Level 1
General — Microbial Water Quality
Broad questions about online microbial monitoring for newcomers and decision-makers.
Online microbial monitoring means measuring the microbiological quality of water continuously and automatically, directly at the measurement point — without sending samples to a laboratory. Instead of waiting 1–5 days for manual, culture-based results, online instruments deliver data in minutes, enabling real-time process control, early warning, and faster decision-making.
Traditional culture-based methods (CFU, membrane filtration, MPN) require 18–48 hours for incubation, plus sampling and transport time — meaning results arrive 1–5 days after the event. By then, contaminated water may already have been distributed, consumed, or used in production. Online monitoring closes this gap by detecting microbial changes in real time, allowing operators to react before harm occurs.
Fecal indicator organisms (FIO), also known as fecal indicator organisms (FIB) — primarily E. coli, Enterococci or coliforms — are bacteria that originate in the intestines of warm-blooded animals. Their presence in water signals fecal contamination and the potential presence of pathogens such as Salmonella, Norovirus, or Cryptosporidium. Monitoring FIO (FIB) is the standard approach to assessing microbiological water safety under WHO guidelines and the EU Drinking Water Directive.
Enzymatic activity measurement measures specific enzymes produced by target organisms directly in the water sample. For E. coli, the enzyme β-D-Glucuronidase (GUS) is highly specific — it is produced almost exclusively by E. coli organisms. A fluorogenic substrate is added to the sample; if E. coli is present, the enzyme cleaves the substrate, producing a measurable fluorescence signal within minutes. The signal is proportional to the number of active (living) organisms.
Investment costs for online microbial monitoring instruments typically range from tens to hundreds of thousands of Euros depending on the technology, number of measurement points, and required add-on modules. Operating costs include reagents, software licences, and service contracts. For ColiMinder, the total cost of ownership is competitive when compared to the cost of continuous manual lab sampling — especially when factoring in the value of real-time data for process optimization and incident prevention. Feel free to Contact us for a project-specific quote.
Level 2
Online Microbial Monitoring
Technology and regulatory context — product-independent background knowledge.
The ColiMinder measures live energy whereas the traditional method measures cultivability. Thus, a correlation cannot be 100% as different parameters are measured. However, there have been numerous scientific and customer studies comparing results of both methods, and the correlation is usually in a range between r2 = 0.7 to 0.9. It is highly recommended to follow the guidelines for internal validation provided by the ColiMinder team.
Time is money!
The benefits of using the online microbial monitoring devices vary from one application to another, but in general there are quite a few of them:
- optimization of treatment processes addressing microbial water quality
- increased water re-use rate
- savings in direct process costs by controlling dosing of disinfectants
- optimizing membrane operation, ensuring membrane, filter and RO integrity
- design of new treatment processes
- optimizing CIP and SIP
- Rapid release of produced batches
- saving manual plate tests in the lab
Only enzymatic measurements provide specific results for target organisms such as E. coli. The results are easy to understand and do not require additional interpretation. It is the most sensitive measurement approach on the market for online microbial monitoring.
Rapid microbiological methods (RMMs) detect microbial presence or activity without traditional culture incubation. Common approaches include:
- Enzymatic / fluorogenic substrates — detect enzyme activity of specific organisms (e.g., ColiMinder)
- Flow cytometry — counts and characterizes individual cells using laser light
- ATP bioluminescence — measures total cellular energy as a proxy for biomass
- qPCR — detects specific DNA sequences; requires sample preparation
Pathogenic organisms (e.g., Norovirus, Cryptosporidium, Salmonella) are present in very low concentrations in most water samples and are difficult and expensive to detect individually. Fecal indicator organisms like E. coli are far more abundant when fecal contamination occurs, are reliably correlated with pathogen presence, and are much easier to measure. Regulatory frameworks (WHO, EU Drinking Water Directive 2020/2184) therefore use E. coli and Enterococci as proxy indicators for water safety. E.g., in a scientific study by Burnet et.al. (2021), ColiMinder (GLUC) measurements proved to have a signficant correlation to the presence of waterborne pathogens.
