Analytical methods for microbial water quality

Microbiology laboratory

KWR’s microbiology laboratory carries out analyses of biological water quality. We apply existing analytical methods as well as develop new ones, such as molecular techniques. We conduct annual proficiency tests for laboratories, and are a test laboratory for Household Water Treatment Technologies for the World Health Organization (WHO).

Analysis of microbial water quality

Our experts dispose of various analytical methods to manage microbial water quality. We determine whether (drinking) water complies with legal requirements for microbial safety, and whether the water quality is safeguarded during its transport and distribution. We have various means of measuring the biological stability of water, for example, by using a biofilm monitor, measuring the AOC concentrations or the active biomass content (via ATP), culture methods, and a method to measure the biofilm formation potential of water, in pipe materials for instance. We also check for the presence of protozoa in order to determine parasitological water quality.

Proficiency tests for laboratories

Every year, using the Youden technique, we carry out about 45 proficiency tests for laboratories on more than 100 parameters in different types of water. This allows the laboratories to compare their water research data and to obtain information about the effectiveness of their analytical methods. These proficiency tests are also an important (environmental) measurement tool.

Molecular techniques

In our laboratories we are continually developing new analytical methods, including molecular, or DNA, techniques. This enables us to trace sources of microbial contamination, not only in drinking water but also in bathing water for example. We also apply quantitative PCR methods to determine what types of microorganism – e.g., blue-green algae – are present in the water. Moreover, the Next Generation Sequencing (NGS) method allows us to characterise microbial populations.

WHO test laboratory

Not all countries dispose of centralised treatment and distribution of safe drinking water. In those that don’t, the market offers a variety of small-scale systems with which people can treat their water at the tap, in their homes for instance. As a WHO Collaborating Centre, we function as a test laboratory for such Household Water Treatment Technologies. The knowledge produced can be used to advise governments in countries, where drinking water is of lesser quality, about which systems are suitable for local water treatment and water quality improvement.

Toxicological determinations with bioassays

In addition to analysing the microbiological water quality, the microbiology laboratory also performs bioassays for the determination of chemical water quality, such as the Ames fluctuation test, umu test, comet assay and oxidative stress assay. These tests are applied to investigate whether a water sample contains compounds that may affect biological processes related to human health or damage cells, for example, DNA damage.

Sample collection and preparation is essential for the interpretation of possible adverse effects. Water samples may be concentrated in advance by the Laboratory of Materials and Chemical Analysis.