Online flow cytometry in drinking water production: a case study

Ensuring safe and clean drinking water is a top priority for municipalities worldwide. In Lausanne, Switzerland, the local water supplier, Service de l’eau, implemented innovative techniques to monitor and optimise water quality. One of the most effective methods they’ve employed is online flow cytometry, a cutting-edge technology allowing for real-time monitoring of microbial populations throughout the water treatment process. 

Let’s further explore how online flow cytometry was used to assess filtration and disinfection efficiency at Lausanne’s water treatment facilities. 

The role of online flow cytometry in water quality monitoring 

Online flow cytometry has revolutionised how water treatment plants monitor microbial levels, providing immediate, accurate data that helps make timely decisions. Traditional methods, like laboratory-based sampling, can delay results by 24 to 72 hours, but with online flow cytometry, results are available in minutes—in our case, around 20. This speed is crucial in identifying and addressing potential water quality issues before they affect the public. 

Case study: Lausanne’s water treatment process

Lausanne’s water treatment facilities employ various techniques to ensure drinking water meets the highest standards. In a study conducted between January and August 2019, Service de l’eau used online flow cytometry to evaluate the effectiveness of different treatment stages, particularly filtration and disinfection. 

Key findings

1. Sand filtration: the study revealed that sand filtration alone doesn’t significantly reduce microbial content. This process mainly acts as a physical barrier, trapping larger particles but not eliminating bacteria. Only after chlorination was a substantial reduction in bacterial count observed in the final disinfection step.
   

2. Chlorination: chlorination proved highly effective, reducing the number of intact bacterial cells by a factor of 100. This step ensures that the water entering the distribution network is safe for consumption.
   

3. Ultrafiltration: on the other hand, ultrafiltration was an excellent disinfection method, achieving reduction factors between 1,000 and 10,000 in the total number of intact cells. This process physically removes bacteria, acting as a robust barrier to microbial contamination. 
   

Comparing online flow cytometry to traditional methods

The measurements obtained using the BactoSense automatic online flow cytometer were consistent with those gathered through traditional laboratory methods. This validation confirms the reliability of online flow cytometry as a tool for continuous water quality monitoring. By providing real-time data, this technology enables more proactive management of water treatment processes, reducing the reliance on periodic sampling and delayed results.

Benefits of online flow cytometry in drinking water production

Online flow cytometry offers several advantages for water treatment facilities. These include:

• Real-time monitoring: provides immediate feedback on water quality, allowing for quick adjustments to treatment processes.
  

• Enhanced accuracy: delivers precise microbial counts, ensuring effective disinfection processes. 
  

• Cost-effective: reduces the need for frequent laboratory tests, cutting operational costs.
  

• Improved safety: early detection of microbial contamination helps prevent potential health risks to the public.

Safeguarding public health with reliable monitoring

The use of online flow cytometry in Lausanne’s water treatment plants demonstrates the technology’s potential to enhance the safety and quality of drinking water. Water suppliers can ensure more consistent and reliable monitoring by integrating this advanced method into their operations, ultimately safeguarding public health.

Online flow cytometry presents a valuable solution for water treatment facilities aiming to modernise their quality control processes. Its ability to provide real-time, accurate data makes it an indispensable tool for cleaner, safer drinking water.

Learn how online flow cytometry can optimise your water treatment processes and enhance microbial monitoring in your facility with a demo.