Chlorine filtration in dialysis: how advanced sensing is raising the bar

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In 2022, more than 30,000 people in the UK were undergoing kidney dialysis. For every one of those patients, water quality is not a background consideration but a frontline safety issue. Dialysis machines rely on large volumes of treated water, and any trace contaminants that remain can pass directly into the bloodstream. Among the most critical of these contaminants is chlorine.

Chlorine is essential for the disinfection of drinking water, protecting public health by controlling microbial growth. However, what is beneficial at the municipal supply level becomes dangerous once water is used for haemodialysis. Even trace levels of free chlorine or chloramines can damage red blood cells, cause haemolysis and lead to serious patient harm. As a result, dialysis water treatment systems must reliably remove chlorine and continuously verify that removal is effective.

The role of carbon filters in dialysis water treatment

Granular activated carbon (GAC) filters are the established solution for removing chlorine in dialysis plants. Installed upstream of reverse osmosis (RO) membranes and dialysis machines, these filters adsorb chlorine and in most cases chloramines too, protecting both patients and sensitive downstream equipment, helping to ensure a continuous supply of purified water.

However, GAC filters are consumable assets. Their performance degrades over time depending on inlet chlorine concentration, water flow rates and total throughput. If a filter becomes saturated with chlorine without detection, chlorine breakthrough can occur suddenly. For dialysis centres and hospitals, this makes effective monitoring essential.

Best practice requires measuring chlorine both before and after the carbon filters. At the inlet, operators need to understand the incoming chlorine load and track trends over time. At the outlet, they must continuously confirm zero chlorine conditions. Any delay in detection increases the risk of exposure, which is why response time and measurement reliability are so critical.

Limitations of traditional chlorine monitoring

Historically, chlorine measurement has relied on either amperometric sensors with electrolyte buffers or colourimetric analysers. While both technologies are well established, neither is ideally suited to high criticality healthcare applications.

Traditional amperometric probes typically have T90 response times of two to three minutes and require frequent maintenance. Electrolytes must be replenished, membranes cleaned and electrodes manually serviced to remove scaling. Measurement accuracy is also sensitive to pH drift, often necessitating offline verification.

Colourimetric analysers offer good accuracy but at the cost of speed and complexity. Reagents must be handled and replaced, and while full reaction times can be completed in 2 to 3 minutes, sampling frequency is often reduced to once every 15 minutes to an hour to save on costly reagent consumption. For dialysis water systems, where rapid response to chlorine breakthrough is essential, these delays can compromise safety margins.

A new approach to verifying filter performance

This is where Bürkert’s MS02 Chlorine Cube sensor offers a new solution. Originally developed for demanding pharmaceutical and drinking water applications, the MS02 has proven particularly well suited to monitoring GAC filters in dialysis water treatment systems.

The MS02 uses an innovative amperometric on chip design protected by an immobilised membrane, eliminating the need for electrolyte buffers. This allows it to achieve a T90 response time of around 30 seconds, dramatically faster than conventional technologies. For dialysis applications, that speed means faster alarms, quicker intervention and reduced risk to patients.

Crucially, the MS02 is sensitive enough for zero chlorine measurement, making it ideal for monitoring the outlet of carbon filters. Its stable floating zero point avoids polarisation effects and removes the need for artificial chlorine dosing, simplifying system design and validation. With no reagents and minimal maintenance requirements, the sensor supports long service intervals. Users have reported continuous operation for over two years without recalibration.

Bürkert’s wider role in dialysis technology

Chlorine monitoring is only one part of the dialysis process, and Bürkert’s involvement goes far beyond sensing. The company works closely with dialysis machine manufacturers through its global network of Systemhaus locations, supporting projects from concept development through to full scale production.

A notable example is Bürkert’s collaboration with a leading manufacturer on its latest dialysis machine. By developing a compact, integrated fluidic assembly incorporating valves, sensors and pumps, Bürkert helped simplify setup, reduce error risk and improve workflow efficiency for clinical staff.

All components are designed to meet stringent medical standards for hygiene, durability and biocompatibility, while also supporting quieter operation for home and nocturnal dialysis environments.

This systems level expertise is increasingly important as dialysis treatment evolves. With more patients opting for home haemodialysis or overnight therapies, manufacturers face growing demands for compact, reliable and user friendly equipment that does not compromise on safety.

chlorine filtration — Periodic maintenance is simple with plug-and-play design.

Recognition for innovation

The significance of Bürkert’s advances in chlorine measurement has recently been recognised by the industry. The MS02 Chlorine Cube sensor was recently awarded Highly Commended Sensor Product of the Year by a leading industry magazine, underlining its impact in high criticality applications such as healthcare and water treatment.

Safeguarding patients through better sensing

As the global incidence of chronic kidney disease continues to rise, the pressure on dialysis infrastructure will only increase. Ensuring that every litre of water used in treatment is free from harmful chlorine is a non negotiable requirement.

By combining proven carbon filtration with fast, accurate and low maintenance chlorine sensing, dialysis providers can significantly reduce risk while improving operational confidence. Bürkert’s MS02 sensor, alongside its broader expertise in fluid control and medical system integration, demonstrates how innovative engineering can translate directly into safer outcomes for patients and greater assurance for clinicians and operators alike.

For UK healthcare providers, investing in advanced chlorine monitoring technologies is not just a matter of compliance, but a critical step in delivering safe, reliable and future ready dialysis treatment.

Bürkert Fluid Control Systems
Greg Wainhouse, Regional Business Development Manager – Industrial Water, North Europe
Tel.: +44 1285 64 87 20
sales.uk@burkert.com
www.burkert.co.uk

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Burkert Fluid Control Systems

01285648720
sales.uk@burkert.com
http://www.burkert.com/
Fluid Control Centre 1 Bridge End Gloucestershire Cirencester GL7 1QY GB

About us

Bürkert is present in thirtyfive countries around the world. We also work with a large network of distributors and partners, which means we are as close as possible to our customers. This global presence ensures full service and support to all of our customers in every country around the world. Research is the lifeblood of our company.

At Bürkert, we are never satisfied with the status quo and are continually seeking new technologies and solutions for our customers. Every year, our people develop new and highly advanced products and solutions, ranging from integrated process measurement and control units to the most sophisticated systems used in pharmaceutical research. To be a market leader, we are also an R&D leader.

Therefore, our investment in research & development is one of the highest in our industry. In our research centres in Germany and France, 150 people are committed to working for a common future for our company and our customers. We are committed to offering our expertise wherever it is needed, anywhere in the world. This global presence ensures that our advances in fluid control technology are also global.

What we do in a nutshell

Manufacture of process equipment. One of the few manufacturers to provide solutions for the complete control loop.

Where we supply to

UK Ireland, Europe

Industries we supply to

Food and Beverage, Pharmaceutical Cosmetics Toiletries, Water and Wastewater

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