Membrane Integrity

Monitor integrity of membranes in water treatment and measure microbial levels during the process.

Membrane Integrity Monitoring

Membranes play an important role in water treatment processes. Microbiological contamination is a huge issue in operation of membranes and can lead to a complete failure of process operation.

Up to now it had not been possible to detect rapidly and precisely where contamination is located within a bulk of membranes, to enable controlled cleaning and exchange of defect or contaminated membranes. This applies for other type of filters as well.

By knowing the actual microbiological contamination level as provided by the ColiMinder measurements, it is now possible to control membrane activity and integrity:

  • automatic sampling from the permeate collection tank to determine the bacterial contamination at any stage of membrane filtration process in water treatment
    correlating contamination peaks with membrane switching intervals allows to identify faulty modules
    receive warnings as soon as a certain threshold level is exceeded
  • allowing interpretation whether contamination is caused by a microbiological increase or a faulty membrane by the shape of the timeline
  • saving money by preventing complete shut-down of membrane operation
  • reducing disinfection by-products to protect environment and people’s health
  • easy-to-integrate into the process at-line

Benefits of the ColiMinder


In case of contamination events.


In order to increase process efficiency, safety and sustainability


The result timelines (microbiological activity, transmission and intrinsic fluoresence) carry important additional information about the dynamics of your system


throughout the entire water treatment, from intake to effluent


in case of microbiological contamination events, to identify source of contamination.


The ColiMinder bacterial analyzer can be installed at any stage of membrane operation for real-time monitoring of microbiological contamination.

Monitoring permeate contamination level
MBR plants
In standard operation regime
All membrane types possible
Special requirements like cleamning or exchange of defect membranes
Rapid detection of fouling membranes


Detection of defective Membrane Filtration Modules (UF) in WWTP using ColiMinder™ measuring permeate contamination level. Peaks indicate defective filtration modules.


The ColiMinder measures the specific metabolic (enzymatic) activity of the target organisms present in the sample.

The measured value provides information about the energy turnover of living organisms in the sample. Living organisms need energy, which they gain through their metabolism, so the metabolic activity reflects the energetic turnover of the existing microorganisms.

The measured activity directly indicates the faecal or microbiological contamination level of the water.

ColiMinder can automatically monitor any process step – critical control points – in water treatment processes, bottled water production, wastewater water treatment and discharge, industrial and process water treatment and discharge, providing a direct visualization of microbial dynamics of your processes. It also monitors any type of surface water, bathing and recreational water and raw water, be it fresh or saline water, providing a direct visualization of microbial dynamics of the respective water body.

The timeline displays any change in microbial contamination, providing precise and valuable information that was previously unavailable.

Since the results of the ColiMinder are available in near real time, microbiological water quality is now available as an evidence-based decision parameter. In addition, real-time alerts can be sent when defined bacterial contamination limits are exceeded.

The ColiMinder reliably detects any type of contamination, whether it is of fecal or microbial origin.

Different add-on modules are available to ensure stable and reliable sampling and results, even in harsh environmental conditions.

The measured enzymatic activity of the sample provides a direct answer to the questions: “how high is the faecal contamination of the sample?” and “how high is the microbiological contamination of the sample?”

Depending on the reagent used, the measurement results are specific for the corresponding target organism.

The results not only provide direct quantitative information about the microbial contamination of the product, but shape and course of the measurement timeline also contain valuable information about the dynamics of the microbiological load and thus allow conclusions to be drawn about the causes of changes. Depending on the reagent used, the measurement results are specific for the corresponding target organism.

A recent scientific study published in Water Research shows that the ColiMinder is the most sensitive instrument available on the market for monitoring microbial quality of water. Please see: Favere, J., Waegenaar, F., Boon, N., & De Gusseme, B. (2021). Online microbial monitoring of drinking water: How do different techniques respond to contaminations in practice?, published in Water Research Journal.

The reliability of the ColiMinder has been demonstrated in several installations where the devices have been providing reliable measurement results in continuous operation since 2015.

Thanks to the sophisticated system for fully automatic cleaning and calibration, the maintenance effort is limited to refilling the consumables. Replacement of the silicone hoses is recommended every 2 years, otherwise no maintenance is required.

The ColiMinder instruments measure absolutely stable, no manual calibration is necessary as the instruments calibrate themselves automatically at regular intervals.

The ColiMinder can measure any type of sample without pre-treatment.

It has no problem with suspended solids or turbid samples. Even fluctuating background fluorescence has no effect on the measurement result. 

It has an IP65 protected housing and can measure in the 0°C to 40°C temperature range. 

The ColiMinder provides operational monitoring as recommended by the WHO, the EU Drinking Water Directive, and others.

Real-time measurement of current microbiological quality enables rapid response and correction, so the ColiMinder helps you to meet specified limits at the lowest cost and with the highest level of safety.

A correlation between standard lab results and ColiMinder results can be established and used internally but the system is not intended to replace compliance testing.

In contrast to classical culture-based laboratory methods, which are based on the cultivation of bacteria, the enzymatic measurement method of the ColiMinder is based on the direct measurement of the metabolic activity of the target organisms. There is therefore no direct and generally valid conversion between the two methods.

In general, however, a correlation table can be created through comparative measurements, which can then be used for conversion.

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