Monitoring of drinking water quality — even in times of crisis

The provision of drinking water is one of the most critical tasks in emergency situations. It must be ensured that potential raw water sources do not contain harmful pathogens or toxins. While sensory, physical, and chemical parameters can be determined within minutes, microbial contamination can only be detected after at least 18 hours—or, in the case of total bacterial count, only after more than 40 hours of incubation. As a result, water treatment and supply can only begin with significant delays.

The overarching goal of NANObeST was to research, test, and establish a field-ready, mobile rapid analysis system capable of detecting a wide range of microbial contaminants in water samples within two hours. In addition, the total bacterial count of treated and stored clean water should be monitored in a timely manner for quality control using a stationary analysis system. This is made possible through the use of special magnetic nanosensors, which selectively bind and magnetically label specific microbes or their produced signaling molecules in the water being tested.

With the targeted analytical methods, the THW and other organizations responsible for drinking water supply and safety will be able to rapidly detect and quantify microbial contamination in raw water sources during deployment, identify microbial hazards in the provided drinking water, and significantly accelerate routine water quality monitoring compared to established methods.

Fraunhofer IME was primarily responsible for developing customized detection approaches for the scenarios specified by the THW. These include not only the determination of total bacterial counts but also the detection of fecal contamination and hazardous substances. Another key objective at Fraunhofer IME was to increase the analysis speed, particularly in connection with the mobile analysis device, to enable rapid screening of raw water sources for contamination.

The THW and other aid organizations must be prepared for a wide range of deployment scenarios. In the area of drinking water supply, this primarily involves accessing and treating raw water sources, monitoring the quality of treated water, detecting hazards for their own personnel, and preventing the spread of disease. For the development of the analysis devices, typical deployment scenarios for the THW and other aid organizations were used as a basis:

1)      Microbial contamination:

a) Rapid detection and quantification of microbial contamination in raw water sources: In the early stages of deployments, it is crucial to check potential raw water sources, particularly for fecal contamination. This reduces the risk to personnel and prevents setting up complex water treatment systems at unsuitable locations. The same applies to the rehabilitation (reactivation) of wells, especially during overseas missions.

b) Quality monitoring of provided drinking water: In disaster situations, when drinking water — e.g., from water bladders or tankers — must be distributed to the population or treated on-site, the water must undergo continuous monitoring. The total bacterial count provides information on microbial contamination of the sample and indicates potential hygiene deficiencies or microbial growth in water storage. A waiting period of one and a half to two days due to currently available analysis methods is unacceptable in such situations.

2)      Hazard detection for personnel:

In large-scale deployments, vacant buildings are often used to house emergency personnel. Since the existing drinking water installations may have been out of operation for a long time, the likelihood of Legionella contamination is high. Rapid analysis is essential to protect the people accommodated there. Conventional methods require at least 7 days for this.

3)      Toxin analysis and disease prevention:

Particularly in overseas deployments, there is an increased risk of pathogens such as the cholera bacterium and other epidemic agents. These produce specific bacterial toxins, such as cholera toxin. On-site hygiene conditions are often poor, and the early detection of these toxins allows for the prevention or containment of infectious disease outbreaks, such as cholera, before they can spread.