Key regulatory frameworks include:
- WHO Guidelines for Drinking-water Quality (4th edition) — recommends a risk-based approach (Water Safety Plans) with operational monitoring for E. coli
- EU Drinking Water Directive 2020/2184 — mandates E. coli and Enterococci monitoring; encourages risk-based monitoring aligned with WHO WSP
- EU Bathing Water Directive 2006/7/EC — requires E. coli and Enterococci monitoring at designated bathing sites
- EU GMP Annex 1 (Pharma) — requires microbiological monitoring of water used in sterile manufacturing
| Culture-based (lab) | Enzymatic (ColiMinder) | |
|---|---|---|
| Time to result | 18–48 h (+transport) | 15 minutes |
| Manual intervention | each test requires staff | full autonomy for up to 1,000 measurements |
| Automation | Manual | Fully automatic |
| Reproducibility | low (+/-30% deviation) | high (+/- 2% deviation) |
| Continuous monitoring | Not possible | Up to 48×/day |
For operational monitoring and process control, rapid methods like ColiMinder provide superior value — they enable real-time decisions that lab methods simply cannot support. For regulatory compliance testing (e.g., official drinking water quality reports), most authorities still require culture-based reference methods. In practice, ColiMinder is deployed alongside traditional lab testing: the instrument monitors continuously for anomalies, and results are used to trigger targeted lab confirmation when needed. This reduces the overall number of lab tests while dramatically increasing monitoring frequency and optimizing quality protocols.
Level 3
ColiMinder — Product Questions
Technical details, operation, and purchasing questions about ColiMinder.
The benefit of the ColiMinder is its flexibility – it can be used as an inline process monitoring instrument but also in the lab for manual testing. To facilitate the latter application, a sampling carousel for 12/24 automated samples is offered as an add-on module. Also, a dual use is possible by using one out of two sample intakes for automated sampling from the process and the second sample intake for measuring grab samples.
There is no need to interpret the results: a high result means high contamination – a low result means a low contamination.
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 of the sample, but the shape and course of the measurement timeline contain valuable information about the dynamics of the microbiological load and thus allow conclusions to be drawn about the causes of changes.
The measurement cycle of the ColiMinder works fully automatic from sampling through measurement, cleaning and re-calibration with autonomy for up to 1,000 measurements. The measurement itself consists of 4 steps: sample is automatically taken in from a water line and mixed with reagents, after which specific enzymes react with a substrate and release a fluorescent signal. This fluorescence is measured optically over time to determine the concentration of target microorganisms. The resulting data are processed automatically and made available in real time, enabling rapid detection and continuous monitoring of water quality. All this takes place in as little as 15 minutes.
The reliability of the ColiMinder has been demonstrated in many installations where the devices have been providing reliable measurement results in continuous operation since 2015.
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.
Its robustness towards environmental influences, like temperature or humidity, is evident in installations like Stonecutter Island Sewage Treatment Plant in Hong Kong, where it has been monitoring effluent 24/7 since 2017 without any issues. Its housing is IP65 protection class, measurement temperature range is 0°C to 42°C.
Sensitivity of the ColiMinder in drinking water measurement corresponds approximately to <1 CFU/100ml, determined by a heterotrophic plate count (HPC) for 100ml sample.
A scientific study by Favere et.al., (2021), published in Water Research, shows that the ColiMinder is the most sensitive instrument available on the market for measuring the microbial quality of water.
ColiMinder instruments calibrate themselves automatically at regular intervals, therefore no manual re-calibration is necessary.
No. ColiMinder measures enzymatic activity of the respective target organism.
E.g., mMFU / 100 ml (Modified Fishman Units per 100 ml), is the scientifically defined unit for β-D-Glucuronidase activity.
