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

Abstract

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.

Emerging investigator series: optimisation of drinking water biofilm cell detachment and sample homogenisation methods for rapid quantification via flow cytometry

“…The BMD consisted of a series of short and identical polyethylene pipe lengths (53 mm) suitable for biofilm sampling, which can be connected directly to an operational drinking water supply. 16 A flow valve was attached to the outlet (Akro Valves Ltd, UK) to maintain a consistent flow rate of 1 L min −1 with a shear stress of 0.16 Pa. 16 The biofilms used in the removal and homogenisation experiments were grown in a BMD for either 3 or 6 months.…”

“…Understanding and characterising biofilms or the biofouling rate within DWDS is critical to plan the type and frequency of network interventions. 16…”

“…20,21 Others remove biofilm by brushing the sampled surface such as PWG coupons that have been inserted into drinking water pipes in a full-scale facility or an operational network. 16,17,22…”

Moving beyond silver in point-of-use drinking water pathogen control

“…In situ biofilm assessment in real systems is challenging due to (1) the biofilm location within the POU device and the intricate pipe network, making nondestructive access difficult, (2) the spatial heterogeneity of biofilms with variations in microbial composition and thickness at different locations within the plumbing system 29,30 (3) temporal changes in biofilms influenced by factors such as water flow, temperature, and disinfection practices, and (4) sampling methods for biofilm assessment can be invasive and disruptive to the plumbing system, potentially affecting the biofilm structure and composition. 31 These challenges highlight the need to develop nondestructive methods for accurately assessing and monitoring biofilms in situ, possibly by employing localized sensors and machine learning techniques. For example, ATP and electrochemical sensors have been developed to monitor activity in biofilms.…”

La importancia de la temperatura del agua en las redes de abastecimiento

“…Este tipo de estudios son fundamentales para comprender las características de las biopelículas en diferentes situaciones y las consecuencias derivadas del fenómeno de cambio climático en la calidad del agua suministrada. Además de estar asociado a un aumento de las temperaturas medias, el calentamiento global traerá consigo un aumento de la frecuencia y magnitud de los fenómenos extremos, como las olas de calor, que ya empiezan a percibirse en la monitorización del crecimiento microbiano en algunos sistemas (Pick et al, 2021).…”