diverse natural and engineered systems.

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“…All bulk water samples were collected in triplicates of 500 mL and measured in-situ, excluding TCC and ICC for which triplicates of 15 mL were collected for analysis in the laboratory. Bulk water samples for planktonic TCC and ICC water were dechlorinated prior to analysis-a 4.5 µL volume of a 1% (w/v) sodium ascorbate solution was added to each 15 mL sample (using a 1% sodium ascorbate solution) (Fish et al, 2020 andPreciado et al, 2021).…”

Section: Bulk Water Samplingmentioning

confidence: 99%

Non-invasive Biofouling Monitoring to Assess Drinking Water Distribution System Performance

et al. 2021

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Biofilms are endemic in drinking water distribution systems (DWDS), forming on all water and infrastructure interfaces. They can pose risks to water quality and hence consumers. Our understanding of these biofilms is limited, in a large part due to difficulties in sampling them without unacceptable disruption. A novel, non-destructive and non-disruptive biofilm monitoring device (BMD), which includes use of flow cytometry analysis, was developed to assess biofouling rates. Laboratory based experiments established optimal configurations and verified reliable cell enumeration. Deployment at three operational field sites validated assessment of different biofouling rates. These differences in fouling rates were not obvious from bulk water sampling and analysis, but did have a strong correlation with long-term performance data of the associated networks. The device offers the potential to assess DWDS performance in a few months, compared to the number of years required to infer findings from historical customer contact data. Such information is vital to improve the management of our vast, complex and uncertain drinking water supply systems; for example rapidly quantifying the benefits of improvements in water treatment works or changes to maintenance of the network.

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Intermittent Water Supply Impacts on Distribution System Biofilms and Water Quality

Cited by 28 publications

References 56 publications

Effects of Intrusion on Disinfection Byproduct Formation in Intermittent Distribution Systems

Effects of Intrusion on Disinfection Byproduct Formation in Intermittent Distribution Systems

Microfluidic investigation of the impacts of flow fluctuations on the development of Pseudomonas putida biofilms

Non-invasive Biofouling Monitoring to Assess Drinking Water Distribution System Performance

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