Enzymatic activity values are not directly convertible to CFU because enzymatic activity reflects the metabolic activity of all living organisms, not just cultivable ones. However, mMFU correlates well with the traditional method based CFU tests, and is validated against culture methods in multiple peer-reviewed studies. The correlation is confirmed in your specific application during the initial validation phase.
Every ColiMinder is factory-calibrated to the respective scientific definition of enzymatic activity, providing the results in these scientifically defined parameters (e.g., ín MFU Modified Fishman Units for E. coli specific enzymatic activity).
ColiMinder performs automatic self-calibration during every measurement cycle — no manual intervention required. The instrument uses an internal reference standard to normalise each result, compensating for reagent aging, temperature variation, and optical drift. VWMS offers professional Recalibration & Check services.
Choose based on power supply and deployment scenario:
- CMI-02 (Standard) — permanent installation with AC power (86–264 V), ambient up to 40°C. The most widely deployed model.
- CMI-02-S (Silent) — same as Standard but optimised for quieter, climate-controlled environments (max 28°C).
- CMI-02-E (Low Energy) — runs on 12 V DC: solar panels, batteries, or vehicle power. Ideal for remote sites or off-grid deployments.
- CMI-02-M (Mobile / ERU) — rack-mounted Emergency Response Unit with 10-fold multisampler, battery, and all consumables integrated. Deployable in vehicles or boats for crisis response.
ColiMinder is a professional instrument for industrial and municipal water monitoring. Pricing depends on the model, required add-on modules, reagent volume, and service contract. We do not publish list prices, but please do contact our team or your regional sales partner for a project-specific quotation. We are happy to discuss return-on-investment calculations based on your current sampling costs.
No. ColiMinder works directly with raw water samples — no filtration, dilution, concentration, or chemical preparation is required before the measurement. The instrument compensates for turbidity automatically. This makes installation simpler and eliminates the risk of contamination or loss of organisms during pre-treatment steps.
Less than 1 hour per year for routine on-site maintenance. The main periodic task is refilling the reagents (capacity: up to 1,000 measurements — approximately 18 days at maximum frequency) and consumables (rinsing water, washing solution). Cleaning, re-calibration, and self-diagnostics run automatically. VWMS offers remote support and check, and its service partners around the globe are available for planned service visits and checks.
ColiMinder supports a wide range of connectivity options:
- Wi-Fi, LAN, internal GPRS/LTE modem
- RS232 / RS485 and Modbus TCP for SCADA integration
- 4–20 mA analogue output (optional)
- USB data export directly from the device
- HDMI output for local display
- Alarm relay output or alarm flashlight
- ISCO autosampler control port
ColiMinder (IP65) can be installed in any sheltered location — indoors, in a technical cabinet, or in an enclosure. It should be protected from direct sunlight and rain and, if deployed in a cabinet, air should be able to circulate (no air-condition required, however). Operating temperature range depends on the model (max 28–42°C ambient). ColiMinder has been successfully operated in extreme conditions: during Typhoon Mangkhut (Signal 10) in Hong Kong, in tropical heat in Nigeria, and in desert environments in the UAE. Its robustness against other environmental influences (e.g. chemically enhanced environment) is proven in many rough environment applications.
ColiMinder’s measurement principle and field performance are documented in multiple peer-reviewed publications, including in Water Research (Elsevier) and Hydrogeology Journal (Springer). For example, a 2021 study in Water Research confirmed ColiMinder as the only rapid method achieving 100% detection rate across all tested contamination events. Visit our Downloads section for PDFs and links to publications.
The typical process:
- Consultation — talk to our team about your application, sampling points, and monitoring goals
- Site assessment — check available power supply, access, sample pressure, and ambient conditions with us
- Proposal & quotation — we recommend the right model and add-on modules
- Installation & commissioning — on-site by VWMS or a certified sales partner
- Validation — establish correlation to your existing lab method (validation guidelines provided)
- Ongoing support — remote monitoring, service contract, and reagent supply
Still have a question?
Browse our Use Cases to see ColiMinder in your application area, or get in touch directly.