Application field

Membrane integrity

The ColiMinder is an instrument for monitoring integrity of membranes in water treatment, measuring microbial level in the process fully automatic and in 15 minutes.

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

How does it work?

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.



How do I Use the ColiMinder?

ColiMinder can automatically monitor any process step – critical control points – in water treatment processes, providing a direct visualization of microbial dynamics of your processes.

The timeline displays any change in microbial contamination level, 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 a parameter for process control. In addition, real-time alerts can be sent when defined bacterial contamination limits are exceeded.

The ColiMinder has proven its ability to specifically measure any type of fecal indicator bacteria or total microbial activity. It reliably detects any type of contamination, be it on the permeate or the retendate side of a membrane.

Different add-on modules are available to ensure stable and reliable sampling and results.

How do I use the results?

The measured enzymatic activity of the sample provides a direct answer to the question: “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 in the treatment process, 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.


The analytical capability of ColiMinder in drinking water or wastewater measurements is comparable to that of determinations of HPC or to that of chromogenic coliform agar counts in the case of fecal contamination.

Different scientific studies have evaluated and validated ColiMinder measurements for drinking water and wastewater monitoring.





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 sediments or turbid samples. Even fluctuating background fluorescence has no effect on the measurement result due to the measurement approach.

Its robustness towards environmental influences, like temperature, humidity, chemical load etc., is evident in installations like at Stonecutter Island Sewage Treatment Plant in Hong Kong, where it has been monitoring effluent 24/7 since 2017 without any issues.

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





Can I do compliance testing with the ColiMinder?

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.


Can ColiMinder results be expressed in CFU ?

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.


Receive real-time warning

In case of contamination events

Monitor your process performance

In order to increase process efficiency, safety and sustainability

Learn more about your process

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

Safeguard your water quality

throughout the entire water treatment, from intake to effluent

Scan your membrane operation

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

Detect membrane fouling immediately



At a hospital, the ColiMinder is monitoring permeate of MBR plant prior to discharging it close to a recreational area.

Result timeline of membrane permeate monitoring

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

ColiMinder use cases

proven by customers!

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


For more information:

Several White Papers can be found here in the download area to provide further information about drinking water measurements with the ColiMinder.


The ColiMinder™ had proven its reliability and stability in various drinking water applications world-wide


Austrian municipal drinking water production from groundwater well: the ColiMinder monitoring raw water intake and after activated carbon filtration in alternating mode.

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