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.
Highlights
Biofilms are endemic within drinking water distribution systems (DWDS) and can impact water quality, yet current water quality sampling and monitoring is typically restricted to the accessible bulk water, which is not representative of the quantity or composition of biofilms at the pipe wall
The biofilm monitoring device (BMD) was first verified in the laboratory to confirm that the optimum length, orientation and flow rate of the device to produce consistent results, the BMD was successfully validated by installing within operational DWDS
The BMD assessed different biofouling rates at the sites studied and these rates were found to have a positive correlation with the number of discolouration customer contacts, suggesting this is a viable and rapid technique to assess network performance
Summary
Biofilms are endemic within drinking water distribution systems (DWDS) and can impact water quality, yet current water quality sampling and monitoring is typically restricted to the accessible bulk water, which is not representative of the quantity or composition of biofilms at the pipe wall. Discolouration events are a leading example of distributed water quality failure that occur worldwide They impact consumer confidence and as a major cause of customer contacts, they are used as a service indicator in the United Kingdom, with performance linked to financial rewards or penalties (Vreeburg and Boxall, 2007; OFWAT, 2021). Discolouration has been described as a three-step process consisting of low-level material supply, the accumulation of this material on pipe surfaces and its rapid mobilisation into the bulk water (Boxall et al, 2001). This behaviour has been verified worldwide in the empirical PODDS
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
