Behaviour and identification of micropollutants and microorganisms

Findings on the behaviour of “new” or previously unknown micropollutants in aquatic systems and particularly in drinking water treatment are not generally available. However, they can be obtained via specific, practical laboratory trials with subsequent analysis. In particular, these tackle issues on how to remove substances using specific water treatment methods. As micropollutants can be transformed in natural degradation processes and in technical water treatment, clarifying their transformation products is a key component when assessing a treatment process. Similarly, we have cutting-edge methods to clarify microbiological contamination sources and to assess evidence of “new” microorganisms. We offer our customers solutions and concepts using analytical process engineering laboratory testing under practical conditions for support and the targeted testing of the latest issues relating to micropollutants, microorganisms and possible pathogens.

Simulation of aerobic bank filtration

To simulate biological decomposition processes during aerobic bank filtration, we dose surface water with an organic micropollutant at concentrations that reflect those in the environment. A test runs for 30 days, during which the water is continuously aerated and protected from daylight and is pumped into circulation over a porous material (sintered glass beads). This porous material is not adsorptive and provides the ideal conditions for microorganisms to develop a biofilm similar to that in an infiltration zone. Interpreting the obtained degradation curves together with the existing broad database of previously investigated micropollutants gives a good estimation of biological degradability.

Oxidative degradation during ozonation

Laboratory-scale ozonation trials offer a good simulation of the oxidising micropollutants in large-scale treatment. As required, treatments can be applied in a batch trial or using methods with direct ozone input. The generated transformation products can also be characterised using various downstream analytical methods, for example high-resolution mass spectrometry processes.

Ozonation coupled with bioactive or biosorptive treatment steps

Studies on transformation products following ozonation without the inclusion of a subsequent bioactive step do not give the full picture. For this reason we have continuous ozonation available to carry out combined lab-scale trials, which can be coupled, for instance, with bioactive slow sand or activated carbon filtration. This makes it possible to simulate oxidisation and biological decomposition together.

Adsorptive removal using activated carbon

In order to characterise substance behaviour in adsoptive processes filtration tests with granulated activated carbon can be performed in addition to adsorption isotherms. This also takes the kinetic effects of adsorption into account. A few days under standardised conditions gives practical information on how efficient it is to remove micropollutants using activated carbon.

Assessment of microbiological findings (E. coli, coliform bacteria, enterococci) in drinking water and assessment of microbiological findings (Pseudomonas aeruginosa, Legionella) in drinking water installations

The majority of microbiological problems in drinking water installations are related to Legionella or Pseudomonas aeruginosa. We advise our customers on practical problems, e.g. in hospitals, and help to assess and classify findings and to derive countermeasures.

Detection and evaluation of pathogens (e.g. Campylobacter, Pseudomonas aeruginosa, Legionella)

Usually, drinking water is analysed for indicator bacteria. In various cases, it may also be useful to investigate pathogens – or the authorities may require this (e.g. testing for Pseudomonas aeruginosa following building work). We offer cultural and molecular biological testing for various pathogens and consultation when evaluating the evidence.

Identification and assessment of faecal contamination sources (microbial source tracking)

The implementation of efficient and cost-effective measures to improve the microbiological water quality in a catchment area requires the determination of the origin of the faecal contamination to be as precise as possible. However, the microbiological methods currently used for quality control provide no information on the origin of the contamination. We offer new molecular biological methods that make it possible to identify faecal contamination sources.

Detection and evaluation of antibiotic-resistant bacteria and antibiotic resistance genes

The long-term and extensive use of antibiotics has not only encouraged the development and dispersion of antibiotic-resistant bacteria and antibiotic resistance genes in the clinical field but also in the aquatic environment. For this reason, antibiotic-resistant bacteria and antibiotic resistance genes are the subject of increasing discussion as new parameters in the evaluation of hygienic water quality. A series of research projects has given us a wealth of experience on the detection of antibiotic resistance in the environment. We can also offer relevant testing and an assessment of the results for contract work.

Detection and evaluation of viruses

Human pathogenic viruses can be harmful to a person’s health even at very low concentrations because of their low infective dose. For this reason, WHO recommends the presence of human pathogenic viruses are also taken into account in raw water risk assessments. The rapid detection of these low but hygienically relevant virus concentrations presents a huge challenge to detection techniques. TZW’s on-going and completed research projects have provided extensive experience in the detection of viruses in the environment. Similarly, TZW advocates a continuous further development and validation of molecular biological methods to quickly detect viruses – also for use, for example, in disinfection processes.