project

Safeguarding drinking water treatment processes with indigenous 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 detected 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 indigenous viruses (IV) as indicators to determine removal efficiency and treatment integrity. IVs 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 in 1L samples. Previous research has already gained experience with this technique to measure across different treatment systems. 

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

  • Understanding how IV 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 IV method on-site for routine monitoring. 
  • Better understanding of the functioning of IV markers as a monitoring tool by gaining more insight into the properties of the viruses. 
  • (Further) development of new IV 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 IV 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 IV 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 IV 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 indigenous viruses used or intended as markers. This mainly concerns properties such as charge, shape, size, host, and spatial and temporal variation. 
  • IV 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 IV markers. 

Expected outcome

The project will deliver the knowledge and technology needed to apply the IV 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.