project

Safeguarding drinking water treatment processes with natural viruses

Sources for the production of drinking water are increasingly under pressure, partly due to urbanisation, industrialisation and climate change. As a result, alternative sources are being used more frequently, but these are often more polluted than current sources. This puts increasing pressure on treatment processes, which must continuously and effectively remove risky and undesirable particles, chemical compounds and micro-organisms to ensure the delivery of high-quality drinking water. Ideally, the effectiveness of individual treatment steps and the entire purification train should be continuously monitored so that any defects and/or deviations can be quickly spotted and remedied. 

Challenge

This continuous monitoring is challenging, especially because very high removal efficiencies need to be demonstrated and external indicators may not be dosed. 

Solution

KWR has developed a method using natural viruses (NVs) as indicators to determine removal efficiency. NVs occur continuously in many surface water sources in high concentrations (around 10⁸ copies/L), are small (50–80 nm), and can be analysed with low detection limits using qPCR. Previous research has already gained experience with this technique to measure across different systems. 

A number of relevant research questions remain open, requiring further knowledge development and currently hindering the implementation of the NV method in practice, notably: 

  • Understanding how NV markers can be applied in practice for integrity monitoring of full-scale drinking water treatment plants for different treatment steps (and in which situations the method is not/less suitable). 
  • Measurement technology to perform the NV method on-site for routine monitoring. 
  • Better understanding of the functioning of NV markers as a monitoring tool by gaining more insight into the properties of the viruses. 
  • (Further) development of new NV markers for different types of water used as sources for drinking water production, such as various types of groundwater and seawater. This would enable the NV method to be used for treatment plants using sources other than surface water. 

The approach of this project is as follows:

  • One full-scale drinking water treatment plant will be subjected to high-frequency monitoring with the NV method for one year to assess its practical suitability for integrity monitoring. 
  • An existing technique for on-site qPCR analysis of bacteria in water is being further developed for semi-automated monitoring of NV markers on-site. This mainly concerns developments in automation and on-site concentration of viruses from water. 
  • Research is being conducted into the properties of the natural viruses used or intended as markers. This mainly concerns properties such as charge, shape, size, host, and spatial and temporal variation. 
  • NV markers for surface water use are currently available for research. Several candidates have been developed in previous research for seawater and groundwater. These will be tested to assess their suitability for further development and application as NV markers. 

Expected outcome

The project will deliver the knowledge and technology needed to apply the NV method in practice for integrity monitoring of drinking water treatment plants. Specifically, this should result in a new method for operational monitoring of treatment integrity, with a particular focus on membranes and other physical removal steps.